Android_(自定义view_3)

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int width, height;

//设置大小
int contentWidth = 200;
int contentHeight = 200;
width = getMeasurement(widthMeasureSpec, contentWidth);
height = getMeasurement(heightMeasureSpec, contentHeight);

//必须调用此方法
setMeasuredDimension(width, height);
}

/*
* 辅助设置大小的方法
*/
private int getMeasurement(int measureSpec, int contentSize) {
int specSize = MeasureSpec.getSize(measureSpec);
switch (MeasureSpec.getMode(measureSpec)) {
case MeasureSpec.AT_MOST:
return Math.min(specSize, contentSize);
case MeasureSpec.UNSPECIFIED:
return contentSize;
case MeasureSpec.EXACTLY:
return specSize;
default:
return 0;
}
}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
if (w != oldw || h != oldh) {
//如果大小有变，要重置中心点以及半径
mCenter.x = w / 2;
mCenter.y = h / 2;
mRadius = Math.min(mCenter.x, mCenter.y);
}
}