io.flutter.embedding.android.FlutterImageView Class Reference

Inheritance diagram for io.flutter.embedding.android.FlutterImageView:

Classes
enum	SurfaceKind

Public Member Functions
ImageReader	getImageReader ()
	FlutterImageView (@NonNull Context context, int width, int height, SurfaceKind kind)
	FlutterImageView (@NonNull Context context)
	FlutterImageView (@NonNull Context context, @NonNull AttributeSet attrs)
Surface	getSurface ()
FlutterRenderer	getAttachedRenderer ()
void	attachToRenderer (@NonNull FlutterRenderer flutterRenderer)
void	detachFromRenderer ()
void	pause ()
void	resume ()
boolean	acquireLatestImage ()
void	resizeIfNeeded (int width, int height)
void	closeImageReader ()
FlutterRenderer	getAttachedRenderer ()
void	attachToRenderer (@NonNull FlutterRenderer renderer)
void	detachFromRenderer ()
void	pause ()
void	resume ()

Protected Member Functions
void	onDraw (Canvas canvas)
void	onSizeChanged (int width, int height, int oldWidth, int oldHeight)

Package Functions
	FlutterImageView ( @NonNull Context context, @NonNull ImageReader imageReader, SurfaceKind kind)

Detailed Description

Paints a Flutter UI provided by an android.media.ImageReader onto a android.graphics.Canvas.

A FlutterImageView is intended for situations where a developer needs to render a Flutter UI, but also needs to render an interactive io.flutter.plugin.platform.PlatformView.

This View takes an android.media.ImageReader that provides the Flutter UI in an android.media.Image and renders it to the android.graphics.Canvas in
onDraw.

Definition at line 44 of file FlutterImageView.java.

Constructor & Destructor Documentation

FlutterImageView() [1/4]

io.flutter.embedding.android.FlutterImageView.FlutterImageView ( @NonNull Context  context, int  width, int  height, SurfaceKind  kind  )

inline

Constructs a FlutterImageView with an android.media.ImageReader that provides the Flutter UI.

Definition at line 74 of file FlutterImageView.java.

                                                                                             {
    this(context, createImageReader(width, height), kind);
  }

FlutterImageView() [2/4]

io.flutter.embedding.android.FlutterImageView.FlutterImageView ( @NonNull Context  context )

inline

Definition at line 78 of file FlutterImageView.java.

                                                    {
    this(context, 1, 1, SurfaceKind.background);
  }

FlutterImageView() [3/4]

io.flutter.embedding.android.FlutterImageView.FlutterImageView ( @NonNull Context  context, @NonNull AttributeSet  attrs  )

inline

Definition at line 82 of file FlutterImageView.java.

                                                                                 {
    this(context, 1, 1, SurfaceKind.background);
  }

FlutterImageView() [4/4]

io.flutter.embedding.android.FlutterImageView.FlutterImageView ( @NonNull Context  context, @NonNull ImageReader  imageReader, SurfaceKind  kind  )

inlinepackage

Definition at line 87 of file FlutterImageView.java.

                                                                                    {
    super(context, null);
    this.imageReader = imageReader;
    this.kind = kind;
    init();
  }

Member Function Documentation

acquireLatestImage()

boolean io.flutter.embedding.android.FlutterImageView.acquireLatestImage ( )

inline

Acquires the next image to be drawn to the android.graphics.Canvas. Returns true if there's an image available in the queue.

Definition at line 190 of file FlutterImageView.java.

                                      {
    if (!isAttachedToFlutterRenderer) {
      return false;
    }
    // 1. `acquireLatestImage()` may return null if no new image is available.
    // 2. There's no guarantee that `onDraw()` is called after `invalidate()`.
    // For example, the device may not produce new frames if it's in sleep mode
    // or some special Android devices so the calls to `invalidate()` queued up
    // until the device produces a new frame.
    // 3. While the engine will also stop producing frames, there is a race condition.
    final Image newImage = imageReader.acquireLatestImage();
    if (newImage != null) {
      // Only close current image after acquiring valid new image
      closeCurrentImage();
      currentImage = newImage;
      invalidate();
    }
    return newImage != null;
  }

attachToRenderer()

void io.flutter.embedding.android.FlutterImageView.attachToRenderer ( @NonNull FlutterRenderer  flutterRenderer )

inline

Invoked by the owner of this FlutterImageView when it wants to begin rendering a Flutter UI to this FlutterImageView.

Implements io.flutter.embedding.engine.renderer.RenderSurface.

Definition at line 142 of file FlutterImageView.java.

                                                                         {
    switch (kind) {
      case background:
        flutterRenderer.swapSurface(imageReader.getSurface());
        break;
      case overlay:
        // Do nothing since the attachment is done by the handler of
        // `FlutterJNI#createOverlaySurface()` in the native side.
        break;
    }
    setAlpha(1.0f);
    this.flutterRenderer = flutterRenderer;
    isAttachedToFlutterRenderer = true;
  }

closeImageReader()

void io.flutter.embedding.android.FlutterImageView.closeImageReader ( )

inline

Closes the image reader associated with the current FlutterImageView.

