IT. Expert System.

All Implemented Interfaces:

Drawable.Callback, AccessibilityEventSource, KeyEvent.Callback, ViewManager, ViewParent

public class ViewPager
extends ViewGroup

• Nested Class Summary

  Nested Classes

  Modifier and Type	Class and Description
  static class	ViewPager.LayoutParams Layout parameters that should be supplied for views added to a ViewPager.
  static interface	ViewPager.OnPageChangeListener Callback interface for responding to changing state of the selected page.
  static interface	ViewPager.PageTransformer A PageTransformer is invoked whenever a visible/attached page is scrolled.
  static class	ViewPager.SavedState This is the persistent state that is saved by ViewPager.
  static class	ViewPager.SimpleOnPageChangeListener Simple implementation of the ViewPager.OnPageChangeListener interface with stub implementations of each method.

  • Nested classes/interfaces inherited from class android.view.ViewGroup

    ViewGroup.MarginLayoutParams, ViewGroup.OnHierarchyChangeListener

  • Nested classes/interfaces inherited from class android.view.View

    View.AccessibilityDelegate, View.BaseSavedState, View.DragShadowBuilder, View.MeasureSpec, View.OnAttachStateChangeListener, View.OnClickListener, View.OnCreateContextMenuListener, View.OnDragListener, View.OnFocusChangeListener, View.OnGenericMotionListener, View.OnHoverListener, View.OnKeyListener, View.OnLayoutChangeListener, View.OnLongClickListener, View.OnSystemUiVisibilityChangeListener, View.OnTouchListener

• Field Summary

  Fields

  Modifier and Type	Field and Description
  static int	SCROLL_STATE_DRAGGING Indicates that the pager is currently being dragged by the user.
  static int	SCROLL_STATE_IDLE Indicates that the pager is in an idle, settled state.
  static int	SCROLL_STATE_SETTLING Indicates that the pager is in the process of settling to a final position.

  • Fields inherited from class android.view.ViewGroup

    CLIP_BOUNDS, CLIP_TO_PADDING_MASK, FLAG_DISALLOW_INTERCEPT, FLAG_SUPPORT_STATIC_TRANSFORMATIONS, FLAG_USE_CHILD_DRAWING_ORDER, FOCUS_AFTER_DESCENDANTS, FOCUS_BEFORE_DESCENDANTS, FOCUS_BLOCK_DESCENDANTS, mDisappearingChildren, mGroupFlags, mOnHierarchyChangeListener, mPersistentDrawingCache, OPTICAL_BOUNDS, PERSISTENT_ALL_CACHES, PERSISTENT_ANIMATION_CACHE, PERSISTENT_NO_CACHE, PERSISTENT_SCROLLING_CACHE

  • Fields inherited from class android.view.View

    ALPHA, DEBUG_LAYOUT_PROPERTY, DRAG_FLAG_GLOBAL, DRAWING_CACHE_QUALITY_AUTO, DRAWING_CACHE_QUALITY_HIGH, DRAWING_CACHE_QUALITY_LOW, EMPTY_STATE_SET, ENABLED_FOCUSED_SELECTED_STATE_SET, ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET, ENABLED_FOCUSED_STATE_SET, ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET, ENABLED_SELECTED_STATE_SET, ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET, ENABLED_STATE_SET, ENABLED_WINDOW_FOCUSED_STATE_SET, FIND_VIEWS_WITH_ACCESSIBILITY_NODE_PROVIDERS, FIND_VIEWS_WITH_CONTENT_DESCRIPTION, FIND_VIEWS_WITH_TEXT, FOCUS_BACKWARD, FOCUS_DOWN, FOCUS_FORWARD, FOCUS_LEFT, FOCUS_RIGHT, FOCUS_UP, FOCUSABLES_ALL, FOCUSABLES_TOUCH_MODE, FOCUSED_SELECTED_STATE_SET, FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET, FOCUSED_STATE_SET, FOCUSED_WINDOW_FOCUSED_STATE_SET, GONE, HAPTIC_FEEDBACK_ENABLED, IMPORTANT_FOR_ACCESSIBILITY_AUTO, IMPORTANT_FOR_ACCESSIBILITY_NO, IMPORTANT_FOR_ACCESSIBILITY_YES, INVISIBLE, KEEP_SCREEN_ON, LAYER_TYPE_HARDWARE, LAYER_TYPE_NONE, LAYER_TYPE_SOFTWARE, LAYOUT_DIRECTION_INHERIT, LAYOUT_DIRECTION_LOCALE, LAYOUT_DIRECTION_LTR, LAYOUT_DIRECTION_RTL, mBottom, mCachingFailed, mContext, mCurrentAnimation, MEASURED_HEIGHT_STATE_SHIFT, MEASURED_SIZE_MASK, MEASURED_STATE_MASK, MEASURED_STATE_TOO_SMALL, mInputEventConsistencyVerifier, mLayoutParams, mLeft, mPaddingBottom, mPaddingLeft, mPaddingRight, mPaddingTop, mParent, mRight, mScrollX, mScrollY, mTag, mTop, mUserPaddingBottom, mUserPaddingLeft, mUserPaddingRight, NO_ID, OVER_SCROLL_ALWAYS, OVER_SCROLL_IF_CONTENT_SCROLLS, OVER_SCROLL_NEVER, PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET, PRESSED_ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET, PRESSED_ENABLED_FOCUSED_STATE_SET, PRESSED_ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET, PRESSED_ENABLED_SELECTED_STATE_SET, PRESSED_ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET, PRESSED_ENABLED_STATE_SET, PRESSED_ENABLED_WINDOW_FOCUSED_STATE_SET, PRESSED_FOCUSED_SELECTED_STATE_SET, PRESSED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET, PRESSED_FOCUSED_STATE_SET, PRESSED_FOCUSED_WINDOW_FOCUSED_STATE_SET, PRESSED_SELECTED_STATE_SET, PRESSED_SELECTED_WINDOW_FOCUSED_STATE_SET, PRESSED_STATE_SET, PRESSED_WINDOW_FOCUSED_STATE_SET, PUBLIC_STATUS_BAR_VISIBILITY_MASK, ROTATION, ROTATION_X, ROTATION_Y, SCALE_X, SCALE_Y, SCREEN_STATE_OFF, SCREEN_STATE_ON, SCROLLBAR_POSITION_DEFAULT, SCROLLBAR_POSITION_LEFT, SCROLLBAR_POSITION_RIGHT, SCROLLBARS_INSIDE_INSET, SCROLLBARS_INSIDE_OVERLAY, SCROLLBARS_OUTSIDE_INSET, SCROLLBARS_OUTSIDE_OVERLAY, SELECTED_STATE_SET, SELECTED_WINDOW_FOCUSED_STATE_SET, SOUND_EFFECTS_ENABLED, STATUS_BAR_DISABLE_BACK, STATUS_BAR_DISABLE_CLOCK, STATUS_BAR_DISABLE_EXPAND, STATUS_BAR_DISABLE_HOME, STATUS_BAR_DISABLE_NOTIFICATION_ALERTS, STATUS_BAR_DISABLE_NOTIFICATION_ICONS, STATUS_BAR_DISABLE_NOTIFICATION_TICKER, STATUS_BAR_DISABLE_RECENT, STATUS_BAR_DISABLE_SEARCH, STATUS_BAR_DISABLE_SYSTEM_INFO, STATUS_BAR_HIDDEN, STATUS_BAR_VISIBLE, SYSTEM_UI_CLEARABLE_FLAGS, SYSTEM_UI_FLAG_FULLSCREEN, SYSTEM_UI_FLAG_HIDE_NAVIGATION, SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN, SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION, SYSTEM_UI_FLAG_LAYOUT_STABLE, SYSTEM_UI_FLAG_LOW_PROFILE, SYSTEM_UI_FLAG_VISIBLE, SYSTEM_UI_LAYOUT_FLAGS, TEXT_ALIGNMENT_CENTER, TEXT_ALIGNMENT_GRAVITY, TEXT_ALIGNMENT_INHERIT, TEXT_ALIGNMENT_TEXT_END, TEXT_ALIGNMENT_TEXT_START, TEXT_ALIGNMENT_VIEW_END, TEXT_ALIGNMENT_VIEW_START, TEXT_DIRECTION_ANY_RTL, TEXT_DIRECTION_FIRST_STRONG, TEXT_DIRECTION_INHERIT, TEXT_DIRECTION_LOCALE, TEXT_DIRECTION_LTR, TEXT_DIRECTION_RTL, TRANSLATION_X, TRANSLATION_Y, VIEW_LOG_TAG, VISIBLE, WINDOW_FOCUSED_STATE_SET, X, Y

