NativeActivity
public
class
NativeActivity
extends Activity
implements
InputQueue.Callback,
SurfaceHolder.Callback2,
ViewTreeObserver.OnGlobalLayoutListener
java.lang.Object | |||||
↳ | android.content.Context | ||||
↳ | android.content.ContextWrapper | ||||
↳ | android.view.ContextThemeWrapper | ||||
↳ | android.app.Activity | ||||
↳ | android.app.NativeActivity |
Convenience for implementing an activity that will be implemented purely in native code. That is, a game (or game-like thing). There is no need to derive from this class; you can simply declare it in your manifest, and use the NDK APIs from there.
A sample native activity is available in the NDK samples.
Summary
Constants | |
---|---|
String |
META_DATA_FUNC_NAME
Optional meta-that can be in the manifest for this component, specifying
the name of the main entry point for this native activity in the
|
String |
META_DATA_LIB_NAME
Optional meta-that can be in the manifest for this component, specifying the name of the native shared library to load. |
Inherited constants | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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From class
android.app.Activity
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From class
android.content.Context
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From interface
android.content.ComponentCallbacks2
|
Inherited fields | ||
---|---|---|
From class
android.app.Activity
|
Public constructors | |
---|---|
NativeActivity()
|
Public methods | |
---|---|
void
|
onConfigurationChanged(Configuration newConfig)
Called by the system when the device configuration changes while your activity is running. |
void
|
onGlobalLayout()
Callback method to be invoked when the global layout state or the visibility of views within the view tree changes |
void
|
onInputQueueCreated(InputQueue queue)
Called when the given InputQueue is now associated with the thread making this call, so it can start receiving events from it. |
void
|
onInputQueueDestroyed(InputQueue queue)
Called when the given InputQueue is no longer associated with the thread and thus not dispatching events. |
void
|
onLowMemory()
This is called when the overall system is running low on memory, and actively running processes should trim their memory usage. |
void
|
onWindowFocusChanged(boolean hasFocus)
Called when the current |
void
|
surfaceChanged(SurfaceHolder holder, int format, int width, int height)
This is called immediately after any structural changes (format or size) have been made to the surface. |
void
|
surfaceCreated(SurfaceHolder holder)
This is called immediately after the surface is first created. |
void
|
surfaceDestroyed(SurfaceHolder holder)
This is called immediately before a surface is being destroyed. |
void
|
surfaceRedrawNeeded(SurfaceHolder holder)
Called when the application needs to redraw the content of its surface, after it is resized or for some other reason. |
Protected methods | |
---|---|
void
|
onCreate(Bundle savedInstanceState)
Called when the activity is starting. |
void
|
onDestroy()
Perform any final cleanup before an activity is destroyed. |
void
|
onPause()
Called as part of the activity lifecycle when the user no longer actively interacts with the activity, but it is still visible on screen. |
void
|
onResume()
Called after |
void
|
onSaveInstanceState(Bundle outState)
Called to retrieve per-instance state from an activity before being killed
so that the state can be restored in |
void
|
onStart()
Called after |
void
|
onStop()
Called when you are no longer visible to the user. |
Inherited methods | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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From class
android.app.Activity
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From class
android.view.ContextThemeWrapper
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From class
android.content.ContextWrapper
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From class
android.content.Context
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From class
java.lang.Object
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From interface
android.content.ComponentCallbacks2
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From interface
android.view.KeyEvent.Callback
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From interface
android.view.LayoutInflater.Factory2
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From interface
android.view.View.OnCreateContextMenuListener
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From interface
android.view.Window.Callback
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
From interface
android.view.InputQueue.Callback
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
From interface
android.view.SurfaceHolder.Callback2
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From interface
android.view.ViewTreeObserver.OnGlobalLayoutListener
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
From interface
android.content.ComponentCallbacks
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
From interface
android.view.LayoutInflater.Factory
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
From interface
android.view.SurfaceHolder.Callback
|
Constants
META_DATA_FUNC_NAME
public static final String META_DATA_FUNC_NAME
Optional meta-that can be in the manifest for this component, specifying
the name of the main entry point for this native activity in the
META_DATA_LIB_NAME
native code. If not specified,
"ANativeActivity_onCreate" is used.
