public class Rotate3D extends Animation {   private float fromDegree;  // 旋轉起始角度   private float toDegree;   // 旋轉終止角度   private float mCenterX;   // 旋轉中心x   private float mCenterY;   // 旋轉中心y   private Camera mCamera;   public Rotate3D(float fromDegree, float toDegree, float centerX, float centerY) {     this.fromDegree = fromDegree;     this.toDegree = toDegree;     this.mCenterX = centerX;     this.mCenterY = centerY;   }   @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 FromDegree = fromDegree;     float degrees = FromDegree + (toDegree - fromDegree) * interpolatedTime;  // 旋轉角度（angle）     final float centerX = mCenterX;     final float centerY = mCenterY;     final Matrix matrix = t.getMatrix();     if (degrees <= -76.0f) {       degrees = -90.0f;       mCamera.save();       mCamera.rotateY(degrees); // 旋轉       mCamera.getMatrix(matrix);       mCamera.restore();     } else if (degrees >= 76.0f) {       degrees = 90.0f;       mCamera.save();       mCamera.rotateY(degrees);       mCamera.getMatrix(matrix);       mCamera.restore();     } else {       mCamera.save();       mCamera.translate(0, 0, centerX); // 位移x       mCamera.rotateY(degrees);       mCamera.translate(0, 0, -centerX);       mCamera.getMatrix(matrix);       mCamera.restore();     }     matrix.preTranslate(-centerX, -centerY);     matrix.postTranslate(centerX, centerY);   } }

public void initAnimation() {   // 獲取旋轉中心   DisplayMetrics dm = new DisplayMetrics();   dm = getResources().getDisplayMetrics();   mCenterX = dm.widthPixels / 2;   mCenterY = dm.heightPixels / 2;   // 定義旋轉方向   int duration = 1000;   lQuest1Animation = new Rotate3D(0, -90, mCenterX, mCenterY);  // 下一頁的【question1】旋轉方向（從0度轉到-90，參考系為水平方向為0度）   lQuest1Animation.setFillAfter(true);   lQuest1Animation.setDuration(duration);   lQuest2Animation = new Rotate3D(90, 0, mCenterX, mCenterY);   // 下一頁的【question2】旋轉方向（從90度轉到0，參考系為水平方向為0度）（起始第一題）   lQuest2Animation.setFillAfter(true);   lQuest2Animation.setDuration(duration);   rQuest1Animation = new Rotate3D(0, 90, mCenterX, mCenterY);   // 上一頁的【question1】旋轉方向（從0度轉到90，參考系為水平方向為0度）   rQuest1Animation.setFillAfter(true);   rQuest1Animation.setDuration(duration);   rQuest2Animation = new Rotate3D(-90, 0, mCenterX, mCenterY);  // 上一頁的【question2】旋轉方向（從-90度轉到0，參考系為水平方向為0度）   rQuest2Animation.setFillAfter(true);   rQuest2Animation.setDuration(duration); }

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   android:id="@+id/layout_main"   android:layout_width="fill_parent"   android:layout_height="wrap_content"         android:orientation="vertical"> ... </LinearLayout>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   android:id="@+id/layout_next"   android:layout_width="fill_parent"   android:layout_height="wrap_content"         android:orientation="vertical"> ... </LinearLayout>

private void initMain(){     setContentView(R.layout.main);   layoutmain = (LinearLayout)findViewById(R.id.layout_main);   btn_MainLast = (Button)findViewById(R.id.main_last);   btn_MainNext = (Button)findViewById(R.id.main_next);   btn_MainLast.setOnClickListener(listener);   btn_MainNext.setOnClickListener(listener); } private void initNext(){     setContentView(R.layout.next);   layoutnext = (LinearLayout)findViewById(R.id.layout_next);   btn_NextLast = (Button)findViewById(R.id.next_last);   btn_NextNext = (Button)findViewById(R.id.next_next);   btn_NextLast.setOnClickListener(listener);   btn_NextNext.setOnClickListener(listener); }

private View.OnClickListener listener = new View.OnClickListener() {   @Override   public void onClick(View v) {     switch (v.getId()) {     case R.id.main_last:  // 上一頁       layoutmain.startAnimation(lQuest1Animation);  // 當前頁向左旋轉（0，-90）       initNext();       layoutnext.startAnimation(lQuest2Animation);  // 下一頁向左旋轉（90, 0）       break;     case R.id.main_next:  // 下一頁       layoutmain.startAnimation(rQuest1Animation);  // 當前頁向右旋轉（0，90）       initNext();       layoutnext.startAnimation(rQuest2Animation);  // 下一頁向右旋轉（-90, 0）       break;     case R.id.next_last:       layoutnext.startAnimation(lQuest1Animation);       initMain();       layoutmain.startAnimation(lQuest2Animation);       break;     case R.id.next_next:       layoutnext.startAnimation(rQuest1Animation);       initMain();       layoutmain.startAnimation(rQuest2Animation);       break;     }   } };