• Constructor Summary

  Constructors

  Constructor and Description
  ViewPager(Context context)
  ViewPager(Context context, AttributeSet attrs)

• Method Summary

  Methods

  Modifier and Type	Method and Description
  void	addFocusables(ArrayList<View> views, int direction, int focusableMode) We only want the current page that is being shown to be focusable.
  void	addTouchables(ArrayList<View> views) We only want the current page that is being shown to be touchable.
  void	addView(View child, int index, ViewGroup.LayoutParams params) Adds a child view with the specified layout parameters.
  boolean	arrowScroll(int direction)
  boolean	beginFakeDrag() Start a fake drag of the pager.
  protected boolean	canScroll(View v, boolean checkV, int dx, int x, int y) Tests scrollability within child views of v given a delta of dx.
  protected boolean	checkLayoutParams(ViewGroup.LayoutParams p)
  void	computeScroll() Called by a parent to request that a child update its values for mScrollX and mScrollY if necessary.
  boolean	dispatchKeyEvent(KeyEvent event) Dispatch a key event to the next view on the focus path.
  boolean	dispatchPopulateAccessibilityEvent(AccessibilityEvent event) Dispatches an AccessibilityEvent to the View first and then to its children for adding their text content to the event.
  void	draw(Canvas canvas) Manually render this view (and all of its children) to the given Canvas.
  protected void	drawableStateChanged() This function is called whenever the state of the view changes in such a way that it impacts the state of drawables being shown.
  void	endFakeDrag() End a fake drag of the pager.
  boolean	executeKeyEvent(KeyEvent event) You can call this function yourself to have the scroll view perform scrolling from a key event, just as if the event had been dispatched to it by the view hierarchy.
  void	fakeDragBy(float xOffset) Fake drag by an offset in pixels.
  protected ViewGroup.LayoutParams	generateDefaultLayoutParams() Returns a set of default layout parameters.
  ViewGroup.LayoutParams	generateLayoutParams(AttributeSet attrs) Returns a new set of layout parameters based on the supplied attributes set.
  protected ViewGroup.LayoutParams	generateLayoutParams(ViewGroup.LayoutParams p) Returns a safe set of layout parameters based on the supplied layout params.
  PagerAdapter	getAdapter() Retrieve the current adapter supplying pages.
  protected int	getChildDrawingOrder(int childCount, int i) Returns the index of the child to draw for this iteration.
  int	getCurrentItem()
  int	getOffscreenPageLimit() Returns the number of pages that will be retained to either side of the current page in the view hierarchy in an idle state.
  int	getPageMargin() Return the margin between pages.
  boolean	isFakeDragging() Returns true if a fake drag is in progress.
  protected void	onAttachedToWindow() This is called when the view is attached to a window.
  protected void	onDetachedFromWindow() This is called when the view is detached from a window.
  protected void	onDraw(Canvas canvas) Implement this to do your drawing.
  boolean	onInterceptTouchEvent(MotionEvent ev) Implement this method to intercept all touch screen motion events.
  protected void	onLayout(boolean changed, int l, int t, int r, int b) Called from layout when this view should assign a size and position to each of its children.
  protected void	onMeasure(int widthMeasureSpec, int heightMeasureSpec) Measure the view and its content to determine the measured width and the measured height.
  protected void	onPageScrolled(int position, float offset, int offsetPixels) This method will be invoked when the current page is scrolled, either as part of a programmatically initiated smooth scroll or a user initiated touch scroll.
  protected boolean	onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) We only want the current page that is being shown to be focusable.
  void	onRestoreInstanceState(Parcelable state) Hook allowing a view to re-apply a representation of its internal state that had previously been generated by View.onSaveInstanceState().
  Parcelable	onSaveInstanceState() Hook allowing a view to generate a representation of its internal state that can later be used to create a new instance with that same state.
  protected void	onSizeChanged(int w, int h, int oldw, int oldh) This is called during layout when the size of this view has changed.
  boolean	onTouchEvent(MotionEvent ev) Implement this method to handle touch screen motion events.
  void	setAdapter(PagerAdapter adapter) Set a PagerAdapter that will supply views for this pager as needed.
  void	setCurrentItem(int item) Set the currently selected page.
  void	setCurrentItem(int item, boolean smoothScroll) Set the currently selected page.
  void	setOffscreenPageLimit(int limit) Set the number of pages that should be retained to either side of the current page in the view hierarchy in an idle state.
  void	setOnPageChangeListener(ViewPager.OnPageChangeListener listener) Set a listener that will be invoked whenever the page changes or is incrementally scrolled.
  void	setPageMargin(int marginPixels) Set the margin between pages.
  void	setPageMarginDrawable(Drawable d) Set a drawable that will be used to fill the margin between pages.
  void	setPageMarginDrawable(int resId) Set a drawable that will be used to fill the margin between pages.
  void	setPageTransformer(boolean reverseDrawingOrder, ViewPager.PageTransformer transformer) Set a ViewPager.PageTransformer that will be called for each attached page whenever the scroll position is changed.
  protected boolean	verifyDrawable(Drawable who) If your view subclass is displaying its own Drawable objects, it should override this function and return true for any Drawable it is displaying.

