public class DialogFragment extends Fragment implements DialogInterface.OnCancelListener, DialogInterface.OnDismissListener
Implementations should override this class and implement
Fragment.onCreateView(LayoutInflater, ViewGroup, Bundle)
to supply the
content of the dialog. Alternatively, they can override
onCreateDialog(Bundle)
to create an entirely custom dialog, such
as an AlertDialog, with its own content.
Topics covered here:
DialogFragment does various things to keep the fragment's lifecycle driving it, instead of the Dialog. Note that dialogs are generally autonomous entities -- they are their own window, receiving their own input events, and often deciding on their own when to disappear (by receiving a back key event or the user clicking on a button).
DialogFragment needs to ensure that what is happening with the Fragment
and Dialog states remains consistent. To do this, it watches for dismiss
events from the dialog and takes care of removing its own state when they
happen. This means you should use show(FragmentManager, String)
or show(FragmentTransaction, String)
to add an instance of
DialogFragment to your UI, as these keep track of how DialogFragment should
remove itself when the dialog is dismissed.
The simplest use of DialogFragment is as a floating container for the fragment's view hierarchy. A simple implementation may look like this:
An example showDialog() method on the Activity could be:
This removes any currently shown dialog, creates a new DialogFragment with an argument, and shows it as a new state on the back stack. When the transaction is popped, the current DialogFragment and its Dialog will be destroyed, and the previous one (if any) re-shown. Note that in this case DialogFragment will take care of popping the transaction of the Dialog is dismissed separately from it.
Instead of (or in addition to) implementing Fragment.onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)
to
generate the view hierarchy inside of a dialog, you may implement
onCreateDialog(Bundle)
to create your own custom Dialog object.
This is most useful for creating an AlertDialog
, allowing you
to display standard alerts to the user that are managed by a fragment.
A simple example implementation of this is:
The activity creating this fragment may have the following methods to show the dialog and receive results from it:
Note that in this case the fragment is not placed on the back stack, it is just added as an indefinitely running fragment. Because dialogs normally are modal, this will still operate as a back stack, since the dialog will capture user input until it is dismissed. When it is dismissed, DialogFragment will take care of removing itself from its fragment manager.
A DialogFragment can still optionally be used as a normal fragment, if
desired. This is useful if you have a fragment that in some cases should
be shown as a dialog and others embedded in a larger UI. This behavior
will normally be automatically selected for you based on how you are using
the fragment, but can be customized with setShowsDialog(boolean)
.
For example, here is a simple dialog fragment:
An instance of this fragment can be created and shown as a dialog:
It can also be added as content in a view hierarchy:
Fragment.InstantiationException, Fragment.SavedState
Modifier and Type | Field and Description |
---|---|
static int |
STYLE_NO_FRAME
Style for
setStyle(int, int) : don't draw
any frame at all; the view hierarchy returned by Fragment.onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)
is entirely responsible for drawing the dialog. |
static int |
STYLE_NO_INPUT
Style for
setStyle(int, int) : like
STYLE_NO_FRAME , but also disables all input to the dialog. |
static int |
STYLE_NO_TITLE
Style for
setStyle(int, int) : don't include
a title area. |
static int |
STYLE_NORMAL
Style for
setStyle(int, int) : a basic,
normal dialog. |
TRIM_MEMORY_BACKGROUND, TRIM_MEMORY_COMPLETE, TRIM_MEMORY_MODERATE, TRIM_MEMORY_RUNNING_CRITICAL, TRIM_MEMORY_RUNNING_LOW, TRIM_MEMORY_RUNNING_MODERATE, TRIM_MEMORY_UI_HIDDEN
Constructor and Description |
---|
DialogFragment() |
Modifier and Type | Method and Description |
---|---|
void |
dismiss()
Dismiss the fragment and its dialog.
|
void |
dismissAllowingStateLoss()
Version of
dismiss() that uses
FragmentTransaction.commitAllowingStateLoss() . |
void |
dump(String prefix,
FileDescriptor fd,
PrintWriter writer,
String[] args)
Print the Fragments's state into the given stream.
|
Dialog |
getDialog() |
LayoutInflater |
getLayoutInflater(Bundle savedInstanceState) |
boolean |
getShowsDialog()
Return the current value of
setShowsDialog(boolean) . |
int |
getTheme() |
boolean |
isCancelable()
Return the current value of
setCancelable(boolean) . |
void |
onActivityCreated(Bundle savedInstanceState)
Called when the fragment's activity has been created and this
fragment's view hierarchy instantiated.
