private class Leaf {  // 葉子的坐標  float x, y;  // 旋轉角度  int rotateAngle;  // 起始時間(ms)  long startTime; }

 //使葉子初始時間有間隔 int addTime; private Leaf getLeaf() {  Random random = new Random();  Leaf leaf = new Leaf();  //隨機初始化葉子初始角度  leaf.rotateAngle = random.nextInt(360);  //隨機初始化葉子啟動時間  addTime += random.nextInt((int) (cycleTime));  leaf.startTime = System.currentTimeMillis() + cycleTime + addTime;  return leaf; } private List<Leaf> getLeafs(int leafSize) {  List<Leaf> list = new LinkedList<Leaf>();  for (int i=0; i<leafSize; i++) {   list.add(getLeaf());  }  return list; }

 //獲取每片葉子在XY軸上的滑動值 private void getLocation(Leaf leaf) {  float betweenTime = leaf.startTime - System.currentTimeMillis();  //周期結束再加一個cycleTime  if(betweenTime < 0) {   leaf.startTime = System.currentTimeMillis() + cycleTime + new Random().nextInt((int) (cycleTime));   betweenTime = cycleTime;  }  //通過時間差計算出葉子的坐標  float fraction = (float) betweenTime / cycleTime;  float x = (int)(width * fraction);  leaf.x = x;  float w = (float) ((float) 2 * Math.PI / width);  int y = (int) (18 * Math.sin(w * x)) + (height-mLeafHeight)/2;  leaf.y = y; } //獲取每片葉子的旋轉角度 private void getRotate(Leaf leaf) {  float scale = ((leaf.startTime - System.currentTimeMillis())%cycleTime)/ (float)cycleTime;  int rotate = (int)(scale * 360);  leaf.rotateAngle = rotate; }

 @Override protected void onDraw(Canvas canvas) {  super.onDraw(canvas);  //畫葉子  int size = leafList.size();  for (int i=0; i<size; i++) {   Leaf leaf = leafList.get(i);   //獲取葉子坐標   getLocation(leaf);   //獲取葉子旋轉角度   getRotate(leaf);   canvas.save();   Matrix matrix = new Matrix();   //設置滑動   matrix.postTranslate(leaf.x, leaf.y);   //設置旋轉   matrix.postRotate(leaf.rotateAngle, leaf.x + mLeafWidth / 2, leaf.y + mLeafHeight / 2);   //添加葉子到畫布   canvas.drawBitmap(mLeafBitmap, matrix, new Paint());   canvas.restore();  }  //調用onDraw()重復滑動  postInvalidate(); }

public class LeafView extends View { private String TAG = "--------LeafView"; private Resources mResources; //背景圖、葉子 private Bitmap mLeafBitmap, bgBitmap; //整個控件的寬度和高度 private int width, height; private Paint bgPaint; private RectF bgRect; private Rect bgDestRect; //存放葉子lsit private List<Leaf> leafList; //葉子的寬和高 private int mLeafWidth, mLeafHeight; //葉子滑動一周的時間5秒 private final static long cycleTime = 5000; //葉子數量 private final static int leafNumber = 5; public LeafView(Context context, AttributeSet attrs) {  super(context, attrs);  mResources = getResources();  mLeafBitmap = ((BitmapDrawable) mResources.getDrawable(R.drawable.leaf, null)).getBitmap();  mLeafWidth = mLeafBitmap.getWidth();  mLeafHeight = mLeafBitmap.getHeight()  bgBitmap = ((BitmapDrawable) mResources.getDrawable(R.drawable.leaf_kuang, null)).getBitmap();  bgPaint = new Paint();  bgPaint.setColor(mResources.getColor(R.color.bg_color));  //獲取所有葉子的信息，放入list  leafList = getLeafs(leafNumber); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {  super.onSizeChanged(w, h, oldw, oldh);  width = w;  height = h;  bgDestRect = new Rect(0, 0 , width, height); } @Override protected void onDraw(Canvas canvas) {  super.onDraw(canvas);  bgRect = new RectF(0, 0 , width, height);  //畫背景顏色到畫布  canvas.drawRect(bgRect, bgPaint);  //畫背景圖片到畫布  canvas.drawBitmap(bgBitmap, null, bgDestRect, null);  //畫葉子  int size = leafList.size();  for (int i=0; i<size; i++) {   Leaf leaf = leafList.get(i);   //獲取葉子坐標   getLocation(leaf);   //獲取葉子旋轉角度   getRotate(leaf);   canvas.save();   Matrix matrix = new Matrix();   //設置滑動   matrix.postTranslate(leaf.x, leaf.y);   //設置旋轉   matrix.postRotate(leaf.rotateAngle, leaf.x + mLeafWidth / 2, leaf.y + mLeafHeight / 2);   //添加葉子到畫布   canvas.drawBitmap(mLeafBitmap, matrix, new Paint());   canvas.restore();  }  //調用onDraw()重復滑動  postInvalidate(); } //獲取每片葉子在XY軸上的滑動值 private void getLocation(Leaf leaf) {  float betweenTime = leaf.startTime - System.currentTimeMillis();  //周期結束再加一個cycleTime  if(betweenTime < 0) {   leaf.startTime = System.currentTimeMillis() + cycleTime + new Random().nextInt((int) (cycleTime));   betweenTime = cycleTime;  }  //通過時間差計算出葉子的坐標  float fraction = (float) betweenTime / cycleTime;  float x = (int)(width * fraction);  leaf.x = x;  float w = (float) ((float) 2 * Math.PI / width);  int y = (int) (18 * Math.sin(w * x)) + (height-mLeafHeight)/2;  leaf.y = y; } //獲取每片葉子的旋轉角度 private void getRotate(Leaf leaf) {  float scale = ((leaf.startTime - System.currentTimeMillis())%cycleTime)/ (float)cycleTime;  int rotate = (int)(scale * 360);  leaf.rotateAngle = rotate; } private class Leaf {  // 葉子的坐標  float x, y;  // 旋轉角度  int rotateAngle;  // 起始時間(ms)  long startTime; } private List<Leaf> getLeafs(int leafSize) {  List<Leaf> list = new LinkedList<Leaf>();  for (int i=0; i<leafSize; i++) {   list.add(getLeaf());  }  return list; } //使葉子初始時間有間隔 int addTime; private Leaf getLeaf() {  Random random = new Random();  Leaf leaf = new Leaf();  leaf.rotateAngle = random.nextInt(360);  addTime += random.nextInt((int) (cycleTime));  leaf.startTime = System.currentTimeMillis() + cycleTime + addTime;  return leaf; }}