  • Methods inherited from class android.view.ViewGroup

    addChildrenForAccessibility, addStatesFromChildren, addView, addView, addView, addView, addViewInLayout, addViewInLayout, attachLayoutAnimationParameters, attachViewToParent, bringChildToFront, canAnimate, childAccessibilityStateChanged, childDrawableStateChanged, childHasTransientStateChanged, cleanupLayoutState, clearChildFocus, clearDisappearingChildren, clearFocus, debug, detachAllViewsFromParent, detachViewFromParent, detachViewFromParent, detachViewsFromParent, dispatchConfigurationChanged, dispatchDisplayHint, dispatchDragEvent, dispatchDraw, dispatchFinishTemporaryDetach, dispatchFreezeSelfOnly, dispatchGenericFocusedEvent, dispatchGenericPointerEvent, dispatchGetDisplayList, dispatchHoverEvent, dispatchKeyEventPreIme, dispatchKeyShortcutEvent, dispatchRestoreInstanceState, dispatchSaveInstanceState, dispatchSetActivated, dispatchSetPressed, dispatchSetSelected, dispatchStartTemporaryDetach, dispatchSystemUiVisibilityChanged, dispatchThawSelfOnly, dispatchTouchEvent, dispatchTrackballEvent, dispatchUnhandledMove, dispatchVisibilityChanged, dispatchWindowFocusChanged, dispatchWindowSystemUiVisiblityChanged, dispatchWindowVisibilityChanged, drawChild, endViewTransition, findFocus, findViewByPredicateTraversal, findViewsWithText, findViewTraversal, findViewWithTagTraversal, fitSystemWindows, focusableViewAvailable, focusSearch, gatherTransparentRegion, getChildAt, getChildCount, getChildMeasureSpec, getChildStaticTransformation, getChildVisibleRect, getDescendantFocusability, getFocusedChild, getLayoutAnimation, getLayoutAnimationListener, getLayoutMode, getLayoutTransition, getPersistentDrawingCache, hasFocus, hasFocusable, hasHoveredChild, hasTransientState, indexOfChild, internalSetPadding, invalidateChild, invalidateChildFast, invalidateChildInParent, isAlwaysDrawnWithCacheEnabled, isAnimationCacheEnabled, isChildrenDrawingOrderEnabled, isChildrenDrawnWithCacheEnabled, isMotionEventSplittingEnabled, isTransformedTouchPointInView, jumpDrawablesToCurrentState, layout, makeOptionalFitsSystemWindows, measureChild, measureChildren, measureChildWithMargins, offsetChildrenTopAndBottom, offsetDescendantRectToMyCoords, offsetRectIntoDescendantCoords, onAnimationEnd, onAnimationStart, onChildVisibilityChanged, onCreateDrawableState, onDebugDraw, onDebugDrawMargins, onInterceptHoverEvent, onRequestSendAccessibilityEvent, onSetLayoutParams, onViewAdded, onViewRemoved, recomputeViewAttributes, removeAllViews, removeAllViewsInLayout, removeDetachedView, removeView, removeViewAt, removeViewInLayout, removeViews, removeViewsInLayout, requestChildFocus, requestChildRectangleOnScreen, requestDisallowInterceptTouchEvent, requestFocus, requestSendAccessibilityEvent, requestTransitionStart, requestTransparentRegion, resetAccessibilityStateChanged, resetResolvedDrawables, resetResolvedLayoutDirection, resetResolvedPadding, resetResolvedTextAlignment, resetResolvedTextDirection, resetRtlProperties, resolveDrawables, resolveLayoutDirection, resolveLayoutParams, resolvePadding, resolveRtlPropertiesIfNeeded, resolveTextAlignment, resolveTextDirection, scheduleLayoutAnimation, setAddStatesFromChildren, setAlwaysDrawnWithCacheEnabled, setAnimationCacheEnabled, setChildrenDrawingCacheEnabled, setChildrenDrawingOrderEnabled, setChildrenDrawnWithCacheEnabled, setClipChildren, setClipToPadding, setDescendantFocusability, setLayoutAnimation, setLayoutAnimationListener, setLayoutMode, setLayoutTransition, setMotionEventSplittingEnabled, setOnHierarchyChangeListener, setPersistentDrawingCache, setStaticTransformationsEnabled, shouldDelayChildPressedState, showContextMenuForChild, startActionModeForChild, startLayoutAnimation, startViewTransition, updateViewLayout

