An activity is a single, focused thing that the user can do. Almost all activities interact with the user, so the Activity class takes care of creating a window for you in which you can place your UI with setContentView(View). While activities are often presented to the user as full-screen windows, they can also be used in other ways: as floating windows (via a theme with windowIsFloating set) or embedded inside of another activity (using ActivityGroup). There are two methods almost all subclasses of Activity will implement:

• onCreate(Bundle) is where you initialize your activity. Most importantly, here you will usually call setContentView(int) with a layout resource defining your UI, and using findViewById(int) to retrieve the widgets in that UI that you need to interact with programmatically.
• onPause() is where you deal with the user leaving your activity. Most importantly, any changes made by the user should at this point be committed (usually to the ContentProvider holding the data).

To be of use with Context.startActivity(), all activity classes must have a corresponding <activity> declaration in their package's AndroidManifest.xml.

The Activity class is an important part of an application's overall lifecycle.

Topics covered here:

1. Activity Lifecycle
2. Configuration Changes
3. Starting Activities and Getting Results
4. Saving Persistent State
5. Permissions
6. Process Lifecycle

Activity Lifecycle

Activities in the system are managed as an activity stack. When a new activity is started, it is placed on the top of the stack and becomes the running activity -- the previous activity always remains below it in the stack, and will not come to the foreground again until the new activity exits.

An activity has essentially four states:

• If an activity is in the foreground of the screen (at the top of the stack), it is active or running.
• If an activity has lost focus but is still visible (that is, a new non-full-sized or transparent activity has focus on top of your activity), it is paused. A paused activity is completely alive (it maintains all state and member information and remains attached to the window manager), but can be killed by the system in extreme low memory situations.
• If an activity is completely obscured by another activity, it is stopped. It still retains all state and member information, however, it is no longer visible to the user so its window is hidden and it will often be killed by the system when memory is needed elsewhere.
• If an activity is paused or stopped, the system can drop the activity from memory by either asking it to finish, or simply killing its process. When it is displayed again to the user, it must be completely restarted and restored to its previous state.

The following diagram shows the important state paths of an Activity. The square rectangles represent callback methods you can implement to perform operations when the Activity moves between states. The colored ovals are major states the Activity can be in.

There are three key loops you may be interested in monitoring within your activity:

• The entire lifetime of an activity happens between the first call to onCreate(Bundle) through to a single final call to onDestroy(). An activity will do all setup of "global" state in onCreate(), and release all remaining resources in onDestroy(). For example, if it has a thread running in the background to download data from the network, it may create that thread in onCreate() and then stop the thread in onDestroy().
• The visible lifetime of an activity happens between a call to onStart() until a corresponding call to onStop(). During this time the user can see the activity on-screen, though it may not be in the foreground and interacting with the user. Between these two methods you can maintain resources that are needed to show the activity to the user. For example, you can register an IntentReceiver in onStart() to monitor for changes that impact your UI, and unregister it in onStop() when the user an no longer see what you are displaying. The onStart() and onStop() methods can be called multiple times, as the activity becomes visible and hidden to the user.
• The foreground lifetime of an activity happens between a call to onResume() until a corresponding call to onPause(). During this time the activity is in front of all other activities and interacting with the user. An activity can frequently go between the resumed and paused states -- for example when the device goes to sleep, when an activity result is delivered, or when a new intent is delivered -- so the code in these methods should be fairly lightweight.

The entire lifecycle of an activity is defined by the following Activity methods. All of these are hooks that you can override to do appropriate work when the activity changes state. All activities will implement onCreate(Bundle) to do their initial setup; many will also implement onPause() to commit changes to data and otherwise prepare to stop interacting with the user. Currently many activities must also implement onFreeze() and perform the corresponding state recovery in onCreate(Bundle), though we plan to add more facilities in the system that take care of these for the application. Other methods may be implemented as needed. You should always call up to your superclass when implementing these methods.

 public class Activity extends ApplicationContext {
     protected void onCreate(Bundle icicle);

     protected void onStart();
     
     protected void onRestart();

     protected void onResume();

     protected void onFreeze(Bundle outIcicle);

     protected void onPause();

     protected void onStop();

     protected void onDestroy();
 }
 

In general the movement through an activity's lifecycle looks like this:

