的getWidth（）和getHeight（）总是返回0。自定义视图

问题描述：

在一个片段，我用充气多个子视图的布局。我需要获得其中之一是一个自定义视图的尺寸（宽度和高度）。

In a Fragment, I am inflating a Layout with multiple child View. I need to get the dimensions (width and height) of one of them which is a custom view.

在自定义视图类的，我可以很容易地做到这一点。但是，如果我尝试从片段做到这一点，我总是得到0的尺寸。

Inside the custom view class I can do it easily. But if I try to do it from the fragment I always get 0 as dimensions.

 public void onViewCreated(View view, Bundle savedInstanceState) {

    super.onViewCreated(view, savedInstanceState);
    View culoide = view.findViewWithTag(DRAW_AREA_TAG);
    Log.d("event", "culoide is: "+culoide.getWidth()); // always 0
}

我想，onViewCreated应该是正确的地方得到它，但也出现这种情况。我试过super.onViewCreated之前，在调试它看起来像'findViewWithTag找到正确的观点，试图与API 7 V4只支持。

I figure that onViewCreated should be the right place to get it, but well this happens. I tried before super.onViewCreated, in debug it looks like 'findViewWithTag' finds the right view, tried with api 7 v4 support only.

任何帮助吗？

答

您必须等待，直到第一个测量和布局，以获取非零值的getWidth（）后和的getHeight（）。你可以做到这一点ViewTreeObserver.OnGlobalLayouListener$c$c>

You must wait until after the first measure and layout in order to get nonzero values for getWidth() and getHeight(). You can do this with a ViewTreeObserver.OnGlobalLayouListener

public void onViewCreated(View view, Bundle saved) {
    super.onViewCreated(view, saved);
    final ViewTreeObserver observer = view.getViewTreeObserver();
    observer.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
        public void onGlobalLayout() {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                observer.removeOnGlobalLayoutListener(this);
            } else {
                observer.removeGlobalOnLayoutListener(this);
            }

            // get width and height of the view
        }
    });
}

的getWidth（）和getHeight（）总是返回0。自定义视图

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