Android用Path类绘制路径

class MyView extends View {
    float phase;
    PathEffect[] effects = new PathEffect[7];
    int[] colors;
    private Paint paint;
    Path path;
    public MyView(Context context) {
      super(context);
      paint = new Paint();
      paint.setStyle(Paint.Style.STROKE);
      paint.setStrokeWidth(4);
      //创建并初始化Path
      path = new Path();
      path.moveTo(0, 0);
      for(int i = 1; i <= 15; i++) {
        //生成15个点，随机生成他们的Y坐标，并将它们连成一条Path
        path.lineTo(i*20, (float)Math.random()*60);
      }
      //初始化7个颜色
      colors = new int[]{Color.BLACK, Color.BLUE, Color.CYAN, Color.GREEN,
          Color.MAGENTA, Color.RED, Color.YELLOW};
    }
    @Override
    protected void onDraw(Canvas canvas) {
      //将背景色填充成白色
      canvas.drawColor(Color.WHITE);
      //----------下面开始初始化7中路径效果----------
      //不使用路径效果
      effects[0] = null;
      //使用CornerPathEffect路径效果
      effects[1] = new CornerPathEffect(10);
      //初始化(不连续的、离散的)DiscretePathEffect
      effects[2] = new DiscretePathEffect(3.0f, 5.0f);
      //初始化DashPathEffect
      effects[3] = new DashPathEffect(new float[]{20,10,5,10}, phase);
      //初始化PathDashPathEffects
      Path p = new Path();
      p.addRect(0, 0, 8, 8, Path.Direction.CCW);
      effects[4] = new PathDashPathEffect(p, 12, phase, 
          PathDashPathEffect.Style.ROTATE);
      //初始化ComposePathEffect
      effects[5] = new ComposePathEffect(effects[2], effects[4]);
      //初始化SumPathEffect
      effects[6] = new SumPathEffect(effects[4], effects[3]);
      //将画布移动到(8,8)处开始绘制
      canvas.translate(8, 8);
      //依次使用7中不同路径效果、7种不同的颜色来绘制路径
      for(int i = 0; i < effects.length; i++) {
        paint.setPathEffect(effects[i]);
        paint.setColor(colors[i]);
        canvas.drawPath(path, paint);
        canvas.translate(0, 60);
      }
      //改变phase值,形成动画效果
      phase += 1;
      invalidate();
    }
  }