android - 扩展 Gallery 的 CoverFlow(已弃用，在 >4.0 设备中无法正常工作)

Question

我正在使用此类在我的应用中实现 CoverFlow:

public class CoverFlow extends Gallery {

/**
 * Graphics Camera used for transforming the matrix of ImageViews
 */
private Camera mCamera = new Camera();

/**
 * The maximum angle the Child ImageView will be rotated by
 */    
private int mMaxRotationAngle = 60;

/**
 * The maximum zoom on the centre Child
 */
private int mMaxZoom = -175;

/**
 * The Centre of the Coverflow 
 */   
private int mCoveflowCenter;



public CoverFlow(Context context) {
  super(context);
  this.setStaticTransformationsEnabled(true);
 }

 public CoverFlow(Context context, AttributeSet attrs) {
  super(context, attrs);
        this.setStaticTransformationsEnabled(true);
 }

  public CoverFlow(Context context, AttributeSet attrs, int defStyle) {
   super(context, attrs, defStyle);
   this.setStaticTransformationsEnabled(true);   
  }

    /**
     * Get the max rotational angle of the image
  * @return the mMaxRotationAngle
  */
 public int getMaxRotationAngle() {
  return mMaxRotationAngle;
 }

 /**
  * Set the max rotational angle of each image
  * @param maxRotationAngle the mMaxRotationAngle to set
  */
 public void setMaxRotationAngle(int maxRotationAngle) {
  mMaxRotationAngle = maxRotationAngle;
 }

 /**
  * Get the Max zoom of the centre image
  * @return the mMaxZoom
  */
 public int getMaxZoom() {
  return mMaxZoom;
 }

 /**
  * Set the max zoom of the centre image
  * @param maxZoom the mMaxZoom to set
  */
 public void setMaxZoom(int maxZoom) {
  mMaxZoom = maxZoom;
 }

 /**
     * Get the Centre of the Coverflow
     * @return The centre of this Coverflow.
     */
    private int getCenterOfCoverflow() {
        return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2 + getPaddingLeft();
    }

    /**
     * Get the Centre of the View
     * @return The centre of the given view.
     */
    private static int getCenterOfView(View view) {
        return view.getLeft() + view.getWidth() / 2;
    }  
    /**
  * {@inheritDoc}
  *
  * @see #setStaticTransformationsEnabled(boolean) 
  */ 
    protected boolean getChildStaticTransformation(View child, Transformation t) {

  final int childCenter = getCenterOfView(child);
  final int childWidth = child.getWidth() ;
  int rotationAngle = 0;

  t.clear();
  t.setTransformationType(Transformation.TYPE_MATRIX);

        if (childCenter == mCoveflowCenter) {
            //PARCHE!!! 4.1
            if (Build.VERSION.SDK_INT > Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1){

            } else {
                transformImageBitmap((ImageView) child, t, 0);
            }

        } else {  

            rotationAngle = (int) (((float) (mCoveflowCenter - childCenter)/ childWidth) *  mMaxRotationAngle);
            if (Math.abs(rotationAngle) > mMaxRotationAngle) {
             rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle : mMaxRotationAngle;   
            }
            //PARCHE!!! 4.1
            if (Build.VERSION.SDK_INT > Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1){
                //no apliquem transformacio.
            } else {
                transformImageBitmap((ImageView) child, t, rotationAngle); 
            }    
        }    

  return true;
 }

 /**
  * This is called during layout when the size of this view has changed. If
  * you were just added to the view hierarchy, you're called with the old
  * values of 0.
  *
  * @param w Current width of this view.
  * @param h Current height of this view.
  * @param oldw Old width of this view.
  * @param oldh Old height of this view.
     */
     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
      mCoveflowCenter = getCenterOfCoverflow();
      super.onSizeChanged(w, h, oldw, oldh);
     }

     /**
      * Transform the Image Bitmap by the Angle passed 
      * 
      * @param imageView ImageView the ImageView whose bitmap we want to rotate
      * @param t transformation 
      * @param rotationAngle the Angle by which to rotate the Bitmap
      */
     private void transformImageBitmap(ImageView child, Transformation t, int rotationAngle) {            
      mCamera.save();
      final Matrix imageMatrix = t.getMatrix();;
      final int imageHeight = child.getLayoutParams().height;
      final int imageWidth = child.getLayoutParams().width;
      final int rotation = Math.abs(rotationAngle);

      mCamera.translate(0.0f, 0.0f, 100.0f);

      //As the angle of the view gets less, zoom in     
      if ( rotation < mMaxRotationAngle ) {
       float zoomAmount = (float) (mMaxZoom +  (rotation * 2.9));
       mCamera.translate(0.0f, 0.0f, zoomAmount);          
      } 

      mCamera.rotateY(rotationAngle);
      mCamera.getMatrix(imageMatrix);               
      imageMatrix.preTranslate(-(imageWidth/2), -(imageHeight/2)); 
      imageMatrix.postTranslate((imageWidth/2), (imageHeight/2));
      mCamera.restore();
 }
}

但这段代码在 4.0 设备(如 4.1 或 4.2)之后不再运行良好。

我做了一些调试，所以我修改了这部分:

//As the angle of the view gets less, zoom in     
  if ( rotation < mMaxRotationAngle ) {
      Log.d("sergi",""+rotation);
   float zoomAmount = (float) (mMaxZoom +  (rotation * 2.9));
   mCamera.translate(0.0f, 0.0f, zoomAmount);          
  } 

这在 4.0.4 设备上返回了这个，同时从右向左滑动一张图像:

03-20 11:11:43.145: D/debugging(15987): 1
03-20 11:11:43.160: D/debugging(15987): 54
03-20 11:11:43.160: D/debugging(15987): 59
03-20 11:11:43.160: D/debugging(15987): 2
03-20 11:11:43.176: D/debugging(15987): 53
03-20 11:11:43.176: D/debugging(15987): 3
03-20 11:11:43.192: D/debugging(15987): 52
03-20 11:11:43.192: D/debugging(15987): 4
03-20 11:11:43.207: D/debugging(15987): 51
03-20 11:11:43.207: D/debugging(15987): 5
03-20 11:11:43.223: D/debugging(15987): 50
03-20 11:11:43.223: D/debugging(15987): 6
03-20 11:11:43.239: D/debugging(15987): 48
03-20 11:11:43.239: D/debugging(15987): 8
03-20 11:11:43.254: D/debugging(15987): 47
03-20 11:11:43.254: D/debugging(15987): 9

在 4.1 设备上它返回:

03-20 11:11:49.239: D/debugging(15987): 35
03-20 11:11:49.254: D/debugging(15987): 35

如您所见，基本上发生的情况是，相同的方法在两个不同的 API 之间的使用方式不同。

如您所见，CoverFlow 扩展了已弃用但未删除的 Gallery，所以我不明白有什么区别。如果我们能找到解决方法，我将不胜感激。

谢谢。

Answer 1

也许这会有所帮助:

protected boolean getChildStaticTransformation(View child, Transformation t)
{
              .....

    if (Build.VERSION.SDK_INT >= 16) child.invalidate();

    return true;
}

这将使 child 无效并使其应用动画。