Method			Description	Killable?	Next
onCreate()			Called when the activity is first created. This is where you should do all of your normal static set up: create views, bind data to lists, etc. This method also provides you with a Bundle containing the activity's previously frozen state, if there was one. Followed by onStart() if the activity is being first created, or onRestart() if it is being shown again after previously being stopped.	No	onResume()
	onRestart()		Called after your activity has been stopped, prior to it being started again. Always followed by onStart()	No	onResume()
	onStart()		Called when the activity is becoming visible to the user. Always followed by onResume().	No	onRestart() or onResume()
		onResume()	Called when the activity will start interacting with the user. At this point your activity is at the top of the activity stack, with user input going to it. Followed by either onFreeze() if another activity is being resumed in front of it, or onPause() if this activity is being finished.	No	onFreeze() or onPause()
		onFreeze()	Allows you to save away your current state, when your activity is being paused and another one resuming to interact with the user. After being paused, the system may at any time need to stop (or even outright kill) your application in order to claim resources for the current foreground activity. If this should happen, the state you supply here will later be given back to you onCreate() when a new instance of your activity is started to interact with the user. Always followed by onPause().	No	onPause()
		onPause()	Called when the system is about to start resuming a previous activity. This is typically used to commit unsaved changes to persistent data, stop animations and other things that may be consuming CPU, etc. Implementations of this method must be very quick because the next activity will not be resumed until this method returns. Followed by either onResume() if the activity returns back to the front, or onStop() if it becomes invisible to the user.	Yes	onResume() or onStop()
	onStop()		Called when the activity is no longer visible to the user, because another activity has been resumed and is covering this one. This may happen either because a new activity is being started, an existing one is being brought in front of this one, or this one is being destroyed. Followed by either onRestart() if this activity is coming back to interact with the user, or onDestroy() if this activity is going away.	Yes	onStart() or onDestroy()
onDestroy()			The final call you receive before your activity is destroyed. This can happen either because the activity is finishing (someone called finish() on it, or because the system is temporarily destroying this instance of the activity to save space. You can distinguish between these two scenarios with the isFinishing() method.	Yes	nothing

Note the "Killable" column in the above table -- for those methods that are marked as being killable, after that method returns the process hosting the activity may killed by the system at any time without another line of its code being executed. Thus you should take advantage of onFreeze() (for saving your current UI state) and onPause() (for writing any edits to persistent storage) so that the activity will be correctly restored to its current state in the event that it is killed. See the Process Lifecycle section for more information on how the lifecycle of a process is tied to the activities it is hosting.

For those methods that are not marked as being killable, the activity's process will not be killed by the system starting from the time the method is called and continuing after it returns. For example, an activity is in the killable state at the moment of onPause(), up until the start of onResume().

Configuration Changes

If the configuration of the device (as defined by the Resources.Configuration class) changes, then anything displaying a user interface will need to update to match that configuration. Because Activity is the primary mechanism for interacting with the user, it includes special support for handling configuration changes.

Unless you specify otherwise, a configuration change (such as a change in screen orientation, language, input devices, etc) will cause your current activity to be destroyed, going through the normal activity lifecycle process of onFreeze(Bundle), onPause(), onStop(), and onDestroy() as appropriate. If the activity had been in the foreground or visible to the user, once onDestroy() is called in that instance then a new instance of the activity will be created, with whatever icicle the previous instance had generated from onFreeze(Bundle).

This is done because any application resource, including layout files, can change based on any configuration value. Thus the only safe way to handle a configuration change is to re-retrieve all resources, including layouts, drawables, and strings. Because activities must already know how to save their state and re-create themselves from that state, this is a convenient way to have an activity restart itself with a new configuration.

In some special cases, you may want to bypass restarting your activity based on one or more types of configuration changes. This is done with the android:configChanges attribute in its manifest. For any type of configuration changes you say that you handle there, you will receive a call to your current activity's onConfigurationChanged(Resources.Configuration) method instead of being restarted. If a configuration change involves any that you do not handle, however, the activity will still be restarted and onConfigurationChanged(Resources.Configuration) will not be called.

Starting Activities and Getting Results

The startActivity(Intent) method is used to start a new activity, which will be placed at the top of the activity stack. It takes a single argument, an Intent, which describes the activity to be executed.

Sometimes you want to get a result back from an activity when it ends. For example, you may start an activity that lets the user pick a person in a list of contacts; when it ends, it returns the person that was selected. To do this, you call the startSubActivity(Intent, int) version with a second integer parameter identifying the call. The result will come back through your onActivityResult(int, int, String, Bundle) method.