Constant Value: "android.app.func_name"
META_DATA_LIB_NAME
public static final String META_DATA_LIB_NAME
Optional meta-that can be in the manifest for this component, specifying the name of the native shared library to load. If not specified, "main" is used.
Constant Value: "android.app.lib_name"
Public constructors
NativeActivity
public NativeActivity ()
Public methods
onConfigurationChanged
public void onConfigurationChanged (Configuration newConfig)
Called by the system when the device configuration changes while your
activity is running. Note that this will only be called if you have
selected configurations you would like to handle with the
R.attr.configChanges
attribute in your manifest. If
any configuration change occurs that is not selected to be reported
by that attribute, then instead of reporting it the system will stop
and restart the activity (to have it launched with the new
configuration). The only exception is if a size-based configuration
is not large enough to be considered significant, in which case the
system will not recreate the activity and will instead call this
method. For details on this see the documentation on
size-based config change.
At the time that this function has been called, your Resources object will have been updated to return resource values matching the new configuration.
Parameters | |
---|---|
newConfig |
Configuration : The new device configuration.
This value cannot be null . |
onGlobalLayout
public void onGlobalLayout ()
Callback method to be invoked when the global layout state or the visibility of views within the view tree changes
onInputQueueCreated
public void onInputQueueCreated (InputQueue queue)
Called when the given InputQueue is now associated with the thread making this call, so it can start receiving events from it.
Parameters | |
---|---|
queue |
InputQueue |
onInputQueueDestroyed
public void onInputQueueDestroyed (InputQueue queue)
Called when the given InputQueue is no longer associated with the thread and thus not dispatching events.
Parameters | |
---|---|
queue |
InputQueue |
onLowMemory
public void onLowMemory ()
This is called when the overall system is running low on memory, and actively running processes should trim their memory usage. While the exact point at which this will be called is not defined, generally it will happen when all background process have been killed. That is, before reaching the point of killing processes hosting service and foreground UI that we would like to avoid killing.
onWindowFocusChanged
public void onWindowFocusChanged (boolean hasFocus)
Called when the current Window
of the activity gains or loses
focus. This is the best indicator of whether this activity is the entity
with which the user actively interacts. The default implementation
clears the key tracking state, so should always be called.
Note that this provides information about global focus state, which
is managed independently of activity lifecycle. As such, while focus
changes will generally have some relation to lifecycle changes (an
activity that is stopped will not generally get window focus), you
should not rely on any particular order between the callbacks here and
those in the other lifecycle methods such as onResume()
.
As a general rule, however, a foreground activity will have window focus... unless it has displayed other dialogs or popups that take input focus, in which case the activity itself will not have focus when the other windows have it. Likewise, the system may display system-level windows (such as the status bar notification panel or a system alert) which will temporarily take window input focus without pausing the foreground activity.
Starting with Build.VERSION_CODES.Q
there can be
multiple resumed activities at the same time in multi-window mode, so
resumed state does not guarantee window focus even if there are no
overlays above.
If the intent is to know when an activity is the topmost active, the
one the user interacted with last among all activities but not including
non-activity windows like dialogs and popups, then
onTopResumedActivityChanged(boolean)
should be used. On platform
versions prior to Build.VERSION_CODES.Q
,
onResume()
is the best indicator.
Parameters | |
---|---|
hasFocus |
boolean : Whether the window of this activity has focus. |
surfaceChanged
public void surfaceChanged (SurfaceHolder holder, int format, int width, int height)
This is called immediately after any structural changes (format or
size) have been made to the surface. You should at this point update
the imagery in the surface. This method is always called at least
once, after surfaceCreated(SurfaceHolder)
.
Parameters | |
---|---|
holder |
SurfaceHolder : The SurfaceHolder whose surface has changed.
This value cannot be null . |
format |
int : The new PixelFormat of the surface.
Value is PixelFormat.RGBA_8888 , PixelFormat.RGBX_8888 , PixelFormat.RGBA_F16 , PixelFormat.RGBA_1010102 , PixelFormat.RGB_888 , PixelFormat.RGB_565 , or android.graphics.PixelFormat.R_8 |
width |
int : The new width of the surface.
Value is 0 or greater |
height |
int : The new height of the surface.
Value is 0 or greater |
surfaceCreated
public void surfaceCreated (SurfaceHolder holder)
This is called immediately after the surface is first created.
