Android编程实现3D旋转效果实例

package com.android.graphics;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Camera;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
public class MainView extends View{
   //Camera类
   private Camera mCamera;
   private Bitmap face;
   private Matrix mMatrix = new Matrix();
   private Paint mPaint = new Paint();
   private int mLastMotionX, mLastMotionY;
   //图片旋转时的中心点坐标
   private int centerX, centerY;
   //转动的总距离，跟度数比例1:1
   private int deltaX, deltaY;
   //图片宽度高度
   private int bWidth, bHeight;
   public MainView(Context context,AttributeSet attributeSet) {
   super(context,attributeSet);
   setWillNotDraw(false);
   mCamera = new Camera();
   mPaint.setAntiAlias(true);
   face = BitmapFactory.decodeResource(getResources(), R.drawable.x);
   bWidth = face.getWidth();
   bHeight = face.getHeight();
   centerX = bWidth>>1;
   centerY = bHeight>>1;
   }
   void rotate(int degreeX, int degreeY) {
   deltaX += degreeX;
   deltaY += degreeY;
   mCamera.save();
   mCamera.rotateY(deltaX);
   mCamera.rotateX(-deltaY);
   mCamera.translate(0, 0, -centerX);
   mCamera.getMatrix(mMatrix);
   mCamera.restore();
   //以图片的中心点为旋转中心,如果不加这两句，就是以（0,0）点为旋转中心
   mMatrix.preTranslate(-centerX, -centerY);
   mMatrix.postTranslate(centerX, centerY);
   mCamera.save();
   postInvalidate();
   }
   @Override
   public boolean onTouchEvent(MotionEvent event) {
   int x = (int) event.getX();
   int y = (int) event.getY();
   switch(event.getAction()) {
   case MotionEvent.ACTION_DOWN:
    mLastMotionX = x;
    mLastMotionY = y;
    break;
   case MotionEvent.ACTION_MOVE:
    int dx = x - mLastMotionX;
    int dy = y - mLastMotionY;
    rotate(dx, dy);
    mLastMotionX = x;
    mLastMotionY = y;
    break;
   case MotionEvent.ACTION_UP:
    break;
   }
   return true;
   }
   @Override
   public void dispatchDraw(Canvas canvas) {
   super.dispatchDraw(canvas);
   canvas.drawBitmap(face, mMatrix, mPaint);
   }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
 <com.android.graphics.MainView
  android:id="@+id/cv"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
 />
</LinearLayout>