Android TV开发:实现3D仿Gallery效果的实例代码

public class Image3DSwitchView extends LinearLayout { 
 private int currentPage =0;//定义当前第几页 
 /** 
 * 图片左右两边的空白间距 
 */ 
 public static final int IMAGE_PADDING = 5; 
 private static final int TOUCH_STATE_REST = 0; 
 private static final int TOUCH_STATE_SCROLLING = 1; 
 /** 
 * 滚动到下一张图片的速度 
 */ 
 private static final int SNAP_VELOCITY = 600; 
 
 /** 
 * 表示滚动到下一张图片这个动作 
 */ 
 private static final int SCROLL_NEXT = 0; 
 /** 
 * 表示滚动到上一张图片这个动作 
 */ 
 private static final int SCROLL_PREVIOUS = 1; 
 /** 
 * 表示滚动回原图片这个动作 
 */ 
 private static final int SCROLL_BACK = 2; 
 private static Handler handler = new Handler(); 
 /** 
 * 控件宽度 
 */ 
 public static int mWidth; 
 private VelocityTracker mVelocityTracker;//主要用跟踪触摸屏事件(flinging事件和其他gestures手势事件)的速率 
 private Scroller mScroller; 
 /** 
 * 图片滚动监听器，当图片发生滚动时回调这个接口 
 */ 
 private OnImageSwitchListener mListener; 
 /** 
 * 记录当前的触摸状态 
 */ 
 private int mTouchState = TOUCH_STATE_REST; 
 /** 
 * 记录被判定为滚动运动的最小滚动值 
 */ 
 private int mTouchSlop; 
 /** 
 * 记录控件高度 
 */ 
 private int mHeight; 
 /** 
 * 记录每张图片的宽度 
 */ 
 private int mImageWidth; 
 /** 
 * 记录图片的总数量 
 */ 
 private int mCount; 
 /** 
 * 记录当前显示图片的坐标 
 */ 
 private int mCurrentImage; 
 /** 
 * 记录上次触摸的横坐标值 
 */ 
 private float mLastMotionX; 
 /** 
 * 是否强制重新布局 
 */ 
 private boolean forceToRelayout; 
 private int[] mItems; 
 public Image3DSwitchView(Context context, AttributeSet attrs) { 
 super(context, attrs); 
 mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop(); 
 mScroller = new Scroller(context); 
 //设置可以获得焦点 
 setFocusable(true); 
 } 
 @Override 
 protected void onLayout(boolean changed, int l, int t, int r, int b) { 
 if (changed || forceToRelayout) { 
 mCount = getChildCount(); 
 // 图片数量必须大于5，不然无法正常显示 
 if (mCount = 0 && mCurrentImage  mTouchSlop) { 
 mTouchState = TOUCH_STATE_SCROLLING; 
 } 
 break; 
 case MotionEvent.ACTION_UP: 
 default: 
 mTouchState = TOUCH_STATE_REST; 
 break; 
 } 
 return mTouchState != TOUCH_STATE_REST; 
 } 
 @Override 
 public void computeScroll() { 
 if (mScroller.computeScrollOffset()) { 
 scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); 
 refreshImageShowing(); 
 postInvalidate(); 
 } 
 } 
 /** 
 * 设置图片滚动的监听器，每当有图片滚动时会回调此接口。 
 * 
 * @param listener 图片滚动监听器 
 */ 
 public void setOnImageSwitchListener(OnImageSwitchListener listener) { 
 mListener = listener; 
 } 
 /** 
 * 设置当前显示图片的下标，注意如果该值小于零或大于等于图片的总数量，图片则无法正常显示。 
 * 
 * @param currentImage 图片的下标 
 */ 
 public void setCurrentImage(int currentImage) { 
 mCurrentImage = currentImage; 
 requestLayout(); 
 } 
 /** 
 * 滚动到下一张图片。 
 */ 
 public void scrollToNext() { 
 if (mScroller.isFinished()) { 
 currentPage++; 
 int disX = mImageWidth - getScrollX(); 
 checkImageSwitchBorder(SCROLL_NEXT); 
 if (mListener != null) { 
 mListener.onImageSwitch(mCurrentImage); 
 } 
 beginScroll(getScrollX(), 0, disX, 0, SCROLL_NEXT); 
 } 
 } 
 /** 
 * 滚动到上一张图片。 
 */ 
 public void scrollToPrevious() { 
 if (mScroller.isFinished()) { 
 if (currentPage ==0){ 
 currentPage = 7; 
 }else 
 currentPage--; 
 int disX = -mImageWidth - getScrollX(); 
 checkImageSwitchBorder(SCROLL_PREVIOUS); 
 if (mListener != null) { 
 mListener.onImageSwitch(mCurrentImage); 
 } 
 beginScroll(getScrollX(), 0, disX, 0, SCROLL_PREVIOUS); 
 } 
 } 
 /** 
 * 滚动回原图片。 
 */ 
 public void scrollBack() { 
 if (mScroller.isFinished()) { 
 beginScroll(getScrollX(), 0, -getScrollX(), 0, SCROLL_BACK); 
 } 
 } 
 /** 
 * 回收所有图片对象，释放内存。 
 */ 
 public void clear() { 
 for (int i = 0; i  mCount - 1) { 
 index = index - mCount; 
 } 
 return index; 
 } 
 /** 
 * 刷新所有图片的显示状态，包括当前的旋转角度。 
 */ 
 private void refreshImageShowing() { 
 for (int i = 0; i = mCount) { 
 mCurrentImage = 0; 
 } else if (action == SCROLL_PREVIOUS && --mCurrentImage  mImageWidth / 2; 
 } 
 /** 
 * 判断是否应该滚动到上一张图片。 
 */ 
 private boolean shouldScrollToPrevious(int velocityX) { 
 return velocityX > SNAP_VELOCITY || getScrollX() 

