Rotate3dAnimation.java

The file containing the source code shown below is located in the corresponding directory in <sdk>/samples/android-<version>/...

译：下列包含源码的文件位于相应的<sdk>/samples/android-<version>/...目录下

package com.example.android.apis.animation;

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 Y axis between two specified angles.
 * This animation also adds a translation on the Z axis (depth) to improve the effect.
译: 一个在指定了两个角度的在Y轴旋转的动画类.
   这个类也添加了一个z轴的属性用来提高效果.
 */
publicclassRotate3dAnimationextendsAnimation{
    privatefinalfloat mFromDegrees;
    privatefinalfloat mToDegrees;
    privatefinalfloat mCenterX;
    privatefinalfloat mCenterY;
    privatefinalfloat mDepthZ;
    privatefinalboolean mReverse;
    privateCamera 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.
 在Y轴创建了一个新的3D的旋转动画,这个旋转动画定义了它的开始角度和结束角度,两个角度的单位都是度数
 ,这个旋转动画围绕在2D空间的中心点执行.你可以用X轴坐标(叫做centerX)和Y轴(叫做centerY)坐标来定
 义这个中心点.当动画开始时,对于z轴(深度)的转换就会被执行.转换的长度和转换正向反向都可以指定.

     * @param fromDegrees the start angle of the 3D rotation 开始的角度
     * @param toDegrees the end angle of the 3D rotation     结束的角度
     * @param centerX the X center of the 3D rotation        中心点X轴坐标
     * @param centerY the Y center of the 3D rotation        中心点Y轴坐标
     * @param reverse true if the translation should be reversed, false otherwise true表示反向,false表示正向
     */
    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
    publicvoid initialize(int width,int height,int parentWidth,int parentHeight){
        super.initialize(width, height, parentWidth, parentHeight);
        mCamera =newCamera();
    }

    @Override
    protectedvoid applyTransformation(float interpolatedTime,Transformation t){
        finalfloat fromDegrees = mFromDegrees;
        float degrees = fromDegrees +((mToDegrees - fromDegrees)* interpolatedTime);

        finalfloat centerX = mCenterX;
        finalfloat centerY = mCenterY;
        finalCamera camera = mCamera;

        finalMatrix 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);
    }
}