  • Methods inherited from class android.view.View

    addFocusables, addOnAttachStateChangeListener, addOnLayoutChangeListener, animate, announceForAccessibility, applyDrawableToTransparentRegion, awakenScrollBars, awakenScrollBars, awakenScrollBars, bringToFront, buildDrawingCache, buildDrawingCache, buildLayer, callOnClick, cancelLongPress, canHaveDisplayList, canResolveLayoutDirection, canScrollHorizontally, canScrollVertically, checkInputConnectionProxy, clearAccessibilityFocus, clearAnimation, combineMeasuredStates, computeHorizontalScrollExtent, computeHorizontalScrollOffset, computeHorizontalScrollRange, computeOpaqueFlags, computeVerticalScrollExtent, computeVerticalScrollOffset, computeVerticalScrollRange, createAccessibilityNodeInfo, createContextMenu, debug, debugIndent, destroyDrawingCache, destroyHardwareResources, dispatchGenericMotionEvent, dispatchPointerEvent, findViewById, findViewByPredicate, findViewByPredicateInsideOut, findViewWithTag, fitsSystemWindows, focusSearch, forceLayout, generateViewId, getAccessibilityCursorPosition, getAccessibilityDelegate, getAccessibilityNodeProvider, getAccessibilityViewId, getAccessibilityWindowId, getAlpha, getAnimation, getApplicationWindowToken, getBackground, getBaseline, getBottom, getBottomFadingEdgeStrength, getBottomPaddingOffset, getCameraDistance, getContentDescription, getContext, getContextMenuInfo, getDefaultSize, getDisplay, getDisplayList, getDrawableState, getDrawingCache, getDrawingCache, getDrawingCacheBackgroundColor, getDrawingCacheQuality, getDrawingRect, getDrawingTime, getFadeHeight, getFadeTop, getFilterTouchesWhenObscured, getFitsSystemWindows, getFocusables, getFocusedRect, getGlobalVisibleRect, getGlobalVisibleRect, getHandler, getHardwareRenderer, getHeight, getHitRect, getHorizontalFadingEdgeLength, getHorizontalScrollbarHeight, getHorizontalScrollFactor, getId, getImportantForAccessibility, getIterableTextForAccessibility, getIteratorForGranularity, getKeepScreenOn, getKeyDispatcherState, getLabelFor, getLayerType, getLayoutDirection, getLayoutParams, getLeft, getLeftFadingEdgeStrength, getLeftPaddingOffset, getLocalVisibleRect, getLocationInWindow, getLocationOnScreen, getMatrix, getMeasuredHeight, getMeasuredHeightAndState, getMeasuredState, getMeasuredWidth, getMeasuredWidthAndState, getMinimumHeight, getMinimumWidth, getNextFocusDownId, getNextFocusForwardId, getNextFocusLeftId, getNextFocusRightId, getNextFocusUpId, getOnFocusChangeListener, getOpticalInsets, getOverScrollMode, getPaddingBottom, getPaddingEnd, getPaddingLeft, getPaddingRight, getPaddingStart, getPaddingTop, getParent, getParentForAccessibility, getPivotX, getPivotY, getRawLayoutDirection, getRawTextAlignment, getRawTextDirection, getResources, getRight, getRightFadingEdgeStrength, getRightPaddingOffset, getRootView, getRotation, getRotationX, getRotationY, getScaleX, getScaleY, getScrollBarDefaultDelayBeforeFade, getScrollBarFadeDuration, getScrollBarSize, getScrollBarStyle, getScrollX, getScrollY, getSolidColor, getSuggestedMinimumHeight, getSuggestedMinimumWidth, getSystemUiVisibility, getTag, getTag, getTextAlignment, getTextDirection, getTop, getTopFadingEdgeStrength, getTopPaddingOffset, getTouchables, getTouchDelegate, getTranslationX, getTranslationY, getVerticalFadingEdgeLength, getVerticalScrollbarPosition, getVerticalScrollbarWidth, getVerticalScrollFactor, getViewRootImpl, getViewTreeObserver, getVisibility, getWidth, getWindowAttachCount, getWindowSystemUiVisibility, getWindowToken, getWindowVisibility, getWindowVisibleDisplayFrame, getX, getY, hackTurnOffWindowResizeAnim, hasOnClickListeners, hasOpaqueScrollbars, hasOverlappingRendering, hasWindowFocus, includeForAccessibility, inflate, initializeFadingEdge, initializeScrollbars, invalidate, invalidate, invalidate, invalidateDrawable, invalidateParentCaches, invalidateParentIfNeeded, isActionableForAccessibility, isActivated, isClickable, isDirty, isDrawingCacheEnabled, isDuplicateParentStateEnabled, isEnabled, isFocusable, isFocusableInTouchMode, isFocused, isHapticFeedbackEnabled, isHardwareAccelerated, isHorizontalFadingEdgeEnabled, isHorizontalScrollBarEnabled, isHovered, isImportantForAccessibility, isInEditMode, isInScrollingContainer, isInTouchMode, isLayoutDirectionInherited, isLayoutRequested, isLayoutRtl, isLongClickable, isOpaque, isPaddingOffsetRequired, isPaddingRelative, isPressed, isRootNamespace, isSaveEnabled, isSaveFromParentEnabled, isScrollbarFadingEnabled, isScrollContainer, isSelected, isShown, isSoundEffectsEnabled, isTextAlignmentInherited, isTextDirectionInherited, isVerticalFadingEdgeEnabled, isVerticalScrollBarEnabled, isVerticalScrollBarHidden, isVisibleToUser, isVisibleToUser, measure, mergeDrawableStates, notifyAccessibilityStateChanged, offsetLeftAndRight, offsetTopAndBottom, onCheckIsTextEditor, onCloseSystemDialogs, onConfigurationChanged, onCreateContextMenu, onCreateInputConnection, onDisplayHint, onDragEvent, onDrawHorizontalScrollBar, onDrawScrollBars, onDrawVerticalScrollBar, onFilterTouchEventForSecurity, onFinishInflate, onFinishTemporaryDetach, onFocusChanged, onFocusLost, onGenericMotionEvent, onHoverChanged, onHoverEvent, onInitializeAccessibilityEvent, onInitializeAccessibilityNodeInfo, onKeyDown, onKeyLongPress, onKeyMultiple, onKeyPreIme, onKeyShortcut, onKeyUp, onOverScrolled, onPopulateAccessibilityEvent, onResolveDrawables, onRtlPropertiesChanged, onScreenStateChanged, onScrollChanged, onSetAlpha, onStartTemporaryDetach, onTrackballEvent, onVisibilityChanged, onWindowFocusChanged, onWindowSystemUiVisibilityChanged, onWindowVisibilityChanged, outputDirtyFlags, overScrollBy, performAccessibilityAction, performButtonActionOnTouchDown, performClick, performHapticFeedback, performHapticFeedback, performLongClick, playSoundEffect, post, postDelayed, postInvalidate, postInvalidate, postInvalidateDelayed, postInvalidateDelayed, postInvalidateOnAnimation, postInvalidateOnAnimation, postOnAnimation, postOnAnimationDelayed, recomputePadding, refreshDrawableState, removeCallbacks, removeOnAttachStateChangeListener, removeOnLayoutChangeListener, requestAccessibilityFocus, requestFitSystemWindows, requestFocus, requestFocus, requestFocusFromTouch, requestLayout, requestRectangleOnScreen, requestRectangleOnScreen, resetPaddingToInitialValues, resolveSize, resolveSizeAndState, restoreHierarchyState, saveHierarchyState, scheduleDrawable, scrollBy, scrollTo, sendAccessibilityEvent, sendAccessibilityEventUnchecked, setAccessibilityCursorPosition, setAccessibilityDelegate, setActivated, setAlpha, setAnimation, setBackground, setBackgroundColor, setBackgroundDrawable, setBackgroundResource, setBottom, setCameraDistance, setClickable, setContentDescription, setDisabledSystemUiVisibility, setDrawingCacheBackgroundColor, setDrawingCacheEnabled, setDrawingCacheQuality, setDuplicateParentStateEnabled, setEnabled, setFadingEdgeLength, setFilterTouchesWhenObscured, setFitsSystemWindows, setFocusable, setFocusableInTouchMode, setFrame, setHapticFeedbackEnabled, setHasTransientState, setHorizontalFadingEdgeEnabled, setHorizontalScrollBarEnabled, setHovered, setId, setImportantForAccessibility, setIsRootNamespace, setKeepScreenOn, setLabelFor, setLayerPaint, setLayerType, setLayoutDirection, setLayoutInsets, setLayoutParams, setLeft, setLongClickable, setMeasuredDimension, setMinimumHeight, setMinimumWidth, setNextFocusDownId, setNextFocusForwardId, setNextFocusLeftId, setNextFocusRightId, setNextFocusUpId, setOnClickListener, setOnCreateContextMenuListener, setOnDragListener, setOnFocusChangeListener, setOnGenericMotionListener, setOnHoverListener, setOnKeyListener, setOnLongClickListener, setOnSystemUiVisibilityChangeListener, setOnTouchListener, setOverScrollMode, setPadding, setPaddingRelative, setPivotX, setPivotY, setPressed, setRight, setRotation, setRotationX, setRotationY, setSaveEnabled, setSaveFromParentEnabled, setScaleX, setScaleY, setScrollBarDefaultDelayBeforeFade, setScrollBarFadeDuration, setScrollbarFadingEnabled, setScrollBarSize, setScrollBarStyle, setScrollContainer, setScrollX, setScrollY, setSelected, setSoundEffectsEnabled, setSystemUiVisibility, setTag, setTag, setTagInternal, setTextAlignment, setTextDirection, setTop, setTouchDelegate, setTranslationX, setTranslationY, setVerticalFadingEdgeEnabled, setVerticalScrollBarEnabled, setVerticalScrollbarPosition, setVisibility, setWillNotCacheDrawing, setWillNotDraw, setX, setY, showContextMenu, showContextMenu, startActionMode, startAnimation, startDrag, toString, unscheduleDrawable, unscheduleDrawable, willNotCacheDrawing, willNotDraw

  • Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Methods inherited from interface android.view.ViewParent

    createContextMenu, getParent, getParentForAccessibility, isLayoutRequested, requestFitSystemWindows, requestLayout

• Field Detail

  • SCROLL_STATE_IDLE

    public static final int SCROLL_STATE_IDLE

    Indicates that the pager is in an idle, settled state. The current page is fully in view and no animation is in progress.

    See Also:

    Constant Field Values

  • SCROLL_STATE_DRAGGING

    public static final int SCROLL_STATE_DRAGGING

    Indicates that the pager is currently being dragged by the user.

    See Also:

    Constant Field Values

  • SCROLL_STATE_SETTLING

    public static final int SCROLL_STATE_SETTLING

    Indicates that the pager is in the process of settling to a final position.

    See Also:

    Constant Field Values

• Constructor Detail

  • ViewPager

    public ViewPager(Context context)

  • ViewPager

    public ViewPager(Context context,
             AttributeSet attrs)

• Method Detail

  • onDetachedFromWindow

    protected void onDetachedFromWindow()

    Description copied from class: View
    This is called when the view is detached from a window. At this point it no longer has a surface for drawing.

    Overrides:

    onDetachedFromWindow in class View

    See Also:

    View.onAttachedToWindow()

  • setAdapter

    public void setAdapter(PagerAdapter adapter)

    Set a PagerAdapter that will supply views for this pager as needed.

    Parameters:

    adapter - Adapter to use

  • getAdapter

    public PagerAdapter getAdapter()

    Retrieve the current adapter supplying pages.

    Returns:

    The currently registered PagerAdapter

  • setCurrentItem

    public void setCurrentItem(int item)

    Set the currently selected page. If the ViewPager has already been through its first layout with its current adapter there will be a smooth animated transition between the current item and the specified item.

    Parameters:

    item - Item index to select

  • setCurrentItem

    public void setCurrentItem(int item,
                      boolean smoothScroll)

    Set the currently selected page.

    Parameters:

    item - Item index to select

    smoothScroll - True to smoothly scroll to the new item, false to transition immediately

  • getCurrentItem

    public int getCurrentItem()

  • setOnPageChangeListener

    public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener)

    Set a listener that will be invoked whenever the page changes or is incrementally scrolled. See ViewPager.OnPageChangeListener.

    Parameters:

    listener - Listener to set

  • setPageTransformer

    public void setPageTransformer(boolean reverseDrawingOrder,
                          ViewPager.PageTransformer transformer)

    Set a ViewPager.PageTransformer that will be called for each attached page whenever the scroll position is changed. This allows the application to apply custom property transformations to each page, overriding the default sliding look and feel.