Once the image reader is closed, calling acquireLatestImage will result in an
IllegalStateException.

Definition at line 233 of file FlutterImageView.java.

                                 {
    imageReader.close();
  }

detachFromRenderer()

void io.flutter.embedding.android.FlutterImageView.detachFromRenderer ( )

inline

Invoked by the owner of this FlutterImageView when it no longer wants to render a Flutter UI to this FlutterImageView.

Implements io.flutter.embedding.engine.renderer.RenderSurface.

Definition at line 161 of file FlutterImageView.java.

                                   {
    if (!isAttachedToFlutterRenderer) {
      return;
    }
    setAlpha(0.0f);
    // Drop the latest image as it shouldn't render this image if this view is
    // attached to the renderer again.
    acquireLatestImage();
    // Clear drawings.
    currentBitmap = null;
 
    // Close and clear the current image if any.
    closeCurrentImage();
    invalidate();
    isAttachedToFlutterRenderer = false;
  }

getAttachedRenderer()

FlutterRenderer io.flutter.embedding.android.FlutterImageView.getAttachedRenderer ( )

inline

Returns the FlutterRenderer that is attached to this RenderSurface, or null if no FlutterRenderer is currently attached.

Implements io.flutter.embedding.engine.renderer.RenderSurface.

Definition at line 133 of file FlutterImageView.java.

                                               {
    return flutterRenderer;
  }

getImageReader()

ImageReader io.flutter.embedding.android.FlutterImageView.getImageReader ( )

inline

Definition at line 52 of file FlutterImageView.java.

                                      {
    return imageReader;
  }

getSurface()

Surface io.flutter.embedding.android.FlutterImageView.getSurface ( )

inline

Definition at line 127 of file FlutterImageView.java.

                              {
    return imageReader.getSurface();
  }

onDraw()

void io.flutter.embedding.android.FlutterImageView.onDraw ( Canvas  canvas )

inlineprotected

Definition at line 238 of file FlutterImageView.java.

                                       {
    super.onDraw(canvas);
    if (currentImage != null) {
      updateCurrentBitmap();
    }
    if (currentBitmap != null) {
      canvas.drawBitmap(currentBitmap, 0, 0, null);
    }
  }

onSizeChanged()

void io.flutter.embedding.android.FlutterImageView.onSizeChanged ( int  width, int  height, int  oldWidth, int  oldHeight  )

inlineprotected

Definition at line 286 of file FlutterImageView.java.

                                                                                   {
    if (width == imageReader.getWidth() && height == imageReader.getHeight()) {
      return;
    }
    // `SurfaceKind.overlay` isn't resized. Instead, the `FlutterImageView` instance
    // is destroyed. As a result, an instance with the new size is created by the surface
    // pool in the native side.
    if (kind == SurfaceKind.background && isAttachedToFlutterRenderer) {
      resizeIfNeeded(width, height);
      // Bind native window to the new surface, and create a new onscreen surface
      // with the new size in the native side.
      flutterRenderer.swapSurface(imageReader.getSurface());
    }
  }

pause()

void io.flutter.embedding.android.FlutterImageView.pause ( )

inline

Instructs this RenderSurface to stop forwarding Surface notifications to the FlutterRenderer that was previously connected with attachToRenderer(FlutterRenderer).

Implements io.flutter.embedding.engine.renderer.RenderSurface.

Definition at line 178 of file FlutterImageView.java.

                      {
    // Not supported.
  }

resizeIfNeeded()

void io.flutter.embedding.android.FlutterImageView.resizeIfNeeded ( int  width, int  height  )

inline

Creates a new image reader with the provided size.

Definition at line 211 of file FlutterImageView.java.

                                                    {
    if (flutterRenderer == null) {
      return;
    }
    if (width == imageReader.getWidth() && height == imageReader.getHeight()) {
      return;
    }
 
    // Close resources.
    closeCurrentImage();
    // Close the current image reader, then create a new one with the new size.
    // Image readers cannot be resized once created.
    closeImageReader();
    imageReader = createImageReader(width, height);
  }

resume()

void io.flutter.embedding.android.FlutterImageView.resume ( )

inline

Instructs this RenderSurface to resume forwarding Surface notifications to the FlutterRenderer that was previously connected with attachToRenderer(FlutterRenderer).

Implements io.flutter.embedding.engine.renderer.RenderSurface.

Definition at line 182 of file FlutterImageView.java.

                       {
    // Not supported.
  }

---

The documentation for this class was generated from the following file:

• shell/platform/android/io/flutter/embedding/android/FlutterImageView.java