public class Image3DView extends ImageView { 
 /** 
 * 旋转角度的基准值 
 */ 
 private static final float BASE_DEGREE = 50f; 
 /** 
 * 旋转深度的基准值 
 */ 
 private static final float BASE_DEEP = 150f; 
 private Camera mCamera; 
 private Matrix mMaxtrix; 
 private Bitmap mBitmap; 
 /** 
 * 当前图片对应的下标 
 */ 
 private int mIndex; 
 /** 
 * 在前图片在X轴方向滚动的距离 
 */ 
 private int mScrollX; 
 /** 
 * Image3DSwitchView控件的宽度 
 */ 
 private int mLayoutWidth; 
 /** 
 * 当前图片的宽度 
 */ 
 private int mWidth; 
 /** 
 * 当前旋转的角度 
 */ 
 private float mRotateDegree; 
 /** 
 * 旋转的中心点 
 */ 
 private float mDx; 
 /** 
 * 旋转的深度 
 */ 
 private float mDeep; 
 public Image3DView(Context context, AttributeSet attrs) { 
 super(context, attrs); 
 mCamera = new Camera(); 
 mMaxtrix = new Matrix(); 
 //设置可获焦 & 可点击 
 setFocusable(true); 
 setClickable(true); 
 } 
 /** 
 * 初始化Image3DView所需要的信息，包括图片宽度，截取背景图等。 
 */ 
 public void initImageViewBitmap() { 
 if (mBitmap == null) { 
 //我们要获取cache首先要通过setDrawingCacheEnable方法开启cache，然后再调用getDrawingCache方法就可以获得view的cache图片了。 
 setDrawingCacheEnabled(true); 
 buildDrawingCache(); 
 mBitmap = getDrawingCache(); 
 } 
 mLayoutWidth = Image3DSwitchView.mWidth; 
 mWidth = getWidth() + Image3DSwitchView.IMAGE_PADDING * 2; 
 } 
 /** 
 * 设置旋转角度。 
 * 
 * @param index 当前图片的下标 
 * @param scrollX 当前图片在X轴方向滚动的距离 
 */ 
 public void setRotateData(int index, int scrollX) { 
 mIndex = index; 
 mScrollX = scrollX; 
 } 
 /** 
 * 回收当前的Bitmap对象，以释放内存。 
 */ 
 public void recycleBitmap() { 
 if (mBitmap != null && !mBitmap.isRecycled()) { 
 mBitmap.recycle(); 
 } 
 } 
 @Override 
 public void setImageResource(int resId) { 
 super.setImageResource(resId); 
 mBitmap = null; 
 initImageViewBitmap(); 
 } 
 @Override 
 public void setImageBitmap(Bitmap bm) { 
 super.setImageBitmap(bm); 
 mBitmap = null; 
 initImageViewBitmap(); 
 } 
 @Override 
 public void setImageDrawable(Drawable drawable) { 
 super.setImageDrawable(drawable); 
 mBitmap = null; 
 initImageViewBitmap(); 
 } 
 @Override 
 public void setImageURI(Uri uri) { 
 super.setImageURI(uri); 
 mBitmap = null; 
 initImageViewBitmap(); 
 } 
 @Override 
 protected void onDraw(Canvas canvas) { 
 if (mBitmap == null) { 
