Android立体旋转动画实现与封装（支持以X、Y、Z三个轴为轴心旋转）

本文主要介绍Android立体旋转动画，或者3D旋转，下图是我自己实现的一个界面





立体旋转分为以下三种：

　　1. 以X轴为轴心旋转

　　2. 以Y轴为轴心旋转

　　3. 以Z轴为轴心旋转--这种等价于android默认自带的旋转动画RotateAnimation

实现立体旋转核心步骤：

　　1. 继承系统Animation重写applyTransformation方法

　　　　通过applyTransformation方法的回调参数 float interpolatedTime, Transformation t 来控制旋转动画

　　　　interpolatedTime 用来计算旋转角度而 t 用来控制变换矩阵从而实现图像的旋转

　　2. android.graphics.Camera控制旋转算法

　　　　Camera可以对图像执行一些比较复杂的操作--旋转，绽放，与Matrix一起实现图像的倾斜

核心代码封装：[b]Rotate3dAnimation[/b]

package rotateanim.example.com.androidrotateanim;

import android.view.animation.Animation;
import android.view.animation.Transformation;
import android.graphics.Camera;
import android.graphics.Matrix;

/**
* An animation that rotates the view on the X,Y,Z axis between two specified angles.
* This animation also adds a translation on the Z axis (depth) to improve the effect.
*/
public class Rotate3dAnimation extends Animation {
public static final Byte ROTATE_X_AXIS = 0x00;
public static final Byte ROTATE_Y_AXIS = 0x01;
public static final Byte ROTATE_Z_AXIS = 0x02;
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;
private Byte mRotateAxis;  // 0：X轴  1：Y轴  2：Z轴

/**创建3D旋转动画
* @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 depthZ the Z depth of the 3D rotation
* @param rotateAxis the rotate axis 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, Byte rotateAxis, boolean reverse) {
mFromDegrees = fromDegrees;
mToDegrees = toDegrees;
mCenterX = centerX;
mCenterY = centerY;
mDepthZ = depthZ;
mRotateAxis = rotateAxis;
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();
// 将当前的摄像头位置保存下来，以便变换进行完成后恢复成原位
        camera.save();
if (mReverse) {
// z的偏移会越来越大。这就会形成这样一个效果，view从近到远
 camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);
} else {
// z的偏移会越来越小。这就会形成这样一个效果，我们的View从一个很远的地方向我们移过来，越来越近，最终移到了我们的窗口上面
camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));
}
// 是给我们的View加上旋转效果，在移动的过程中，视图还会以XYZ轴为中心进行旋转。
if (ROTATE_X_AXIS.equals(mRotateAxis)) {
camera.rotateX(degrees);
} else if (ROTATE_Y_AXIS.equals(mRotateAxis)) {
camera.rotateY(degrees);
} else {
camera.rotateZ(degrees);
}

// 这个是将我们刚才定义的一系列变换应用到变换矩阵上面，调用完这句之后，我们就可以将camera的位置恢复了，以便下一次再使用。
camera.getMatrix(matrix);
// camera位置恢复
camera.restore();

 // 下面两句是为了动画是以View中心为旋转点
matrix.preTranslate(-centerX, -centerY);
matrix.postTranslate(centerX, centerY);
}
}

[b]Rotate3dAnimation使用：跟普通动画使用没区别，设置给一个View对象，启动动画就搞定[/b]

mRotateImgv就是需要旋转的View对象

// 以X轴为轴心旋转
private void rotateOnXCoordinate() {
float centerX = mRotateImgv.getWidth() / 2.0f;
float centerY = mRotateImgv.getHeight() / 2.0f;
float depthZ = 0f;
Rotate3dAnimation rotate3dAnimationX = new Rotate3dAnimation(0, 180, centerX, centerY, depthZ, Rotate3dAnimation.ROTATE_X_AXIS, true);
rotate3dAnimationX.setDuration(1000);
mRotateImgv.startAnimation(rotate3dAnimationX);
}

// 以X轴为轴心旋转
private void rotateOnYCoordinate() {
float centerX = mRotateImgv.getWidth() / 2.0f;
float centerY = mRotateImgv.getHeight() / 2.0f;
float centerZ = 0f;

Rotate3dAnimation rotate3dAnimationX = new Rotate3dAnimation(0, 180, centerX, centerY, centerZ, Rotate3dAnimation.ROTATE_Y_AXIS, true);
rotate3dAnimationX.setDuration(1000);
mRotateImgv.startAnimation(rotate3dAnimationX);
}

// 以Z轴为轴心旋转---等价于普通平面旋转动画
private void rotateAnimHorizon() {
float centerX = mRotateImgv.getWidth() / 2.0f;
float centerY = mRotateImgv.getHeight() / 2.0f;
float centerZ = 0f;

Rotate3dAnimation rotate3dAnimationX = new Rotate3dAnimation(180, 0, centerX, centerY, centerZ, Rotate3dAnimation.ROTATE_Z_AXIS, true);
rotate3dAnimationX.setDuration(1000);
mRotateImgv.startAnimation(rotate3dAnimationX);

// 下面是使用android自带的旋转动画
// RotateAnimation rotateAnimation = new RotateAnimation(0, 180, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
// rotateAnimation.setDuration(1000);
// mRotateImgv.startAnimation(rotateAnimation);
}