android 細節之 旋轉動畫

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Flip Animation for Android:

近期項目中用到了一個小動畫，讓物體實現一定的3D旋轉效果，現記錄例如以下：

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);    }}

android 細節之 旋轉動畫