android.view.SurfaceHolder |
Abstract interface to someone holding a display surface. Allows you to
control the surface size and format, edit the pixels in the surface, and
monitor changes to the surface. This interface is typically available
through the SurfaceView
class.
When using this interface from a thread other than the one running
its SurfaceView
, you will want to carefully read the
methods
lockCanvas()
and Callback.surfaceCreated()
.
Nested Classes | |||||||||||
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SurfaceHolder.BadSurfaceTypeException | Exception that is thrown from lockCanvas() when called on a Surface
whose type is SURFACE_TYPE_PUSH_BUFFERS. |
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SurfaceHolder.Callback | A client may implement this interface to receive information about changes to the surface. | ||||||||||
SurfaceHolder.Callback2 | Additional callbacks that can be received for SurfaceHolder.Callback . |
Constants | |||||||||||
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int | SURFACE_TYPE_GPU | This constant was deprecated in API level 5. this is ignored, this value is set automatically when needed. | |||||||||
int | SURFACE_TYPE_HARDWARE | This constant was deprecated in API level 5. this is ignored, this value is set automatically when needed. | |||||||||
int | SURFACE_TYPE_NORMAL | This constant was deprecated in API level 11. this is ignored, this value is set automatically when needed. | |||||||||
int | SURFACE_TYPE_PUSH_BUFFERS | This constant was deprecated in API level 11. this is ignored, this value is set automatically when needed. |
Public Methods | |||||||||||
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Add a Callback interface for this holder.
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Direct access to the surface object.
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Retrieve the current size of the surface.
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Use this method to find out if the surface is in the process of being
created from Callback methods.
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Just like
lockCanvas() but allows specification of a dirty rectangle. | |||||||||||
Start editing the pixels in the surface.
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Removes a previously added Callback interface from this holder.
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Make the surface a fixed size.
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Set the desired PixelFormat of the surface.
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Enable or disable option to keep the screen turned on while this
surface is displayed.
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Allow the surface to resized based on layout of its container (this is
the default).
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This method was deprecated
in API level 11.
this is ignored, this value is set automatically when needed.
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Finish editing pixels in the surface.
|
This constant was deprecated
in API level 5.
this is ignored, this value is set automatically when needed.
This constant was deprecated
in API level 5.
this is ignored, this value is set automatically when needed.
This constant was deprecated
in API level 11.
this is ignored, this value is set automatically when needed.
This constant was deprecated
in API level 11.
this is ignored, this value is set automatically when needed.
Add a Callback interface for this holder. There can several Callback interfaces associated with a holder.
callback | The new Callback interface. |
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Direct access to the surface object. The Surface may not always be
available -- for example when using a SurfaceView
the holder's
Surface is not created until the view has been attached to the window
manager and performed a layout in order to determine the dimensions
and screen position of the Surface. You will thus usually need
to implement Callback.surfaceCreated
to find out when the Surface is available for use.
Note that if you directly access the Surface from another thread,
it is critical that you correctly implement
Callback.surfaceCreated
and
Callback.surfaceDestroyed
to ensure
that thread only accesses the Surface while it is valid, and that the
Surface does not get destroyed while the thread is using it.
This method is intended to be used by frameworks which often need direct access to the Surface object (usually to pass it to native code).
Retrieve the current size of the surface. Note: do not modify the
returned Rect. This is only safe to call from the thread of
SurfaceView
's window, or while inside of
lockCanvas()
.
Use this method to find out if the surface is in the process of being
created from Callback methods. This is intended to be used with
surfaceChanged(SurfaceHolder, int, int, int)
.
Just like lockCanvas()
but allows specification of a dirty rectangle.
Every
pixel within that rectangle must be written; however pixels outside
the dirty rectangle will be preserved by the next call to lockCanvas().
dirty | Area of the Surface that will be modified. |
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Start editing the pixels in the surface. The returned Canvas can be used
to draw into the surface's bitmap. A null is returned if the surface has
not been created or otherwise cannot be edited. You will usually need
to implement Callback.surfaceCreated
to find out when the Surface is available for use.
The content of the Surface is never preserved between unlockCanvas() and lockCanvas(), for this reason, every pixel within the Surface area must be written. The only exception to this rule is when a dirty rectangle is specified, in which case, non-dirty pixels will be preserved.
If you call this repeatedly when the Surface is not ready (before
Callback.surfaceCreated
or after
Callback.surfaceDestroyed
), your calls
will be throttled to a slow rate in order to avoid consuming CPU.
If null is not returned, this function internally holds a lock until
the corresponding unlockCanvasAndPost(Canvas)
call, preventing
SurfaceView
from creating, destroying, or modifying the surface
while it is being drawn. This can be more convenient than accessing
the Surface directly, as you do not need to do special synchronization
with a drawing thread in Callback.surfaceDestroyed
.
Removes a previously added Callback interface from this holder.
callback | The Callback interface to remove. |
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Make the surface a fixed size. It will never change from this size.
When working with a SurfaceView
, this must be called from the
same thread running the SurfaceView's window.
width | The surface's width. |
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height | The surface's height. |
Set the desired PixelFormat of the surface. The default is OPAQUE.
When working with a SurfaceView
, this must be called from the
same thread running the SurfaceView's window.
format | A constant from PixelFormat. |
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Enable or disable option to keep the screen turned on while this surface is displayed. The default is false, allowing it to turn off. This is safe to call from any thread.
screenOn | Set to true to force the screen to stay on, false to allow it to turn off. |
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Allow the surface to resized based on layout of its container (this is
the default). When this is enabled, you should monitor
surfaceChanged(SurfaceHolder, int, int, int)
for changes to the size of the surface.
When working with a SurfaceView
, this must be called from the
same thread running the SurfaceView's window.
This method was deprecated
in API level 11.
this is ignored, this value is set automatically when needed.
Sets the surface's type.
Finish editing pixels in the surface. After this call, the surface's current pixels will be shown on the screen, but its content is lost, in particular there is no guarantee that the content of the Surface will remain unchanged when lockCanvas() is called again.
canvas | The Canvas previously returned by lockCanvas(). |
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