 // 如果Bitmap对象还不存在，先使用父类的onDraw方法进行绘制 
 super.onDraw(canvas); 
 } else { 
 if (isImageVisible()) { 
 // 绘图时需要注意，只有当图片可见的时候才进行绘制，这样可以节省运算效率 
 computeRotateData(); 
 mCamera.save(); 
 mCamera.translate(0.0f, 0.0f, mDeep); 
 mCamera.rotateY(mRotateDegree); 
 mCamera.getMatrix(mMaxtrix); 
 mCamera.restore(); 
 mMaxtrix.preTranslate(-mDx, -getHeight() / 2); 
 mMaxtrix.postTranslate(mDx, getHeight() / 2); 
 canvas.drawBitmap(mBitmap, mMaxtrix, null); 
 } 
 } 
 } 
 /** 
 * 在这里计算所有旋转所需要的数据。 
 */ 
 private void computeRotateData() { 
 float degreePerPix = BASE_DEGREE / mWidth; 
 float deepPerPix = BASE_DEEP / ((mLayoutWidth - mWidth) / 2); 
 switch (mIndex) { 
 case 0: 
 mDx = mWidth; 
 mRotateDegree = 360f - (2 * mWidth + mScrollX) * degreePerPix; 
 if (mScrollX  0) { 
 mDx = mWidth; 
 mRotateDegree = (360f - BASE_DEGREE) - mScrollX * degreePerPix; 
 mDeep = mScrollX * deepPerPix; 
 } else { 
 if (mScrollX  0) { 
 mDx = mWidth; 
 mRotateDegree = 360f - mScrollX * degreePerPix; 
 mDeep = 0; 
 if (mScrollX > mWidth) { 
 mDeep = (mScrollX - mWidth) * deepPerPix; 
 } 
 } else { 
 mDx = -Image3DSwitchView.IMAGE_PADDING * 2; 
 mRotateDegree = -mScrollX * degreePerPix; 
 mDeep = 0; 
 if (mScrollX  mWidth) { 
 mDx = mWidth; 
 mRotateDegree = 360f - (mScrollX - mWidth) * degreePerPix; 
 } else { 
 mDx = -Image3DSwitchView.IMAGE_PADDING * 2; 
 mRotateDegree = BASE_DEGREE - mScrollX * degreePerPix; 
 } 
 mDeep = 0; 
 } 
 break; 
 case 4: 
 mDx = -Image3DSwitchView.IMAGE_PADDING * 2; 
 mRotateDegree = (2 * mWidth - mScrollX) * degreePerPix; 
 if (mScrollX > mWidth) { 
 mDeep = 0; 
 } else { 
 mDeep = (mWidth - mScrollX) * deepPerPix; 
 } 
 break; 
 } 
 } 
 /** 
 * 判断当前图片是否可见。 
 * 
 * @return 当前图片可见返回true，不可见返回false。 
 */ 
 private boolean isImageVisible() { 
 boolean isVisible = false; 
 switch (mIndex) { 
 case 0: 
 if (mScrollX  (mLayoutWidth - mWidth) / 2) { 
 isVisible = false; 
 } else { 
 isVisible = true; 
 } 
 break; 
 case 2: 
 if (mScrollX > mLayoutWidth / 2 + mWidth / 2 
 || mScrollX  mWidth - (mLayoutWidth - mWidth) / 2) { 
 isVisible = true; 
 } else { 
 isVisible = false; 
 } 
 break; 
 } 
 return isVisible; 
 } 
} 