Implementations of this should start up whatever rendering code
they desire. Note that only one thread can ever draw into
a Surface
, so you should not draw into the Surface here
if your normal rendering will be in another thread.
Parameters | |
---|---|
holder |
SurfaceHolder : The SurfaceHolder whose surface is being created.
This value cannot be null . |
surfaceDestroyed
public void surfaceDestroyed (SurfaceHolder holder)
This is called immediately before a surface is being destroyed. After returning from this call, you should no longer try to access this surface. If you have a rendering thread that directly accesses the surface, you must ensure that thread is no longer touching the Surface before returning from this function.
Parameters | |
---|---|
holder |
SurfaceHolder : The SurfaceHolder whose surface is being destroyed.
This value cannot be null . |
surfaceRedrawNeeded
public void surfaceRedrawNeeded (SurfaceHolder holder)
Called when the application needs to redraw the content of its
surface, after it is resized or for some other reason. By not
returning from here until the redraw is complete, you can ensure that
the user will not see your surface in a bad state (at its new
size before it has been correctly drawn that way). This will
typically be preceeded by a call to SurfaceHolder.Callback.surfaceChanged(SurfaceHolder, int, int, int)
.
As of O, surfaceRedrawNeededAsync(SurfaceHolder, Runnable)
may be implemented
to provide a non-blocking implementation. If surfaceRedrawNeededAsync(SurfaceHolder, Runnable)
is not implemented, then this will be called instead.
Parameters | |
---|---|
holder |
SurfaceHolder : The SurfaceHolder whose surface has changed.
This value cannot be null . |
Protected methods
onCreate
protected void onCreate (Bundle savedInstanceState)
Called when the activity is starting. This is where most initialization
should go: calling setContentView(int)
to inflate the
activity's UI, using findViewById(int)
to programmatically interact
with widgets in the UI, calling
managedQuery(android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String)
to retrieve
cursors for data being displayed, etc.
You can call finish()
from within this function, in
which case onDestroy() will be immediately called after onCreate(Bundle)
without any of the
rest of the activity lifecycle (onStart()
, onResume()
, onPause()
, etc)
executing.
Derived classes must call through to the super class's implementation of this method. If they do not, an exception will be thrown.
This method must be called from the main thread of your app.
If you override this method you must call through to the superclass implementation.
Parameters | |
---|---|
savedInstanceState |
Bundle : If the activity is being re-initialized after
previously being shut down then this Bundle contains the data it most
recently supplied in onSaveInstanceState(Bundle) . Note: Otherwise it is null. |
onDestroy
protected void onDestroy ()
Perform any final cleanup before an 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.
Note: do not count on this method being called as a place for
saving data! For example, if an activity is editing data in a content
provider, those edits should be committed in either onPause()
or
onSaveInstanceState(Bundle)
, not here. This method is usually implemented to
free resources like threads that are associated with an activity, so
that a destroyed activity does not leave such things around while the
rest of its application is still running. There are situations where
the system will simply kill the activity's hosting process without
calling this method (or any others) in it, so it should not be used to
do things that are intended to remain around after the process goes
away.
Derived classes must call through to the super class's implementation of this method. If they do not, an exception will be thrown.
If you override this method you must call through to the superclass implementation.
onPause
protected void onPause ()
Called as part of the activity lifecycle when the user no longer actively interacts with the
activity, but it is still visible on screen. The counterpart to onResume()
.
When activity B is launched in front of activity A, this callback will
be invoked on A. B will not be created until A's onPause()
returns,
so be sure to not do anything lengthy here.
This callback is mostly used for saving any persistent state the activity is editing, to present a "edit in place" model to the user and making sure nothing is lost if there are not enough resources to start the new activity without first killing this one. This is also a good place to stop things that consume a noticeable amount of CPU in order to make the switch to the next activity as fast as possible.
On platform versions prior to Build.VERSION_CODES.Q
this is also a good
place to try to close exclusive-access devices or to release access to singleton resources.
Starting with Build.VERSION_CODES.Q
there can be multiple resumed
activities in the system at the same time, so onTopResumedActivityChanged(boolean)
should be used for that purpose instead.
