Android使用Rotate3dAnimation实现3D旋转动画效果的实例代码

　　public class Rotate3dAnimation extends Animation {

　　private final float mFromDegrees;

　　private final float mToDegrees;

　　private final float mCenterX;

　　private final float mCenterY;

　　private final float mDepthZ;

　　private final boolean mReverse;

　　private Camera mCamera;

　　/**

　　* Creates a new 3D rotation on the Y axis. The rotation is defined by its

　　* start angle and its end angle. Both angles are in degrees. The rotation

　　* is performed around a center point on the 2D space, definied by a pair

　　* of X and Y coordinates, called centerX and centerY. When the animation

　　* starts, a translation on the Z axis (depth) is performed. The length

　　* of the translation can be specified, as well as whether the translation

　　* should be reversed in time.

　　*

　　* @param fromDegrees the start angle of the 3D rotation

　　* @param toDegrees the end angle of the 3D rotation

　　* @param centerX the X center of the 3D rotation

　　* @param centerY the Y center of the 3D rotation

　　* @param reverse true if the translation should be reversed, false otherwise

　　*/

　　public Rotate3dAnimation(float fromDegrees, float toDegrees,

　　float centerX, float centerY, float depthZ, boolean reverse) {

　　mFromDegrees = fromDegrees;

　　mToDegrees = toDegrees;

　　mCenterX = centerX;

　　mCenterY = centerY;

　　mDepthZ = depthZ;

　　mReverse = reverse;

　　}

　　@Override

　　public void initialize(int width, int height, int parentWidth, int parentHeight) {

　　super.initialize(width, height, parentWidth, parentHeight);

　　mCamera = new Camera();

　　}

　　@Override

　　protected void applyTransformation(float interpolatedTime, Transformation t) {

　　final float fromDegrees = mFromDegrees;

　　float degrees = fromDegrees + ((mToDegrees - fromDegrees) * interpolatedTime);

　　final float centerX = mCenterX;

　　final float centerY = mCenterY;

　　final Camera camera = mCamera;

　　final Matrix matrix = t.getMatrix();

　　//保存一次camera初始状态，用于restore()

　　camera.save();

　　if (mReverse) {

　　camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);

　　} else {

　　camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));

　　}

　　//围绕Y轴旋转degrees度

　　camera.rotateY(degrees);

　　//行camera中取出矩阵，赋值给matrix

　　camera.getMatrix(matrix);

　　//camera恢复到初始状态，继续用于下次的计算

　　camera.restore();

　　matrix.preTranslate(-centerX, -centerY);

　　matrix.postTranslate(centerX, centerY);

　　}

　　}