[Android] 文字翻转动画的实现
package lab.sodino.rotate;import android.graphics.Camera;import android.graphics.Matrix;import android.view.animation.Animation;import android.view.animation.Transformation;/** * @author Sodino E-mail:sodinoopen@hotmail.com * @version Time：2012-6-27 上午07:32:00 */public class RotateAnimation extends Animation {/** 值为true时可明确查看动画的旋转方向。 */public static final boolean DEBUG = false;/** 沿Y轴正方向看，数值减1时动画逆时针旋转。 */public static final boolean ROTATE_DECREASE = true;/** 沿Y轴正方向看，数值减1时动画顺时针旋转。 */public static final boolean ROTATE_INCREASE = false;/** Z轴上最大深度。 */public static final float DEPTH_Z = 310.0f;/** 动画显示时长。 */public static final long DURATION = 800l;/** 图片翻转类型。 */private final boolean type;private final float centerX;private final float centerY;private Camera camera;/** 用于监听动画进度。当值过半时需更新txtNumber的内容。 */private InterpolatedTimeListener listener;public RotateAnimation(float cX, float cY, boolean type) {centerX = cX;centerY = cY;this.type = type;setDuration(DURATION);}public void initialize(int width, int height, int parentWidth, int parentHeight) {// 在构造函数之后、getTransformation()之前调用本方法。super.initialize(width, height, parentWidth, parentHeight);camera = new Camera();}public void setInterpolatedTimeListener(InterpolatedTimeListener listener) {this.listener = listener;}protected void applyTransformation(float interpolatedTime, Transformation transformation) {// interpolatedTime:动画进度值，范围为[0.0f,10.f]if (listener != null) {listener.interpolatedTime(interpolatedTime);}float from = 0.0f, to = 0.0f;if (type == ROTATE_DECREASE) {from = 0.0f;to = 180.0f;} else if (type == ROTATE_INCREASE) {from = 360.0f;to = 180.0f;}float degree = from + (to - from) * interpolatedTime;boolean overHalf = (interpolatedTime > 0.5f);if (overHalf) {// 翻转过半的情况下，为保证数字仍为可读的文字而非镜面效果的文字，需翻转180度。degree = degree - 180;}// float depth = 0.0f;float depth = (0.5f - Math.abs(interpolatedTime - 0.5f)) * DEPTH_Z;final Matrix matrix = transformation.getMatrix();camera.save();camera.translate(0.0f, 0.0f, depth);camera.rotateY(degree);camera.getMatrix(matrix);camera.restore();if (DEBUG) {if (overHalf) {matrix.preTranslate(-centerX * 2, -centerY);matrix.postTranslate(centerX * 2, centerY);}} else {//确保图片的翻转过程一直处于组件的中心点位置matrix.preTranslate(-centerX, -centerY);matrix.postTranslate(centerX, centerY);}}/** 动画进度监听器。 */public static interface InterpolatedTimeListener {public void interpolatedTime(float interpolatedTime);}}