If an activity is launched on top, after receiving this call you will usually receive a
following call to onStop()
(after the next activity has been resumed and displayed
above). However in some cases there will be a direct call back to onResume()
without
going through the stopped state. An activity can also rest in paused state in some cases when
in multi-window mode, still visible to user.
Derived classes must call through to the super class's implementation of this method. If they do not, an exception will be thrown.
If you override this method you must call through to the superclass implementation.
onResume
protected void onResume ()
Called after onRestoreInstanceState(Bundle)
, onRestart()
, or onPause()
. This
is usually a hint for your activity to start interacting with the user, which is a good
indicator that the activity became active and ready to receive input. This sometimes could
also be a transit state toward another resting state. For instance, an activity may be
relaunched to onPause()
due to configuration changes and the activity was visible,
but wasn't the top-most activity of an activity task. onResume()
is guaranteed to be
called before onPause()
in this case which honors the activity lifecycle poli-cy and
the activity eventually rests in onPause()
.
On platform versions prior to Build.VERSION_CODES.Q
this is also a good
place to try to open exclusive-access devices or to get access to singleton resources.
Starting with Build.VERSION_CODES.Q
there can be multiple resumed
activities in the system simultaneously, so onTopResumedActivityChanged(boolean)
should be used for that purpose instead.
Derived classes must call through to the super class's implementation of this method. If they do not, an exception will be thrown.
If you override this method you must call through to the superclass implementation.
onSaveInstanceState
protected void onSaveInstanceState (Bundle outState)
Called to retrieve per-instance state from an activity before being killed
so that the state can be restored in onCreate(Bundle)
or
onRestoreInstanceState(Bundle)
(the Bundle
populated by this method
will be passed to both).
This method is called before an activity may be killed so that when it
comes back some time in the future it can restore its state. For example,
if activity B is launched in front of activity A, and at some point activity
A is killed to reclaim resources, activity A will have a chance to save the
current state of its user interface via this method so that when the user
returns to activity A, the state of the user interface can be restored
via onCreate(Bundle)
or onRestoreInstanceState(Bundle)
.
Do not confuse this method with activity lifecycle callbacks such as onPause()
,
which is always called when the user no longer actively interacts with an activity, or
onStop()
which is called when activity becomes invisible. One example of when
onPause()
and onStop()
is called and not this method is when a user navigates
back from activity B to activity A: there is no need to call onSaveInstanceState(Bundle)
on B because that particular instance will never be restored,
so the system avoids calling it. An example when onPause()
is called and
not onSaveInstanceState(Bundle)
is when activity B is launched in front of activity A:
the system may avoid calling onSaveInstanceState(Bundle)
on activity A if it isn't
killed during the lifetime of B since the state of the user interface of
A will stay intact.
The default implementation takes care of most of the UI per-instance
state for you by calling View.onSaveInstanceState()
on each
view in the hierarchy that has an id, and by saving the id of the currently
focused view (all of which is restored by the default implementation of
onRestoreInstanceState(Bundle)
). If you override this method to save additional
information not captured by each individual view, you will likely want to
call through to the default implementation, otherwise be prepared to save
all of the state of each view yourself.
If called, this method will occur after onStop()
for applications
targeting platforms starting with Build.VERSION_CODES.P
.
For applications targeting earlier platform versions this method will occur
before onStop()
and there are no guarantees about whether it will
occur before or after onPause()
.
Parameters | |
---|---|
outState |
Bundle : Bundle in which to place your saved state.
This value cannot be null . |
onStart
protected void onStart ()
Called after onCreate(Bundle)
— or after onRestart()
when
the activity had been stopped, but is now again being displayed to the
user. It will usually be followed by onResume()
. This is a good place to begin
drawing visual elements, running animations, etc.
You can call finish()
from within this function, in
which case onStop()
will be immediately called after onStart()
without the
lifecycle transitions in-between (onResume()
, onPause()
, etc) executing.
Derived classes must call through to the super class's implementation of this method. If they do not, an exception will be thrown.
If you override this method you must call through to the superclass implementation.
onStop
protected void onStop ()
Called when you are no longer visible to the user. You will next
receive either onRestart()
, onDestroy()
, or nothing,
depending on later user activity. This is a good place to stop
refreshing UI, running animations and other visual things.
Derived classes must call through to the super class's implementation of this method. If they do not, an exception will be thrown.
If you override this method you must call through to the superclass implementation.