    Note: Prior to Android 3.0 the property animation APIs did not exist. As a result, setting a PageTransformer prior to Android 3.0 (API 11) will have no effect.

    Parameters:

    reverseDrawingOrder - true if the supplied PageTransformer requires page views to be drawn from last to first instead of first to last.

    transformer - PageTransformer that will modify each page's animation properties

  • getChildDrawingOrder

    protected int getChildDrawingOrder(int childCount,
                           int i)

    Description copied from class: ViewGroup
    Returns the index of the child to draw for this iteration. Override this if you want to change the drawing order of children. By default, it returns i.

    NOTE: In order for this method to be called, you must enable child ordering first by calling ViewGroup.setChildrenDrawingOrderEnabled(boolean).

    Overrides:

    getChildDrawingOrder in class ViewGroup

    i - The current iteration.

    Returns:

    The index of the child to draw this iteration.

    See Also:

    ViewGroup.setChildrenDrawingOrderEnabled(boolean), ViewGroup.isChildrenDrawingOrderEnabled()

  • getOffscreenPageLimit

    public int getOffscreenPageLimit()

    Returns the number of pages that will be retained to either side of the current page in the view hierarchy in an idle state. Defaults to 1.

    Returns:

    How many pages will be kept offscreen on either side

    See Also:

    setOffscreenPageLimit(int)

  • setOffscreenPageLimit

    public void setOffscreenPageLimit(int limit)

    Set the number of pages that should be retained to either side of the current page in the view hierarchy in an idle state. Pages beyond this limit will be recreated from the adapter when needed.

    This is offered as an optimization. If you know in advance the number of pages you will need to support or have lazy-loading mechanisms in place on your pages, tweaking this setting can have benefits in perceived smoothness of paging animations and interaction. If you have a small number of pages (3-4) that you can keep active all at once, less time will be spent in layout for newly created view subtrees as the user pages back and forth.

    You should keep this limit low, especially if your pages have complex layouts. This setting defaults to 1.

    Parameters:

    limit - How many pages will be kept offscreen in an idle state.

  • setPageMargin

    public void setPageMargin(int marginPixels)

    Set the margin between pages.

    Parameters:

    marginPixels - Distance between adjacent pages in pixels

    See Also:

    getPageMargin(), setPageMarginDrawable(Drawable), setPageMarginDrawable(int)

  • getPageMargin

    public int getPageMargin()

    Return the margin between pages.

    Returns:

    The size of the margin in pixels

  • setPageMarginDrawable

    public void setPageMarginDrawable(Drawable d)

    Set a drawable that will be used to fill the margin between pages.

    Parameters:

    d - Drawable to display between pages

  • setPageMarginDrawable

    public void setPageMarginDrawable(int resId)

    Set a drawable that will be used to fill the margin between pages.

    Parameters:

    resId - Resource ID of a drawable to display between pages

  • verifyDrawable

    protected boolean verifyDrawable(Drawable who)

    Description copied from class: View
    If your view subclass is displaying its own Drawable objects, it should override this function and return true for any Drawable it is displaying. This allows animations for those drawables to be scheduled.

    Be sure to call through to the super class when overriding this function.

    Overrides:

    verifyDrawable in class View

    Parameters:

    who - The Drawable to verify. Return true if it is one you are displaying, else return the result of calling through to the super class.

    Returns:

    boolean If true than the Drawable is being displayed in the view; else false and it is not allowed to animate.

    See Also:

    View.unscheduleDrawable(android.graphics.drawable.Drawable), View.drawableStateChanged()

  • drawableStateChanged

    protected void drawableStateChanged()

    Description copied from class: View
    This function is called whenever the state of the view changes in such a way that it impacts the state of drawables being shown.

    Be sure to call through to the superclass when overriding this function.

    Overrides:

    drawableStateChanged in class ViewGroup

    See Also:

    Drawable.setState(int[])

  • onSaveInstanceState

    public Parcelable onSaveInstanceState()

    Description copied from class: View
    Hook allowing a view to generate a representation of its internal state that can later be used to create a new instance with that same state. This state should only contain information that is not persistent or can not be reconstructed later. For example, you will never store your current position on screen because that will be computed again when a new instance of the view is placed in its view hierarchy.

    Some examples of things you may store here: the current cursor position in a text view (but usually not the text itself since that is stored in a content provider or other persistent storage), the currently selected item in a list view.

    Overrides:

    onSaveInstanceState in class View

    Returns:

    Returns a Parcelable object containing the view's current dynamic state, or null if there is nothing interesting to save. The default implementation returns null.

    See Also:

    View.onRestoreInstanceState(android.os.Parcelable), View.saveHierarchyState(android.util.SparseArray), View.dispatchSaveInstanceState(android.util.SparseArray), View.setSaveEnabled(boolean)

  • onRestoreInstanceState

    public void onRestoreInstanceState(Parcelable state)

    Description copied from class: View
    Hook allowing a view to re-apply a representation of its internal state that had previously been generated by View.onSaveInstanceState(). This function will never be called with a null state.

    Overrides:

    onRestoreInstanceState in class View

    Parameters:

    state - The frozen state that had previously been returned by View.onSaveInstanceState().

    See Also:

    View.onSaveInstanceState(), View.restoreHierarchyState(android.util.SparseArray), View.dispatchRestoreInstanceState(android.util.SparseArray)

  • addView

    public void addView(View child,
               int index,
               ViewGroup.LayoutParams params)

    Description copied from class: ViewGroup
    Adds a child view with the specified layout parameters.

    Note: do not invoke this method from View.draw(android.graphics.Canvas), View.onDraw(android.graphics.Canvas), ViewGroup.dispatchDraw(android.graphics.Canvas) or any related method.

    Overrides:

    addView in class ViewGroup

    Parameters:

    child - the child view to add

    index - the position at which to add the child

    params - the layout parameters to set on the child

  • onAttachedToWindow

    protected void onAttachedToWindow()

    Description copied from class: View
    This is called when the view is attached to a window. At this point it has a Surface and will start drawing. Note that this function is guaranteed to be called before View.onDraw(android.graphics.Canvas), however it may be called any time before the first onDraw -- including before or after View.onMeasure(int, int).

