android getWidth()和getMeasuredWidth()方法的区别
getWidth()
Return the width of the your view.
Returns
- The width of your view, in pixels.
源代码:
public final int getWidth() {
return mRight - mLeft;
}
getwidth返回的是右边坐标减轻坐标减去左边坐标,这要在布局之后才能确定它们的坐标,也就是说在布局后才能调用getwidth来获取。所以getWidth()获得的宽度是View在设定好布局后整个View的宽度。
getMeasuredWidth()
Return the full width measurement information for this view as computed by the most recent call to measure(int, int). This result is a bit mask as defined byMEASURED_SIZE_MASK and MEASURED_STATE_TOO_SMALL. This should be used during measurement and layout calculations only. Use getWidth() to see how wide a view is after layout.
Returns
The measured width of this view as a bit mask.
得到的是最近一次调用measure()方法测量后得到的是View的宽度,它应该仅仅用在测量和Layout的计算中。再看源码:
public final int getMeasuredWidth() {
return mMeasuredWidth & MEASURED_SIZE_MASK;
}
return The raw measured width of this view 获得的是原始的测量宽度。所以说getMeasuredWidth()是对View上的内容进行测量后得到的View内容占据的宽度。前提是你必须在父布局的onLayout()方法或者此View的onDraw()方法里调用measure(0,0);(measure中的参数的值你自己可以定义),否则你得到的结果和getWidth()得到的结果是一样的。
区别
getMeasuredWidth:对View上的内容进行测量后得到的View内容占据的宽度的。
getWidth:View在设定号布局后整个View的宽度。
使用场合
getMeasuredWidth:在自定义view重写onLayout时、在我们用layoutinflater动态加载view后想获得view的原始宽度时。
getWidth:一般在view已经布局后呈现出来了,想获取宽度时。