public class MainActivity extends AppCompatActivity { 
 private Button btn; 
 private Image3DSwitchView image3DSwitchView; 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.activity_main); 
 btn = (Button) findViewById(R.id.btn); 
 image3DSwitchView = (Image3DSwitchView) findViewById(R.id.image_switch_view); 
 btn.setOnKeyListener(new View.OnKeyListener() { 
 @Override 
 public boolean onKey(View v, int keyCode, KeyEvent event) { 
 if (keyCode == KeyEvent.KEYCODE_DPAD_UP && event.getAction()== KeyEvent.ACTION_DOWN) 
 image3DSwitchView.requestFocus(); 
 return true; 
 } 
 }); 
 //设置监听，并实现接口 
 image3DSwitchView.setonFocusListener(new Image3DSwitchView.OnFocusListener() { 
 @Override 
 public void onFocus() { 
 btn.requestFocus(); 
 } 
 @Override 
 public void setValue(String value) { 
 btn.setText(value+"/7"); 
 } 
 
 }); 
 } 
} 

@Override 
 public boolean dispatchKeyEvent(KeyEvent event) { 
 if (event.getAction() == KeyEvent.ACTION_DOWN){ 
 switch (event.getKeyCode()){ 
 //按下键 响应回调 
 case KeyEvent.KEYCODE_DPAD_DOWN: 
 if (onFocusListener != null){onFocusListener.onFocus();} 
 break; 
 //按确定键 
 case KeyEvent.KEYCODE_DPAD_CENTER: 
 Toast.makeText(getContext(),"点击了图片"+(currentPage%7+1),Toast.LENGTH_SHORT).show(); 
 break; 
 //右键 
 case KeyEvent.KEYCODE_DPAD_RIGHT: 
 scrollToNext(); 
 if (onFocusListener !=null){ 
 onFocusListener.setValue((currentPage%7+1)+""); 
 } 
 break; 
 //左键 
 case KeyEvent.KEYCODE_DPAD_LEFT: 
 scrollToPrevious(); 
 if (onFocusListener !=null){ 
 onFocusListener.setValue((currentPage%7+1)+""); 
 } 
 break; 
 } 
 } 
 return true; 
 } 

setFocusable(true); 

public interface OnFocusListener{ 
 void onFocus();//处理焦点 
 void setValue(String value);//处理当前页码 
} 
private OnFocusListener onFocusListener; 
public void setonFocusListener(OnFocusListener onFocusListener){ 
 this.onFocusListener = onFocusListener; } 
@Override 
public boolean dispatchKeyEvent(KeyEvent event) { 
 if (event.getAction() == KeyEvent.ACTION_DOWN){ 
 switch (event.getKeyCode()){ 
 //按下键 响应回调 
 case KeyEvent.KEYCODE_DPAD_DOWN: 
 if (onFocusListener != null){onFocusListener.onFocus();} 
 break; 
 //按确定键 
 case KeyEvent.KEYCODE_DPAD_CENTER: 
 Toast.makeText(getContext(),"点击了图片"+(currentPage%7+1),Toast.LENGTH_SHORT).show(); 
 break; 
 //右键 
 case KeyEvent.KEYCODE_DPAD_RIGHT: 
 scrollToNext(); 
 if (onFocusListener !=null){ 
 onFocusListener.setValue((currentPage%7+1)+""); 
 } 
 break; 
 //左键 
 case KeyEvent.KEYCODE_DPAD_LEFT: 
 scrollToPrevious(); 
 if (onFocusListener !=null){ 
 onFocusListener.setValue((currentPage%7+1)+""); 
 } 
 break; 
 } 
 } 
 return true; 
} 

image3DSwitchView.setonFocusListener(new Image3DSwitchView.OnFocusListener() { 
 @Override 
 public void onFocus() { 
 btn.requestFocus();//让Image3DSwitchView控件下的按钮获得焦点 
 } 
 @Override 
 public void setValue(String value) { 
 btn.setText(value+"/7");//给按钮设置 第几页/共几页 
 } 
 });