    Overrides:

    onAttachedToWindow in class View

    See Also:

    View.onDetachedFromWindow()

  • onMeasure

    protected void onMeasure(int widthMeasureSpec,
                 int heightMeasureSpec)

    Description copied from class: View

    Measure the view and its content to determine the measured width and the measured height. This method is invoked by View.measure(int, int) and should be overriden by subclasses to provide accurate and efficient measurement of their contents.

    CONTRACT: When overriding this method, you must call View.setMeasuredDimension(int, int) to store the measured width and height of this view. Failure to do so will trigger an IllegalStateException, thrown by View.measure(int, int). Calling the superclass' View.onMeasure(int, int) is a valid use.

    The base class implementation of measure defaults to the background size, unless a larger size is allowed by the MeasureSpec. Subclasses should override View.onMeasure(int, int) to provide better measurements of their content.

    If this method is overridden, it is the subclass's responsibility to make sure the measured height and width are at least the view's minimum height and width (View.getSuggestedMinimumHeight() and View.getSuggestedMinimumWidth()).

    Overrides:

    onMeasure in class View

    Parameters:

    widthMeasureSpec - horizontal space requirements as imposed by the parent. The requirements are encoded with View.MeasureSpec.

    heightMeasureSpec - vertical space requirements as imposed by the parent. The requirements are encoded with View.MeasureSpec.

    See Also:

    View.getMeasuredWidth(), View.getMeasuredHeight(), View.setMeasuredDimension(int, int), View.getSuggestedMinimumHeight(), View.getSuggestedMinimumWidth(), View.MeasureSpec.getMode(int), View.MeasureSpec.getSize(int)

  • onSizeChanged

    protected void onSizeChanged(int w,
                     int h,
                     int oldw,
                     int oldh)

    Description copied from class: View
    This is called during layout when the size of this view has changed. If you were just added to the view hierarchy, you're called with the old values of 0.

    Overrides:

    onSizeChanged in class View

    Parameters:

    w - Current width of this view.

    h - Current height of this view.

    oldw - Old width of this view.

    oldh - Old height of this view.

  • onLayout

    protected void onLayout(boolean changed,
                int l,
                int t,
                int r,
                int b)

    Description copied from class: ViewGroup
    Called from layout when this view should assign a size and position to each of its children. Derived classes with children should override this method and call layout on each of their children.

    Specified by:

    onLayout in class ViewGroup

    Parameters:

    changed - This is a new size or position for this view

    l - Left position, relative to parent

    t - Top position, relative to parent

    r - Right position, relative to parent

    b - Bottom position, relative to parent

  • computeScroll

    public void computeScroll()

    Description copied from class: View
    Called by a parent to request that a child update its values for mScrollX and mScrollY if necessary. This will typically be done if the child is animating a scroll using a Scroller object.

    Overrides:

    computeScroll in class View

  • onPageScrolled

    protected void onPageScrolled(int position,
                      float offset,
                      int offsetPixels)

    This method will be invoked when the current page is scrolled, either as part of a programmatically initiated smooth scroll or a user initiated touch scroll. If you override this method you must call through to the superclass implementation (e.g. super.onPageScrolled(position, offset, offsetPixels)) before onPageScrolled returns.

    Parameters:

    position - Position index of the first page currently being displayed. Page position+1 will be visible if positionOffset is nonzero.

    offset - Value from [0, 1) indicating the offset from the page at position.

    offsetPixels - Value in pixels indicating the offset from position.

  • onInterceptTouchEvent

    public boolean onInterceptTouchEvent(MotionEvent ev)

    Description copied from class: ViewGroup
    Implement this method to intercept all touch screen motion events. This allows you to watch events as they are dispatched to your children, and take ownership of the current gesture at any point.

    Using this function takes some care, as it has a fairly complicated interaction with View.onTouchEvent(MotionEvent), and using it requires implementing that method as well as this one in the correct way. Events will be received in the following order:

    1. You will receive the down event here.
    2. The down event will be handled either by a child of this view group, or given to your own onTouchEvent() method to handle; this means you should implement onTouchEvent() to return true, so you will continue to see the rest of the gesture (instead of looking for a parent view to handle it). Also, by returning true from onTouchEvent(), you will not receive any following events in onInterceptTouchEvent() and all touch processing must happen in onTouchEvent() like normal.
    3. For as long as you return false from this function, each following event (up to and including the final up) will be delivered first here and then to the target's onTouchEvent().
    4. If you return true from here, you will not receive any following events: the target view will receive the same event but with the action MotionEvent.ACTION_CANCEL, and all further events will be delivered to your onTouchEvent() method and no longer appear here.

    Overrides:

    onInterceptTouchEvent in class ViewGroup

    Parameters:

    ev - The motion event being dispatched down the hierarchy.

    Returns:

    Return true to steal motion events from the children and have them dispatched to this ViewGroup through onTouchEvent(). The current target will receive an ACTION_CANCEL event, and no further messages will be delivered here.

  • onTouchEvent

    public boolean onTouchEvent(MotionEvent ev)

    Description copied from class: View
    Implement this method to handle touch screen motion events.

    Overrides:

    onTouchEvent in class View

    Parameters:

    ev - The motion event.

    Returns:

    True if the event was handled, false otherwise.

  • draw

    public void draw(Canvas canvas)

    Description copied from class: View
    Manually render this view (and all of its children) to the given Canvas. The view must have already done a full layout before this function is called. When implementing a view, implement View.onDraw(android.graphics.Canvas) instead of overriding this method. If you do need to override this method, call the superclass version.

    Overrides:

    draw in class View

    Parameters:

    canvas - The Canvas to which the View is rendered.

  • onDraw

    protected void onDraw(Canvas canvas)

    Description copied from class: View
    Implement this to do your drawing.

    Overrides:

    onDraw in class View

    Parameters:

    canvas - the canvas on which the background will be drawn

  • beginFakeDrag

    public boolean beginFakeDrag()

    Start a fake drag of the pager.

    A fake drag can be useful if you want to synchronize the motion of the ViewPager with the touch scrolling of another view, while still letting the ViewPager control the snapping motion and fling behavior. (e.g. parallax-scrolling tabs.) Call fakeDragBy(float) to simulate the actual drag motion. Call endFakeDrag() to complete the fake drag and fling as necessary.