When an activity exits, it can call setResult(int) to return data back to its parent. It must always supply a result code, which can be the standard results RESULT_CANCELED, RESULT_OK, or any custom values starting at RESULT_FIRST_USER. In addition, it can optionally return back a String (usually the URL of a piece of data), and a Bundle of any additional values it would like. All of this information appears back on the parent's Activity.onActivityResult(), along with the integer identifier it originally supplied.

If a child activity fails for any reason (such as crashing), the parent activity will receive a result with the code RESULT_CANCELED.

Here's a sample of how to start a new activity and handle the result:

 public class MyActivity extends Activity {
     ...

     static final int PICK_CONTACT_REQUEST = 0;

     public boolean onKeyDown(int keyCode, KeyEvent event) {
         if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
             // When the user center presses, let them pick a contact.
             startSubActivity(
                 new Intent(Intent.PICK_ACTION,
                 Uri.parse("content://contacts")),
                 PICK_CONTACT_REQUEST);
            return true;
         }
         return false;
     }

     protected void onActivityResult(int requestCode, int resultCode,
             String data, Bundle extras) {
         if (requestCode == PICK_CONTACT_REQUEST) {
             if (resultCode == RESULT_OK) {
                 // A contact was picked.  Here we will just display it
                 // to the user.
                 startActivity(new Intent(Intent.VIEW_ACTION, 
                     Uri.parse(data)));
             }
         }
     }
 }
 

onKeyDown() listens for a key press and starts the new activity. onActivityResult() is called when the new activity finishes.

Saving Persistent State

There are generally two kinds of persistent state than an activity will deal with: shared document-like data (typically stored in a SQLite database using a content provider) and internal state such as user preferences.

For content provider data, we suggest that activities use an "edit in place" user model. That is, any edits a user makes are effectively made immediately without requiring an additional confirmation step. Supporting this model is generally a simple matter of following two rules:

• When creating a new document, the backing database entry or file for it is created immediately. For example, if the user chooses to write a new e-mail, a new entry for that e-mail is created as soon as they start entering data, so that if they go to any other activity after that point this e-mail will now appear in the list of drafts.

• When an activity's onPause() method is called, it should commit to the backing content provider or file any changes the user has made. This ensures that those changes will be seen by any other activity that is about to run. You will probably want to commit your data even more aggressively at key times during your activity's lifecycle: for example before starting a new activity, before finishing your own activity, when the user switches between input fields, etc.

This model is designed to prevent data loss when a user is navigating between activities, and allows the system to safely kill an activity (because system resources are needed somewhere else) at any time after it has been paused. Note this implies that the user pressing BACK from your activity does not mean "cancel" -- it means to leave the activity with its current contents saved away. Cancelling edits in an activity must be provided through some other mechanism, such as an explicit "revert" or "undo" option.

See the content package for more information about content providers. These are a key aspect of how different activities invoke and propagate data between themselves.

The Activity class also provides an API for managing internal persistent state associated with an activity. This can be used, for example, to remember the user's preferred initial display in a calendar (day view or week view) or the user's default home page in a web browser.

Activity persistent state is managed with the method getPreferences(int), allowing you to retrieve and modify a set of name/value pairs associated with the activity. To use preferences that are shared across multiple application components (activities, receivers, services, providers), you can use the underlying Context.getSharedPreferences() method to retrieve a preferences object stored under a specific name. (Note that it is not possible to share settings data across application packages -- for that you will need a content provider.)

Here is an excerpt from a calendar activity that stores the user's preferred view mode in its persistent settings:

 public class CalendarActivity extends Activity {
     ...

     static final int DAY_VIEW_MODE = 0;
     static final int WEEK_VIEW_MODE = 1;

     private SharedPreferences mPrefs;
     private int mCurViewMode;

     protected void onCreate(Bundle icicle) {
         super.onCreate(icicle);

         SharedPreferences mPrefs = getPreferences(MODE_PRIVATE);
         mCurViewMode = mPrefs.getInt("view_mode", DAY_VIEW_MODE);
     }

     protected void onPause() {
         super.onPause();
 
         SharedPreferences.Editor ed = mPrefs.edit();
         ed.putInt("view_mode", mCurViewMode);
         ed.commit();
     }
 }
 

Permissions

The ability to start a particular Activity can be enforced when it is declared in its manifest's <activity> tag. By doing so, other applications will need to declare a corresponding <uses-permission> element in their own manifest to be able to start that activity.

See the Security Model document for more information on permissions and security in general.

