Flip Animation for Android:
最近项目中用到了一个小动画，让物体实现一定的3D旋转效果，现记录如下：
public class FlipAnimation extends Animation {
private Camera mCamera;
private View mFromView;
private View mToView;
private float mCenterX;
private float mCenterY;
private boolean mForward = true;
/**
* Creates a 3D flip animation between two views.
*
* @param fromView First view in the transition.
* @param toView Second view in the transition.
*/
public FlipAnimation(View fromView, View toView) {
mFromView = fromView;
mToView = toView;
setDuration(700);
setFillAfter(false);
setInterpolator(new AccelerateDecelerateInterpolator());
}
public void reverse() {
mForward = false;
View switchView = mToView;
mToView = mFromView;
mFromView = switchView;
}
@Override
public void initialize(int width, int height, int parentWidth, int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
mCenterX = width / 2;
mCenterY = height / 2;
mCamera = new Camera();
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
final double radians = Math.PI * interpolatedTime;
float degrees = (float)(180.0 * radians / Math.PI);
if (interpolatedTime >= 0.5f) {
degrees -= 180.f;
mFromView.setVisibility(View.GONE);
mToView.setVisibility(View.VISIBLE);
}
if (mForward) {
degrees = -degrees;
}
final Matrix matrix = t.getMatrix();
mCamera.save();
mCamera.rotateY(degrees);
mCamera.getMatrix(matrix);
mCamera.restore();
matrix.preTranslate(-mCenterX, -mCenterY);
matrix.postTranslate(mCenterX, mCenterY);
}
}