Android -- getWidth()与getMeasuredWidth()

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。

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