Android PathMeasure.getSegment方法注意项

boolean getSegment (float startD, 
                float stopD, 
                Path dst, 
                boolean startWithMoveTo)

Given a start and stop distance, return in dst the intervening segment(s). If the segment is zero-length, return false, else return true. startD and stopD are pinned to legal values (0..getLength()). If startD >= stopD then return false (and leave dst untouched). Begin the segment with a moveTo if startWithMoveTo is true.

On KITKAT and earlier releases, the resulting path may not display on a hardware-accelerated Canvas. A simple workaround is to add a single operation to this path, such asdst.rLineTo(0, 0).

以上是官方文档的解释。

在使用该方法时要注意On KITKAT and earlier releases, the resulting path may not display on a hardware-accelerated Canvas. A simple workaround is to add a single operation to this path, such asdst.rLineTo(0, 0).这句话的解释。

这句话的意思是：在android KITKAT版本及之前的版本，该方法所获取到的path是无法被绘制显示出来的。要解决该问题的简单方法就是在所要获取的path上执行lineTo(0, 0) 或执行rLineTo(0, 0);

例子：

public void setDistance(float distance) {
        this.distance = distance;
        
        mDstPath.reset();
        mDstPath.lineTo(0, 0);
        mPathMeasure.getSegment(0, distance, mDstPath, true);
        invalidate();
    }