绘制虚线

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本文链接： https://blog.csdn.net/weixin_43724742/article/details/102770707

public class DashedLineView extends View {
    private Context context;
    private boolean isVertical = false;
    private int color = 0xFF000000;
    private float width = 3;

    public DashedLineView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.context = context;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint paint = new Paint();
        paint.setStyle(Paint.Style.STROKE);
        paint.setColor(color);
        paint.setStrokeWidth(dip2px(context, width));
        Path path = new Path();
        path.moveTo(0, 0);
        if (isVertical) {
            path.lineTo(0, getMeasuredHeight());
        } else {
            path.lineTo(getMeasuredWidth(), 0);
        }
        PathEffect effects = new DashPathEffect(new float[]{50,100}, 0);
        paint.setPathEffect(effects);
        canvas.drawPath(path, paint);
    }

    public static int dip2px(Context context, float dpValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }
}

DashPathEffect参数的含义：

	//第一个参数是一个float数组，它必须包含一个以上的数，这些数字的含义是：
	//画50像素实线，留白100像素，再画150像素实线，留白200像素；
	//第二个参数名称是phase，可以看出它是相移的意思
	new DashPathEffect(new float[]{50, 100, 150, 200}, 0);