|
void |
onAttach(Activity activity)
Called when a fragment is first attached to its activity.
|
void |
onCancel(DialogInterface dialog)
This method will be invoked when the dialog is canceled.
|
void |
onCreate(Bundle savedInstanceState)
Called to do initial creation of a fragment.
|
Dialog |
onCreateDialog(Bundle savedInstanceState)
Override to build your own custom Dialog container.
|
void |
onDestroyView()
Remove dialog.
|
void |
onDetach()
Called when the fragment is no longer attached to its activity.
|
void |
onDismiss(DialogInterface dialog)
This method will be invoked when the dialog is dismissed.
|
void |
onSaveInstanceState(Bundle outState)
Called to ask the fragment to save its current dynamic state, so it
can later be reconstructed in a new instance of its process is
restarted.
|
void |
onStart()
Called when the Fragment is visible to the user.
|
void |
onStop()
Called when the Fragment is no longer started.
|
void |
setCancelable(boolean cancelable)
Control whether the shown Dialog is cancelable.
|
void |
setShowsDialog(boolean showsDialog)
Controls whether this fragment should be shown in a dialog.
|
void |
setStyle(int style,
int theme)
Call to customize the basic appearance and behavior of the
fragment's dialog.
|
void |
show(FragmentManager manager,
String tag)
Display the dialog, adding the fragment to the given FragmentManager.
|
int |
show(FragmentTransaction transaction,
String tag)
Display the dialog, adding the fragment using an existing transaction
and then committing the transaction.
|
equals, getActivity, getArguments, getChildFragmentManager, getFragmentManager, getId, getLoaderManager, getParentFragment, getResources, getRetainInstance, getString, getString, getTag, getTargetFragment, getTargetRequestCode, getText, getUserVisibleHint, getView, hashCode, instantiate, instantiate, isAdded, isDetached, isHidden, isInLayout, isRemoving, isResumed, isVisible, onActivityResult, onConfigurationChanged, onContextItemSelected, onCreateAnimator, onCreateContextMenu, onCreateOptionsMenu, onCreateView, onDestroy, onDestroyOptionsMenu, onHiddenChanged, onInflate, onInflate, onLowMemory, onOptionsItemSelected, onOptionsMenuClosed, onPause, onPrepareOptionsMenu, onResume, onTrimMemory, onViewCreated, onViewStateRestored, registerForContextMenu, setArguments, setHasOptionsMenu, setInitialSavedState, setMenuVisibility, setRetainInstance, setTargetFragment, setUserVisibleHint, startActivity, startActivity, startActivityForResult, startActivityForResult, toString, unregisterForContextMenu
public static final int STYLE_NORMAL
setStyle(int, int)
: a basic,
normal dialog.public static final int STYLE_NO_TITLE
setStyle(int, int)
: don't include
a title area.public static final int STYLE_NO_FRAME
setStyle(int, int)
: don't draw
any frame at all; the view hierarchy returned by Fragment.onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)
is entirely responsible for drawing the dialog.public static final int STYLE_NO_INPUT
setStyle(int, int)
: like
STYLE_NO_FRAME
, but also disables all input to the dialog.
The user can not touch it, and its window will not receive input focus.public void setStyle(int style, int theme)
style
- Selects a standard style: may be STYLE_NORMAL
,
STYLE_NO_TITLE
, STYLE_NO_FRAME
, or
STYLE_NO_INPUT
.theme
- Optional custom theme. If 0, an appropriate theme (based
on the style) will be selected for you.public void show(FragmentManager manager, String tag)
manager
- The FragmentManager this fragment will be added to.tag
- The tag for this fragment, as per
FragmentTransaction.add
.public int show(FragmentTransaction transaction, String tag)
transaction
- An existing transaction in which to add the fragment.tag
- The tag for this fragment, as per
FragmentTransaction.add
.FragmentTransaction.commit()
.public void dismiss()
public void dismissAllowingStateLoss()
dismiss()
that uses
FragmentTransaction.commitAllowingStateLoss()
. See linked
documentation for further details.public Dialog getDialog()
public int getTheme()
public void setCancelable(boolean cancelable)
Dialog.setCancelable(boolean)
, because DialogFragment needs to change
its behavior based on this.cancelable
- If true, the dialog is cancelable. The default
is true.public boolean isCancelable()
setCancelable(boolean)
.public void setShowsDialog(boolean showsDialog)
onActivityCreated(Bundle)
,
and the fragment's view hierarchy will thus not be added to it. This
allows you to instead use it as a normal fragment (embedded inside of
its activity).
