/** Created by xuzhilei on 2016/8/16. 模仿音樂暫停開始按鈕的View */public class PlayButtonView extends View {  /** 中心點X軸坐標 */ private int viewCenterX;  /** 中心點Y軸坐標 */ private int viewCenterY;  /** 有效長度的一般（View長寬較小者的一半） */ private int viewHalfLength;  /** 三角形右側頂點 */ private Point pointA = new Point();  /** 三角形左上頂點 */ private Point pointB = new Point();  /** 三角形左下頂點 */ private Point pointC = new Point();  /** 矩形左邊界 */ private int RectLeft;  /** 矩形上邊界 */ private int RectTOP;  /** 矩形右邊界 */ private int RectRight;  /** 矩形下邊界 */ private int RectBottom;  /** 三角形的三條邊路徑 */ private Path path = new Path();  /** 包圍最外側圓環的矩形 */ private RectF rectF = new RectF();  /** 包圍進度圓弧的矩形 */ private RectF rectF2 = new RectF();  /** 進度 */ private int progress;  /** 暫停中還是播放中 */ private boolean isPlaying = false;  /** 是否進行過了測量 */ private boolean isMeasured = false;  /** 畫筆顏色 */ private int color = 0xffff0099;  /** 最外側圓環畫筆 */ private Paint paintA = new Paint();  /** 進度圓弧畫筆 */ private Paint paintB = new Paint();  /** 暫停開始畫筆 */ private Paint paintC = new Paint();  /** 狀態監聽器 */ private OnStatusChangeListener onStatusChangeListener;  /** 構造器 */ public PlayButtonView(Context context, AttributeSet attrs) { super(context, attrs); }  @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (!isMeasured) {  getWidthAndHeight();  isMeasured = true; } }  /** 得到視圖等的高度寬度尺寸數據 */ private void getWidthAndHeight() {  int viewHeight = getMeasuredHeight(); int viewWidth = getMeasuredWidth(); viewCenterX = viewWidth / 2; viewCenterY = viewHeight / 2; viewHalfLength = viewHeight < viewWidth ? viewHeight / 2 : viewWidth / 2;  int paintAwidth = viewHalfLength / 15; int paintBwidth = viewHalfLength / 8;  rectF.left = viewCenterX - (viewHalfLength - paintAwidth / 2); rectF.top = viewCenterY - (viewHalfLength - paintAwidth / 2); rectF.right = viewCenterX + (viewHalfLength - paintAwidth / 2); rectF.bottom = viewCenterY + (viewHalfLength - paintAwidth / 2);  rectF2.left = viewCenterX - (viewHalfLength - paintBwidth / 2); rectF2.top = viewCenterY - (viewHalfLength - paintBwidth / 2); rectF2.right = viewCenterX + (viewHalfLength - paintBwidth / 2); rectF2.bottom = viewCenterY + (viewHalfLength - paintBwidth / 2);  paintA.setColor(color); paintA.setStrokeWidth(paintAwidth); paintA.setAntiAlias(true); paintA.setStyle(Paint.Style.STROKE);  paintB.setColor(color); paintB.setStrokeWidth(paintBwidth); paintB.setAntiAlias(true); paintB.setStyle(Paint.Style.STROKE);  paintC.setColor(color); paintC.setStrokeWidth(1); paintC.setAntiAlias(true); paintC.setStyle(Paint.Style.FILL);  pointA.x = viewCenterX + viewHalfLength / 2; pointA.y = viewCenterY;  double sin = Math.sin(Math.toRadians(60)); // √(3) / 2 double cos = Math.cos(Math.toRadians(60)); // 1/ 2  pointB.x = (float) ((viewCenterX - cos * viewHalfLength + viewCenterX) / 2); pointB.y = (float) ((viewCenterY - sin * viewHalfLength + viewCenterY) / 2);  pointC.x = (float) ((viewCenterX - cos * viewHalfLength + viewCenterX) / 2); pointC.y = (float) ((viewCenterY + sin * viewHalfLength + viewCenterY) / 2);  RectLeft = viewCenterX - viewHalfLength / 3; RectTOP = viewCenterY - viewHalfLength / 3; RectRight = viewCenterX + viewHalfLength / 3; RectBottom = viewCenterY + viewHalfLength / 3; }  @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas);  // 畫未完成進度的圓環 canvas.drawArc(rectF, 0, 360, false, paintA);  // 畫已經完成進度的圓弧 從-90度開始，即從圓環頂部開始 canvas.drawArc(rectF2, -90, progress * 3.6f, false, paintB);  if (isPlaying) {  canvas.drawRect(RectLeft, RectTOP, RectRight, RectBottom, paintC); } else {  path.reset();  path.moveTo(pointA.x, pointA.y);  path.lineTo(pointB.x, pointB.y);  path.lineTo(pointC.x, pointC.y);  path.close();  canvas.drawPath(path, paintC); } }  /** 監聽觸摸DOWN時間，開始播放，暫停播放 */ @Override public boolean onTouchEvent(MotionEvent event) {  if (event.getAction() == MotionEvent.ACTION_DOWN) {  isPlaying = !isPlaying;  invalidate();  if (isPlaying) {  onStatusChangeListener.play();  } else {  onStatusChangeListener.pause();  } } return super.onTouchEvent(event); }  /** 設置進度 0-100區間 */ public void setProgress(int progress) {  if (progress < 0) {  progress = 0; } if (progress > 100) {  progress = 100; } this.progress = progress; invalidate(); }  /** 外界設置播放狀態 */ public void setPlaying(boolean isPlaying) { this.isPlaying = isPlaying; invalidate(); }  /** 播放暫停狀態監聽的接口 */ public interface OnStatusChangeListener {  void play();  void pause(); }  /** 設置監聽接口 */ public void setOnStatusChangeListener(OnStatusChangeListener onStatusChangeListener) { this.onStatusChangeListener = onStatusChangeListener; }  /** 位置信息 */ private class Point { float x; float y; }