这是我的当前代码
Path path_eclipse = new Path();
float radius = (float) (Math.sqrt(Math.pow(r.stopX - r.startX, 2.0f) + Math.pow(r.stopY - r.startY, 2.0f)) / 2.0f);
path_eclipse.addCircle(r.startX, r.startY, radius, Path.Direction.CCW);
canvas.drawPath(path_eclipse, paint);
使用这段代码,我得到的输出如下: 但我想画出像这样的圆形: 更新后的源代码:这段源代码在我的情况下有效 [已解决]
[OnDraw]
@Override
protected void onDraw(Canvas canvas) {
Path path_eclipse = new Path();
float centerX = (r.startX + r.stopX) /2;
float centerY = (r.startY + r.stopY) /2;
float radius = (float)Math.sqrt((r.stopX - r.startX)*(r.stopX - r.startX)+(r.stopY - r.startY)*(r.stopY - r.startY));
path_eclipse.addCircle(centerX, centerY, radius/2, Path.Direction.CCW);
canvas.drawPath(path_eclipse,paint);
}
[OnTouchEvent]
@Override
public boolean onTouchEvent(MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
startX = eventX;
startY = eventY;
return true;
case MotionEvent.ACTION_MOVE:
stopX = eventX;
stopY = eventY;
break;
case MotionEvent.ACTION_UP:
stopX = eventX;
stopY = eventY;
break;
default:
return false;
}
invalidate();
return true;
}