当视图完全被绘制时，用于获取通知的痛苦监听器对于 Kotlins 扩展来说是如此简单和令人敬畏

mView.afterMeasured {
  // inside this block the view is completely drawn
  // you can get view's height/width, it.height / it.width
}

在引擎盖下

inline fun View.afterMeasured(crossinline f: View.() -> Unit) {
viewTreeObserver.addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener {
    override fun onGlobalLayout() {
        if (measuredHeight > 0 && measuredWidth > 0) {
            viewTreeObserver.removeOnGlobalLayoutListener(this)
            f()
        }
    }
})
}