我正在使用此类在我的应用程序中实现 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();
}
}
但是这段代码，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);
}
这会在 4.0.4 设备上返回，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，基本上正在发生的事情是，相同的方法在两个不同的 api 之间没有以相同的方式使用。
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。