【android】Rotate3dAnimation实现3D旋转动画

最近接触了动画方面点点滴滴，看到一个关于3D旋转动画方面蛮有趣的小按理，整理出来和大家分享一下。

先来看下效果：



3D效果的实现主要用过Camera，调用camera的rotateX()、rotateY()、rotateZ()方法并传入相应的角度使View能够绕坐标轴旋转，这个按理主要让一个ListView和一个ImageView绕y轴旋转。

首先，通过一个自定义Rotate3dAnimation类扩展之Animation类，并重写它的applyTransformation()方法以及提供指定时间的变换矩阵，通过camera类得到一个依据旋转轴旋转的matrix矩阵并将这个矩阵传入到Transformation对象中去。实现代码如下：

@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();

        camera.save();
        if (mReverse) {
            camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);
        } else {
            camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));
        }
        camera.rotateY(degrees);
        camera.getMatrix(matrix);
        camera.restore();

        matrix.preTranslate(-centerX, -centerY);
        matrix.postTranslate(centerX, centerY);
    }

在Activity的布局文件中奖ListView和ImageView放在同一个FrameLayout中，ListView和ImageView位置相互重叠，先后对两个View实现动画效果（ListVIew从0°旋转到90°或者ImageView实现从180°旋转到90°）需要注意一点的是：程序中通过mposition值的大小来判定在旋转后显示或者隐藏的是ListVIew还是ImageView。代码如下：

private final class DisplayNextView implements Animation.AnimationListener {
        private final int mPosition;

        private DisplayNextView(int position) {
            mPosition = position;
        }

        public void onAnimationStart(Animation animation) {
        }

        public void onAnimationEnd(Animation animation) {
            mContainer.post(new SwapViews(mPosition));
        }

        public void onAnimationRepeat(Animation animation) {
        }
    }

private final class SwapViews implements Runnable {
        private final int mPosition;

        public SwapViews(int position) {
            mPosition = position;
        }

        public void run() {
            final float centerX = mContainer.getWidth() / 2.0f;
            final float centerY = mContainer.getHeight() / 2.0f;
            Rotate3dAnimation rotation;
            
            if (mPosition > -1) {
                mPhotosList.setVisibility(View.GONE);
                mImageView.setVisibility(View.VISIBLE);
                mImageView.requestFocus();

                rotation = new Rotate3dAnimation(90, 180, centerX, centerY, 310.0f, false);
            } else {
                mImageView.setVisibility(View.GONE);
                mPhotosList.setVisibility(View.VISIBLE);
                mPhotosList.requestFocus();

                rotation = new Rotate3dAnimation(90, 0, centerX, centerY, 310.0f, false);
            }

            rotation.setDuration(500);
            rotation.setFillAfter(true);
            rotation.setInterpolator(new DecelerateInterpolator());

            mContainer.startAnimation(rotation);
        }
    }

另外，分别对listView和ImageView设置监听事件

public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
        // Pre-load the image then start the animation
        mImageView.setImageResource(PHOTOS_RESOURCES[position]);
        applyRotation(position, 0, 90);
    }

    public void onClick(View v) {
        applyRotation(-1, 180, 90);
    }

private void applyRotation(int position, float start, float end) {
        // Find the center of the container
        final float centerX = mContainer.getWidth() / 2.0f;
        final float centerY = mContainer.getHeight() / 2.0f;

        // Create a new 3D rotation with the supplied parameter
        // The animation listener is used to trigger the next animation
        final Rotate3dAnimation rotation =
                new Rotate3dAnimation(start, end, centerX, centerY, 310.0f, true);
        rotation.setDuration(500);
        rotation.setFillAfter(true);
        rotation.setInterpolator(new AccelerateInterpolator());
        rotation.setAnimationListener(new DisplayNextView(position));

        mContainer.startAnimation(rotation);
    }

文章最后附上自定义Rotate3dAnimation完整代码如下：

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;

    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();

        camera.save();
        if (mReverse) {
            camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);
        } else {
            camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));
        }
        camera.rotateY(degrees);
        camera.getMatrix(matrix);
        camera.restore();

        matrix.preTranslate(-centerX, -centerY);
        matrix.postTranslate(centerX, centerY);
    }
}