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FragmentManager

public abstract class FragmentManager
extends Object

java.lang.Object
   ↳ android.support.v4.app.FragmentManager


Static library support version of the framework's FragmentManager. Used to write apps that run on platforms prior to Android 3.0. When running on Android 3.0 or above, this implementation is still used; it does not try to switch to the framework's implementation. See the framework FragmentManager documentation for a class overview.

Your activity must derive from FragmentActivity to use this. From such an activity, you can acquire the FragmentManager by calling getSupportFragmentManager().

Summary

Nested classes

interface FragmentManager.BackStackEntry

Representation of an entry on the fragment back stack, as created with FragmentTransaction.addToBackStack()

interface FragmentManager.OnBackStackChangedListener

Interface to watch for changes to the back stack. 

Constants

int POP_BACK_STACK_INCLUSIVE

Flag for popBackStack(String, int) and popBackStack(int, int): If set, and the name or ID of a back stack entry has been supplied, then all matching entries will be consumed until one that doesn't match is found or the bottom of the stack is reached.

Public constructors

FragmentManager()

Public methods

abstract void addOnBackStackChangedListener(FragmentManager.OnBackStackChangedListener listener)

Add a new listener for changes to the fragment back stack.

abstract FragmentTransaction beginTransaction()

Start a series of edit operations on the Fragments associated with this FragmentManager.

abstract void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args)

Print the FragmentManager's state into the given stream.

static void enableDebugLogging(boolean enabled)

Control whether the framework's internal fragment manager debugging logs are turned on.

abstract boolean executePendingTransactions()

After a FragmentTransaction is committed with FragmentTransaction.commit(), it is scheduled to be executed asynchronously on the process's main thread.

abstract Fragment findFragmentById(int id)

Finds a fragment that was identified by the given id either when inflated from XML or as the container ID when added in a transaction.

abstract Fragment findFragmentByTag(String tag)

Finds a fragment that was identified by the given tag either when inflated from XML or as supplied when added in a transaction.

abstract FragmentManager.BackStackEntry getBackStackEntryAt(int index)

Return the BackStackEntry at index index in the back stack; entries start index 0 being the bottom of the stack.

abstract int getBackStackEntryCount()

Return the number of entries currently in the back stack.

abstract Fragment getFragment(Bundle bundle, String key)

Retrieve the current Fragment instance for a reference previously placed with putFragment(Bundle, String, Fragment).

abstract boolean isDestroyed()

Returns true if the final Activity.onDestroy() call has been made on the FragmentManager's Activity, so this instance is now dead.

abstract void popBackStack()

Pop the top state off the back stack.

abstract void popBackStack(int id, int flags)

Pop all back stack states up to the one with the given identifier.

abstract void popBackStack(String name, int flags)

Pop the last fragment transition from the manager's fragment back stack.

abstract boolean popBackStackImmediate(int id, int flags)

Like popBackStack(int, int), but performs the operation immediately inside of the call.

abstract boolean popBackStackImmediate(String name, int flags)

Like popBackStack(String, int), but performs the operation immediately inside of the call.

abstract boolean popBackStackImmediate()

Like popBackStack(), but performs the operation immediately inside of the call.

abstract void putFragment(Bundle bundle, String key, Fragment fragment)

Put a reference to a fragment in a Bundle.

abstract void removeOnBackStackChangedListener(FragmentManager.OnBackStackChangedListener listener)

Remove a listener that was previously added with addOnBackStackChangedListener(OnBackStackChangedListener).

abstract Fragment.SavedState saveFragmentInstanceState(Fragment f)

Save the current instance state of the given Fragment.

Inherited methods

From class java.lang.Object

Constants

POP_BACK_STACK_INCLUSIVE

int POP_BACK_STACK_INCLUSIVE

Flag for popBackStack(String, int) and popBackStack(int, int): If set, and the name or ID of a back stack entry has been supplied, then all matching entries will be consumed until one that doesn't match is found or the bottom of the stack is reached. Otherwise, all entries up to but not including that entry will be removed.

Constant Value: 1 (0x00000001)

Public constructors

FragmentManager

FragmentManager ()

Public methods

addOnBackStackChangedListener

void addOnBackStackChangedListener (FragmentManager.OnBackStackChangedListener listener)

Add a new listener for changes to the fragment back stack.

Parameters
listener FragmentManager.OnBackStackChangedListener

beginTransaction

FragmentTransaction beginTransaction ()

Start a series of edit operations on the Fragments associated with this FragmentManager.

Note: A fragment transaction can only be created/committed prior to an activity saving its state. If you try to commit a transaction after FragmentActivity.onSaveInstanceState() (and prior to a following FragmentActivity.onStart or FragmentActivity.onResume(), you will get an error. This is because the framework takes care of saving your current fragments in the state, and if changes are made after the state is saved then they will be lost.

Returns
FragmentTransaction

dump

void dump (String prefix, 
                FileDescriptor fd, 
                PrintWriter writer, 
                String[] args)

Print the FragmentManager's state into the given stream.

Parameters
prefix String: Text to print at the front of each line.
fd FileDescriptor: The raw file descriptor that the dump is being sent to.
writer PrintWriter: A PrintWriter to which the dump is to be set.
args String: Additional arguments to the dump request.

enableDebugLogging

void enableDebugLogging (boolean enabled)

Control whether the framework's internal fragment manager debugging logs are turned on. If enabled, you will see output in logcat as the framework performs fragment operations.

Parameters
enabled boolean

executePendingTransactions

boolean executePendingTransactions ()

After a FragmentTransaction is committed with FragmentTransaction.commit(), it is scheduled to be executed asynchronously on the process's main thread. If you want to immediately executing any such pending operations, you can call this function (only from the main thread) to do so. Note that all callbacks and other related behavior will be done from within this call, so be careful about where this is called from.

