Android自定义View（三）路径效果PathEffect

1.七种路径效果

1.1 效果图

1.2 具体方法

• PathEffect();
  默认效果，就是直线

• CornerPathEffect(radius); 
  将各线段之间的夹角变成圆角，radius是圆角的半径

• new DashPathEffect(new float[]{10f, 5f, 20f, 15f},10);绘制虚线，intervals最少为2个，phase是偏移量 依次绘制为：实线10f + 虚线5f + 实线20f + 虚线10f

• new PathDashPathEffect(p, 60, 0, PathDashPathEffect.Style.ROTATE); 
  和DashPathEffect差不多，只是能自定义图形来绘制Path。 shape是绘制的图形、adwance是图形之间的间距、phase是偏移量、样式

• new SumPathEffect(pathEffects[1], pathEffects[2]); 
  将两种效果分别展示再重合

• new DiscretePathEffect(5f, 10f);
  切断线段，segmentLength是指切断线段的长度。deviation是偏移量，随机，小于等于deviation

• new ComposePathEffect(pathEffects[3], pathEffects[5]);
  将多个效果组合起来

1.3 Demo代码

private void initPaint() {
        //字体画笔
        textPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        textPaint.setColor(Color.WHITE);
        textPaint.setTextSize(40f);

        //线画笔
        linePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        linePaint.setColor(Color.RED);
        linePaint.setStrokeWidth(5f); //设置线宽
        linePaint.setStyle(Paint.Style.STROKE); //设置为空心

        //设置路径
        path = new Path();
        path.moveTo(0,0); //设置起点
        for (int i = 0; i < 37; i++) { //设置连接的点
            path.lineTo(i*30,(float) (Math.random() * 100));
        }

        //初始化路径效果 - 共有七种
        pathEffects = new PathEffect[7];
        pathEffects[0] = new PathEffect(); //1.默认效果
        pathEffects[1] = new CornerPathEffect(20f); 
        pathEffects[2] = new DashPathEffect(new float[]{10f, 5f, 20f, 15f},10); 
        Path p = new Path();
        p.addRect(0, 0, 30, 5, Path.Direction.CCW);
        pathEffects[3] = new PathDashPathEffect(p, 60,0,PathDashPathEffect.Style.ROTATE); 
        pathEffects[4] = new SumPathEffect(pathEffects[1], pathEffects[2]); 
        pathEffects[5] = new DiscretePathEffect(5f, 10f);
        pathEffects[6] = new ComposePathEffect(pathEffects[3], pathEffects[5]);
        setBackgroundColor(Color.BLUE);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //绘制路径
        for (int i = 0; i < pathEffects.length; i++) {
            linePaint.setPathEffect(pathEffects[i]); //设置路径效果
            canvas.drawPath(path,linePaint);
            canvas.drawText(pathEffectName[i],0,140,textPaint);
            //每绘制一条将画布向下平移180像素
            canvas.translate(0,150);
        }
        invalidate(); //绘制刷新
    }