Process Lifecycle

The Android system attempts to keep application process around for as long as possible, but eventually will need to remove old processes when memory runs low. As described in Activity Lifecycle, the decision about which process to remove is intimately tied to the state of the user's interaction with it. In general, there are four states a process can be in based on the activities running in it, listed here in order of importance. The system will kill less important processes (the last ones) before it resorts to killing more important processes (the first ones).

1. The foreground activity (the activity at the top of the screen that the user is currently interacting with) is considered the most important. Its process will only be killed as a last resort, if it uses more memory than is available on the device. Generally at this point the device has reached a memory paging state, so this is required in order to keep the user interface responsive.

2. A visible activity (an activity that is visible to the user but not in the foreground, such as one sitting behind a foreground dialog) is considered extremely important and will not be killed unless that is required to keep the foreground activity running.

3. A background activity (an activity that is not visible to the user and has been paused) is no longer critical, so the system may safely kill its process to reclaim memory for other foreground or visible processes. If its process needs to be killed, when the user navigates back to the activity (making it visible on the screen again), its onCreate(Bundle) method will be called with the icicle it had previously supplied in onFreeze(Bundle) so that it can restart itself in the same state as the user last left it.

4. An empty process is one hosting no activities or other application components (such as Service or IntentReceiver classes). These are killed very quickly by the system as memory becomes low. For this reason, any background operation you do outside of an activity must be executed in the context of an activity IntentReceiver or Service to ensure that the system knows it needs to keep your process around.

Sometimes an Activity may need to do a long-running operation that exists independently of the activity lifecycle itself. An example may be a camera application that allows you to upload a picture to a web site. The upload may take a long time, and the application should allow the user to leave the application while it is executing. To accomplish this, your Activity should start a Service in which the upload takes place. This allows the system to properly prioritize your process (considering it to be more important than other non-visible applications) for the duration of the upload, independent of whether the original activity is paused, stopped, or finished.

Known Direct Subclasses

Known Indirect Subclasses

Constants

			Value
int	DIALER_DEFAULT_KEYS	Use with setDefaultKeyMode(int) to launch the dialer during default key handling.	1	0x00000001
int	DISABLE_DEFAULT_KEYS	Use with setDefaultKeyMode(int) to turn off default handling of keys.	0	0x00000000
int[]	FOCUSED_STATE_SET
int	RESULT_CANCELED	Standard activity result: operation canceled.	0	0x00000000
int	RESULT_FIRST_USER	Start of user-defined activity results.	1	0x00000001
int	RESULT_OK	Standard activity result: operation succeeded.	-1	0xffffffff
int	SEARCH_DEFAULT_KEYS	Use with setDefaultKeyMode(int) to specify that unhandled keystrokes will start a search.	3	0x00000003
int	SHORTCUT_DEFAULT_KEYS	Use with setDefaultKeyMode(int) to execute a menu shortcut in default key handling.	2	0x00000002

Constants inherited from class android.content.Context

Public Constructors

Activity()