If you are committing a single transaction that does not modify the fragment back stack, strongly consider using commitNow() instead. This can help avoid unwanted side effects when other code in your app has pending committed transactions that expect different timing.

Returns
boolean Returns true if there were any pending transactions to be executed.

findFragmentById

Fragment findFragmentById (int id)

Finds a fragment that was identified by the given id either when inflated from XML or as the container ID when added in a transaction. This first searches through fragments that are currently added to the manager's activity; if no such fragment is found, then all fragments currently on the back stack associated with this ID are searched.

Parameters
id int
Returns
Fragment The fragment if found or null otherwise.

findFragmentByTag

Fragment findFragmentByTag (String tag)

Finds a fragment that was identified by the given tag either when inflated from XML or as supplied when added in a transaction. This first searches through fragments that are currently added to the manager's activity; if no such fragment is found, then all fragments currently on the back stack are searched.

Parameters
tag String
Returns
Fragment The fragment if found or null otherwise.

getBackStackEntryAt

FragmentManager.BackStackEntry getBackStackEntryAt (int index)

Return the BackStackEntry at index index in the back stack; entries start index 0 being the bottom of the stack.

Parameters
index int
Returns
FragmentManager.BackStackEntry

getBackStackEntryCount

int getBackStackEntryCount ()

Return the number of entries currently in the back stack.

Returns
int

getFragment

Fragment getFragment (Bundle bundle, 
                String key)

Retrieve the current Fragment instance for a reference previously placed with putFragment(Bundle, String, Fragment).

Parameters
bundle Bundle: The bundle from which to retrieve the fragment reference.
key String: The name of the entry in the bundle.
Returns
Fragment Returns the current Fragment instance that is associated with the given reference.

isDestroyed

boolean isDestroyed ()

Returns true if the final Activity.onDestroy() call has been made on the FragmentManager's Activity, so this instance is now dead.

Returns
boolean

popBackStack

void popBackStack ()

Pop the top state off the back stack. Returns true if there was one to pop, else false. This function is asynchronous -- it enqueues the request to pop, but the action will not be performed until the application returns to its event loop.

popBackStack

void popBackStack (int id, 
                int flags)

Pop all back stack states up to the one with the given identifier. This function is asynchronous -- it enqueues the request to pop, but the action will not be performed until the application returns to its event loop.

Parameters
id int: Identifier of the stated to be popped. If no identifier exists, false is returned. The identifier is the number returned by FragmentTransaction.commit(). The POP_BACK_STACK_INCLUSIVE flag can be used to control whether the named state itself is popped.
flags int: Either 0 or POP_BACK_STACK_INCLUSIVE.

popBackStack

void popBackStack (String name, 
                int flags)

Pop the last fragment transition from the manager's fragment back stack. If there is nothing to pop, false is returned. This function is asynchronous -- it enqueues the request to pop, but the action will not be performed until the application returns to its event loop.

Parameters
name String: If non-null, this is the name of a previous back state to look for; if found, all states up to that state will be popped. The POP_BACK_STACK_INCLUSIVE flag can be used to control whether the named state itself is popped. If null, only the top state is popped.
flags int: Either 0 or POP_BACK_STACK_INCLUSIVE.

popBackStackImmediate

boolean popBackStackImmediate (int id, 
                int flags)

Like popBackStack(int, int), but performs the operation immediately inside of the call. This is like calling executePendingTransactions() afterwards.

Parameters
id int
flags int
Returns
boolean Returns true if there was something popped, else false.

popBackStackImmediate

boolean popBackStackImmediate (String name, 
                int flags)

Like popBackStack(String, int), but performs the operation immediately inside of the call. This is like calling executePendingTransactions() afterwards.

Parameters
name String
flags int
Returns
boolean Returns true if there was something popped, else false.

popBackStackImmediate

boolean popBackStackImmediate ()

Like popBackStack(), but performs the operation immediately inside of the call. This is like calling executePendingTransactions() afterwards.

Returns
boolean Returns true if there was something popped, else false.

putFragment

void putFragment (Bundle bundle, 
                String key, 
                Fragment fragment)

Put a reference to a fragment in a Bundle. This Bundle can be persisted as saved state, and when later restoring getFragment(Bundle, String) will return the current instance of the same fragment.

Parameters
bundle Bundle: The bundle in which to put the fragment reference.
key String: The name of the entry in the bundle.
fragment Fragment: The Fragment whose reference is to be stored.

removeOnBackStackChangedListener

void removeOnBackStackChangedListener (FragmentManager.OnBackStackChangedListener listener)

Remove a listener that was previously added with addOnBackStackChangedListener(OnBackStackChangedListener).

Parameters
listener FragmentManager.OnBackStackChangedListener

saveFragmentInstanceState

Fragment.SavedState saveFragmentInstanceState (Fragment f)

Save the current instance state of the given Fragment. This can be used later when creating a new instance of the Fragment and adding it to the fragment manager, to have it create itself to match the current state returned here. Note that there are limits on how this can be used:

  • The Fragment must currently be attached to the FragmentManager.
  • A new Fragment created using this saved state must be the same class type as the Fragment it was created from.
  • The saved state can not contain dependencies on other fragments -- that is it can't use putFragment(Bundle, String, Fragment) to store a fragment reference because that reference may not be valid when this saved state is later used. Likewise the Fragment's target and result code are not included in this state.

Parameters
f Fragment: The Fragment whose state is to be saved.
Returns
Fragment.SavedState The generated state. This will be null if there was no interesting state created by the fragment.

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