    During a fake drag the ViewPager will ignore all touch events. If a real drag is already in progress, this method will return false.

    Returns:

    true if the fake drag began successfully, false if it could not be started.

    See Also:

    fakeDragBy(float), endFakeDrag()

  • endFakeDrag

    public void endFakeDrag()

    End a fake drag of the pager.

    See Also:

    beginFakeDrag(), fakeDragBy(float)

  • fakeDragBy

    public void fakeDragBy(float xOffset)

    Fake drag by an offset in pixels. You must have called beginFakeDrag() first.

    Parameters:

    xOffset - Offset in pixels to drag by.

    See Also:

    beginFakeDrag(), endFakeDrag()

  • isFakeDragging

    public boolean isFakeDragging()

    Returns true if a fake drag is in progress.

    Returns:

    true if currently in a fake drag, false otherwise.

    See Also:

    beginFakeDrag(), fakeDragBy(float), endFakeDrag()

  • canScroll

    protected boolean canScroll(View v,
                    boolean checkV,
                    int dx,
                    int x,
                    int y)

    Tests scrollability within child views of v given a delta of dx.

    Parameters:

    v - View to test for horizontal scrollability

    checkV - Whether the view v passed should itself be checked for scrollability (true), or just its children (false).

    dx - Delta scrolled in pixels

    x - X coordinate of the active touch point

    y - Y coordinate of the active touch point

    Returns:

    true if child views of v can be scrolled by delta of dx.

  • dispatchKeyEvent

    public boolean dispatchKeyEvent(KeyEvent event)

    Description copied from class: ViewGroup
    Dispatch a key event to the next view on the focus path. This path runs from the top of the view tree down to the currently focused view. If this view has focus, it will dispatch to itself. Otherwise it will dispatch the next node down the focus path. This method also fires any key listeners.

    Overrides:

    dispatchKeyEvent in class ViewGroup

    Parameters:

    event - The key event to be dispatched.

    Returns:

    True if the event was handled, false otherwise.

  • executeKeyEvent

    public boolean executeKeyEvent(KeyEvent event)

    You can call this function yourself to have the scroll view perform scrolling from a key event, just as if the event had been dispatched to it by the view hierarchy.

    Parameters:

    event - The key event to execute.

    Returns:

    Return true if the event was handled, else false.

  • arrowScroll

    public boolean arrowScroll(int direction)

  • addFocusables

    public void addFocusables(ArrayList<View> views,
                     int direction,
                     int focusableMode)

    We only want the current page that is being shown to be focusable.

    Overrides:

    addFocusables in class ViewGroup

    Parameters:

    views - Focusable views found so far or null if all we are interested is the number of focusables.

    direction - The direction of the focus.

    focusableMode - The type of focusables to be added.

    See Also:

    View.FOCUSABLES_ALL, View.FOCUSABLES_TOUCH_MODE

  • addTouchables

    public void addTouchables(ArrayList<View> views)

    We only want the current page that is being shown to be touchable.

    Overrides:

    addTouchables in class ViewGroup

    Parameters:

    views - Touchable views found so far

  • onRequestFocusInDescendants

    protected boolean onRequestFocusInDescendants(int direction,
                                      Rect previouslyFocusedRect)

    We only want the current page that is being shown to be focusable.

    Overrides:

    onRequestFocusInDescendants in class ViewGroup

    Parameters:

    direction - One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT

    previouslyFocusedRect - The rectangle (in this View's coordinate system) to give a finer grained hint about where focus is coming from. May be null if there is no hint.

    Returns:

    Whether focus was taken.

  • dispatchPopulateAccessibilityEvent

    public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event)

    Description copied from class: View
    Dispatches an AccessibilityEvent to the View first and then to its children for adding their text content to the event. Note that the event text is populated in a separate dispatch path since we add to the event not only the text of the source but also the text of all its descendants. A typical implementation will call View.onPopulateAccessibilityEvent(AccessibilityEvent) on the this view and then call the View.dispatchPopulateAccessibilityEvent(AccessibilityEvent) on each child. Override this method if custom population of the event text content is required.

    If an View.AccessibilityDelegate has been specified via calling View.setAccessibilityDelegate(AccessibilityDelegate) its View.AccessibilityDelegate.dispatchPopulateAccessibilityEvent(View, AccessibilityEvent) is responsible for handling this call.

    Note: Accessibility events of certain types are not dispatched for populating the event text via this method. For details refer to AccessibilityEvent.

    Overrides:

    dispatchPopulateAccessibilityEvent in class View

    Parameters:

    event - The event.

    Returns:

    True if the event population was completed.

  • generateDefaultLayoutParams

    protected ViewGroup.LayoutParams generateDefaultLayoutParams()

    Description copied from class: ViewGroup
    Returns a set of default layout parameters. These parameters are requested when the View passed to ViewGroup.addView(View) has no layout parameters already set. If null is returned, an exception is thrown from addView.

    Overrides:

    generateDefaultLayoutParams in class ViewGroup

    Returns:

    a set of default layout parameters or null

  • generateLayoutParams

    protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p)

    Description copied from class: ViewGroup
    Returns a safe set of layout parameters based on the supplied layout params. When a ViewGroup is passed a View whose layout params do not pass the test of ViewGroup.checkLayoutParams(android.view.ViewGroup.LayoutParams), this method is invoked. This method should return a new set of layout params suitable for this ViewGroup, possibly by copying the appropriate attributes from the specified set of layout params.

    Overrides:

    generateLayoutParams in class ViewGroup

    Parameters:

    p - The layout parameters to convert into a suitable set of layout parameters for this ViewGroup.

    Returns:

    an instance of ViewGroup.LayoutParams or one of its descendants

  • checkLayoutParams

    protected boolean checkLayoutParams(ViewGroup.LayoutParams p)

    Description copied from class: ViewGroup

    Overrides:

    checkLayoutParams in class ViewGroup

  • generateLayoutParams

    public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs)

    Description copied from class: ViewGroup
    Returns a new set of layout parameters based on the supplied attributes set.

    Overrides:

    generateLayoutParams in class ViewGroup

    Parameters:

    attrs - the attributes to build the layout parameters from

    Returns:

    an instance of ViewGroup.LayoutParams or one of its descendants