Public Methods

				void	addContentView(View view, LayoutParams params)
					Add an additional content view to the activity.
				void	closeOptionsMenu()
					Closes the options menu.
				ActivityPendingResult	createActivityPendingResult(int requestCode, boolean multiple)
					Create a new ActivityPendingResult object, which you can hand to others for them to use to send result data back to your onActivityResult(int, int, String, Bundle) callback.
				boolean	dispatchKeyEvent(KeyEvent event)
					Called to process key events.
				boolean	dispatchTouchEvent(MotionEvent ev)
					Called to process touch screen events.
				boolean	dispatchTrackballEvent(MotionEvent ev)
					Called to process trackball events.
				View	findViewById(int id)
					Finds a view that was identified by the id attribute from the XML that was processed in onCreate(Bundle).
				void	finish()
					Call this when your activity is done and should be closed.
				void	finishSubActivity(int requestCode)
					Force finish another activity that you had previously started with startSubActivity(Intent, int).
				void	finishSubActivityFromChild(Activity child, int requestCode)
					This is called when a child activity of this one calls its finishSubActivity().
		final		Application	getApplication()
					Return the application that owns this activity.
				ComponentName	getCallingActivity()
					Return the name of the activity that invoked this activity.
				String	getCallingPackage()
					Return the name of the package that invoked this activity.
				ComponentName	getComponentName()
					Returns complete component name of this activity.
				View	getCurrentFocus()
					Calls getCurrentFocus() on the Window of this Activity to return the currently focused view.
			static	long	getInstanceCount()
				Intent	getIntent()
					Return the intent that started this activity.
				String	getLocalClassName()
					Returns class name for this activity with the package prefix removed.
		final		Activity	getParent()
					Return the parent activity if this view is embedded.
				SharedPreferences	getPreferences(int mode)
					Retrieve a SharedPreferences object for accessing preferences that are private to this activity.
				Object	getSystemService(String name)
					Return the handle to a system-level service by name.
				int	getTaskId()
					Return the identifier of the task this activity is in.
		final		CharSequence	getTitle()
		final		int	getTitleColor()
				ViewInflate	getViewInflate()
					Convenience for calling getViewInflate().
				Window	getWindow()
					Retrieve the current Window for the activity.
				WindowManager	getWindowManager()
					Retrieve the window manager for showing custom windows.
		final		boolean	isEmbedded()
					Is this activity embedded inside of another activity?
				boolean	isFinishing()
					Check to see whether this activity is in the process of finishing, either because you called finish() on it or someone else has requested that it finished.
				boolean	isTaskRoot()
					Return whether this activity is the root of a task.
				void	managedCommitUpdates(Cursor c)
					Wrapper around commitUpdates() that takes care of noting that the Cursor needs to be requeried.
		final		Cursor	managedQuery(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)
					Wrapper around query(android.net.Uri, String[], String, String[], String) that gives the resulting Cursor to call startManagingCursor(Cursor) so that the activity will manage its lifecycle for you.
				boolean	moveTaskBackwards(boolean nonRoot)
					Move the task containing this activity backwards one level in the activity stack.
				boolean	moveTaskToBack(boolean nonRoot)
					Move the task containing this activity to the back of the activity stack.
				void	onContentChanged()
					This hook is called whenever the content view of the screen changes (due to a call to setContentView().
				boolean	onContextItemSelected(Item item)
					This hook is called whenever an item in a context menu is selected.
				void	onContextMenuClosed(Menu menu)
					This hook is called whenever the context menu is being closed (either by the user canceling the menu with the back/menu button, or when an item is selected).
				CharSequence	onCreateDescription()
					Generate a new description for this activity.
				boolean	onCreateOptionsMenu(Menu menu)
					Initialize the contents of the Activity's standard options menu.
				boolean	onCreatePanelMenu(int featureId, Menu menu)
					Default implementation of onCreatePanelMenu(int, Menu) for activities.
				View	onCreatePanelView(int featureId)
					Default implementation of onCreatePanelView(int) for activities.
				boolean	onCreateThumbnail(Bitmap outBitmap, Canvas canvas)
					Generate a new thumbnail for this activity.
				boolean	onKeyDown(int keyCode, KeyEvent event)
					Called when a key was pressed down and not handled by any of the views inside of the activity.
				boolean	onKeyMultiple(int keyCode, int repeatCount, KeyEvent event)
					Default implementation of KeyEvent.Callback.onKeyMultiple(): always returns false (doesn't handle the event).
				boolean	onKeyUp(int keyCode, KeyEvent event)
					Called when a key was released and not handled by any of the views inside of the activity.
				boolean	onMenuItemSelected(int featureId, Item item)
					Default implementation of onMenuItemSelected(int, Menu.Item) for activities.
				boolean	onOptionsItemSelected(Item item)
					This hook is called whenever an item in your options menu is selected.
				void	onOptionsMenuClosed(Menu menu)
					This hook is called whenever the options menu is being closed (either by the user canceling the menu with the back/menu button, or when an item is selected).
				void	onPanelClosed(int featureId, Menu menu)
					Default implementation of onPanelClosed(int, Menu) for activities.
				boolean	onPrepareOptionsMenu(Menu menu)