This is normally set for you based on whether the fragment is
associated with a container view ID passed to
FragmentTransaction.add(int, Fragment)
.
If the fragment was added with a container, setShowsDialog will be
initialized to false; otherwise, it will be true.
showsDialog
- If true, the fragment will be displayed in a Dialog.
If false, no Dialog will be created and the fragment's view hierarchly
left undisturbed.public boolean getShowsDialog()
setShowsDialog(boolean)
.public void onAttach(Activity activity)
Fragment
Fragment.onCreate(Bundle)
will be called after this.public void onDetach()
Fragment
Fragment.onDestroy()
.public void onCreate(Bundle savedInstanceState)
Fragment
Fragment.onAttach(Activity)
and before
Fragment.onCreateView(LayoutInflater, ViewGroup, Bundle)
.
Note that this can be called while the fragment's activity is
still in the process of being created. As such, you can not rely
on things like the activity's content view hierarchy being initialized
at this point. If you want to do work once the activity itself is
created, see Fragment.onActivityCreated(Bundle)
.
public LayoutInflater getLayoutInflater(Bundle savedInstanceState)
getLayoutInflater
in class Fragment
public Dialog onCreateDialog(Bundle savedInstanceState)
Fragment.onCreateView(LayoutInflater, ViewGroup, Bundle)
does not need
to be implemented since the AlertDialog takes care of its own content.
This method will be called after onCreate(Bundle)
and
before Fragment.onCreateView(LayoutInflater, ViewGroup, Bundle)
. The
default implementation simply instantiates and returns a Dialog
class.
Note: DialogFragment own the Dialog.setOnCancelListener
and Dialog.setOnDismissListener
callbacks. You must not set them yourself.
To find out about these events, override onCancel(DialogInterface)
and onDismiss(DialogInterface)
.
savedInstanceState
- The last saved instance state of the Fragment,
or null if this is a freshly created Fragment.public void onCancel(DialogInterface dialog)
DialogInterface.OnCancelListener
onCancel
in interface DialogInterface.OnCancelListener
dialog
- The dialog that was canceled will be passed into the
method.public void onDismiss(DialogInterface dialog)
DialogInterface.OnDismissListener
onDismiss
in interface DialogInterface.OnDismissListener
dialog
- The dialog that was dismissed will be passed into the
method.public void onActivityCreated(Bundle savedInstanceState)
Fragment
Fragment.setRetainInstance(boolean)
to retain their instance,
as this callback tells the fragment when it is fully associated with
the new activity instance. This is called after Fragment.onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)
and before Fragment.onViewStateRestored(Bundle)
.onActivityCreated
in class Fragment
savedInstanceState
- If the fragment is being re-created from
a previous saved state, this is the state.public void onStart()
Fragment
Activity.onStart
of the containing
Activity's lifecycle.public void onSaveInstanceState(Bundle outState)
Fragment
Fragment.onCreate(Bundle)
,
Fragment.onCreateView(LayoutInflater, ViewGroup, Bundle)
, and
Fragment.onActivityCreated(Bundle)
.
This corresponds to Activity.onSaveInstanceState(Bundle)
and most of the discussion there
applies here as well. Note however: this method may be called
at any time before Fragment.onDestroy()
. There are many situations
where a fragment may be mostly torn down (such as when placed on the
back stack with no UI showing), but its state will not be saved until
its owning activity actually needs to save its state.
onSaveInstanceState
in class Fragment
outState
- Bundle in which to place your saved state.public void onStop()
Fragment
Activity.onStop
of the containing
Activity's lifecycle.public void onDestroyView()
onDestroyView
in class Fragment
public void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args)
Fragment
dump
in class Fragment
prefix
- Text to print at the front of each line.fd
- The raw file descriptor that the dump is being sent to.writer
- The PrintWriter to which you should dump your state. This will be
closed for you after you return.args
- additional arguments to the dump request.