					Prepare the Screen's standard options menu to be displayed.
				boolean	onPreparePanel(int featureId, View view, Menu menu)
					Default implementation of onPreparePanel(int, View, Menu) for activities.
				boolean	onSearchRequested()
					This hook is called when the user signals the desire to start a search.
				boolean	onTouchEvent(MotionEvent event)
					Called when a touch screen event was not handled by any of the views under it.
				boolean	onTrackballEvent(MotionEvent event)
					Called when the trackball was moved and not handled by any of the views inside of the activity.
				void	onWindowAttributesChanged(LayoutParams params)
					This is called whenever the current window attributes change.
				void	onWindowFocusChanged(boolean hasFocus)
					This hook is called whenever the window focus changes.
				void	openOptionsMenu()
					Opens the options menu.
		final		boolean	requestWindowFeature(int featureId)
					Enable extended window features.
		final		void	runOnUIThread(Runnable action)
					Runs the specified action on the UI thread.
				void	setContentView(int layoutResID)
					Set the activity content from a layout resource.
				void	setContentView(View view, LayoutParams params)
					Set the activity content to an explicit view.
				void	setContentView(View view)
					Set the activity content to an explicit view.
		final		void	setDefaultKeyMode(int mode)
					Select the default key handling for this activity.
		final		void	setFeatureDrawable(int featureId, Drawable drawable)
					Convenience for calling setFeatureDrawable(int, Drawable).
		final		void	setFeatureDrawableAlpha(int featureId, int alpha)
					Convenience for calling setFeatureDrawableAlpha(int, int).
		final		void	setFeatureDrawableResource(int featureId, int resId)
					Convenience for calling setFeatureDrawableResource(int, int).
		final		void	setFeatureDrawableUri(int featureId, Uri uri)
					Convenience for calling setFeatureDrawableUri(int, Uri).
				void	setIntent(Intent newIntent)
					Change the intent returned by getIntent().
				void	setPersistent(boolean isPersistent)
					Control whether this activity is required to be persistent.
		final		void	setProgress(int progress)
					Sets the progress for the progress bars in the title.
		final		void	setProgressBarIndeterminate(boolean indeterminate)
					Sets whether the horizontal progress bar in the title should be indeterminate (the circular is always indeterminate).
		final		void	setProgressBarVisibility(boolean visible)
					Sets the visibility of the progress bars in the title.
		final		void	setResult(int resultCode, String data, Bundle extras)
					Call this to set the result that your activity will return to its caller.
		final		void	setResult(int resultCode, String data)
					Call this to set the result that your activity will return to its caller.
		final		void	setResult(int resultCode)
					Call this to set the result that your activity will return to its caller.
		final		void	setSecondaryProgress(int secondaryProgress)
					Sets the secondary progress for the progress bar in the title.
				void	setTitle(int titleId)
					Change the title associated with this activity.
				void	setTitle(CharSequence title)
					Change the title associated with this activity.
				void	setTitleColor(int textColor)
				void	startActivity(Intent intent)
					Launch a new activity.
				void	startActivityFromChild(Activity child, Intent intent, int requestCode)
					This is called when a child activity of this one calls its startActivity(Intent) or startSubActivity(Intent, int) method.
				void	startManagingCursor(Cursor c)
					This method allows the activity to take care of managing the given Cursor's lifecycle for you based on the activity's lifecycle.
				void	startSearch(String initialQuery, Bundle appSearchData)
					This hook is called to launch the search UI.
				void	startSubActivity(Intent intent, int requestCode)
					Launch a sub-activity.
				boolean	startSubActivityIfNeeded(Intent intent, int requestCode)
					A special variation to launch an activity only if a new activity instance is needed to handle the given Intent.
				void	stopManagingCursor(Cursor c)
					Given a Cursor that was previously given to startManagingCursor(Cursor), stop the activity's management of that cursor.
				void	takeKeyEvents(boolean get)
					Request that key events come to this activity.

Protected Methods

				void	applyThemeResource(Theme theme, int resid, boolean first)
					Called by setTheme(int) and getTheme() to apply a theme resource to the current Theme object.
				void	finalize()
					Called by the virtual machine when there are no longer any (non-weak) references to the receiver.
				boolean	isFullscreenOpaque()
					Returns whether this activity's UI is full-screen and opaque.
				void	onActivityResult(int requestCode, int resultCode, String data, Bundle extras)
					Called when an activity you launched exits, giving you the requestCode you started it with, the resultCode it returned, and any additional data from it.
				void	onChildTitleChanged(Activity childActivity, CharSequence title)
				void	onCompleteThaw(Bundle state)
					This method is called after onStart() when the activity is being re-initialized from a previously saved state, given here in state.
				void	onConfigurationChanged(Configuration newConfig)
					Called by the system when the device configuration changes while your activity is running.
				void	onCreate(Bundle icicle)
					Called when the activity is starting.
				void	onDestroy()
					Perform any final cleanup before an activity is destroyed.
				void	onFreeze(Bundle outState)
					Called to retrieve the current dynamic user-interface state of the activity.
				void	onNewIntent(Intent intent)
					This is called for activities that set launchMode to "singleTop" in their package, or if a client used the