blocks|key|87084|text|尝试签入onWindowFocusChanged，它应该具有有效值：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|87085|public+void+onWindowFocusChanged+(boolean+hasFocus)+{+}|code-block|syntax|javascript|87086|我有一个类似的问题，我需要获得一个小部件的宽度和高度，这是一个函数，在这个函数中，我可以保证小部件报告的大小是正确的。|87087|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Try checking in onWindowFocusChanged and it should have valid values:

<pre><code>public void onWindowFocusChanged (boolean hasFocus) { }
</code></pre>

I had a similar issue where I needed to get width and height of a widget and this was the function in which I could guarantee the widget reported it's correct size.

blocks|key|87106|text|试着打电话|type|unstyled|depth|inlineStyleRanges|entityRanges|data|87107|culoide.measure(MeasureSpec.UNSPECIFIED,+MeasureSpec.UNSPECIFIED);|offset|length|style|CODE|87108|首先，然后尝试getWidth()和getHeight()|87109|entityMap^0|0|0|1U|0|7|A|I|B|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|P|8|@$D|Q|E|R|F|G]|$D|S|E|T|F|G]]|9|@]|A|$]]|$1|J|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|K|$]]

Try calling 

<code>culoide.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);</code> 

first, then try <code>getWidth()</code> and <code>getHeight()</code>

blocks|key|304420|text|必须等到第一次测量和布局之后，才能获得getWidth()和getHeight()的非零值。您可以使用ViewTreeObserver.OnGlobalLayouListener来实现这一点|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|304421|public+void+onViewCreated(final+View+view,+Bundle+saved)+{
++++super.onViewCreated(view,+saved);
++++view.getViewTreeObserver().addOnGlobalLayoutListener(new+OnGlobalLayoutListener()+{
++++++++public+void+onGlobalLayout()+{
++++++++++++if+(Build.VERSION.SDK_INT+>=+Build.VERSION_CODES.JELLY_BEAN)+{
++++++++++++++view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
++++++++++++}+else+{
++++++++++++++view.getViewTreeObserver().removeGlobalOnLayoutListener(this);
++++++++++++}

++++++++++++//+get+width+and+height+of+the+view
++++++++}
++++});
}|code-block|syntax|javascript|304422|entityMap|0|LINK|mutability|MUTABLE|url|http://developer.android.com/reference/android/view/ViewTreeObserver.OnGlobalLayoutListener.html^0|J|A|U|B|1F|12|1F|12|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|F|3|G|5|H|7|12|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

You must wait until after the first measure and layout in order to get nonzero values for <code>getWidth()</code> and <code>getHeight()</code>. You can do this with a <a href="http://developer.android.com/reference/android/view/ViewTreeObserver.OnGlobalLayoutListener.html"><code>ViewTreeObserver.OnGlobalLayouListener</code></a>

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

 // get width and height of the view
 }
 });
}
</code></pre>

blocks|key|87158|text|我的首选方法是将一个OnLayoutChangeListener添加到要跟踪其自身的视图中|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|87159|CustomView+customView+=+...

customView.addOnLayoutChangeListener(new+View.OnLayoutChangeListener()+{
++++@Override
++++public+void+onLayoutChange(View+v,+int+left,+int+top,+int+right,+int+bottom,+int+oldLeft,+int+oldTop,+int+oldRight,+int+oldBottom)+{
++++++++//+Make+changes
++++}
});|code-block|syntax|javascript|87160|如果只想要初始布局，可以在回调中移除监听器。|87161|entityMap^0|A|M|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

My preferred method is to add an <code>OnLayoutChangeListener</code> to the view that you want to track itself

<pre><code>CustomView customView = ...

customView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
 @Override
 public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
 // Make changes
 }
});
</code></pre>

You can remove the listener in the callback if you only want the initial layout.

blocks|key|304504|text|使用ViewTreeObserver.OnGlobalLayoutListener、View.post(Runnable+action)或onWindowFocusChanged()不是最好的解决方案。这篇article+(注意:我是本文的作者)解释了其中的原因，并使用基于View.OnLayoutChangeListener的doOnLayout+kotlin扩展提供了一个有效的解决方案。如果你想在Java语言中使用它，在文章中有一个指向doOnLayout源代码的链接，它非常简单，你也可以在Java语言中做类似的事情。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|304505|entityMap|0|LINK|mutability|MUTABLE|url|https://cheesecakelabs.com/blog/understanding-android-views-dimensions-set/^0|2|13|16|Q|1X|M|3T|R|4L|A|66|A|2V|7|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]|$9|U|A|V|B|C]|$9|W|A|X|B|C]|$9|Y|A|Z|B|C]]|D|@$9|10|A|11|1|12]]|E|$]]|$1|F|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

Using <code>ViewTreeObserver.OnGlobalLayoutListener</code>, <code>View.post(Runnable action)</code> or <code>onWindowFocusChanged()</code> isn't the best solution. This <a href="https://cheesecakelabs.com/blog/understanding-android-views-dimensions-set/" rel="nofollow noreferrer">article</a> (note: I am the author of this article) explains why and provides a working solution using <code>doOnLayout</code> kotlin extension, which is based on <code>View.OnLayoutChangeListener</code>. If you want it in Java, in the article there's a link to <code>doOnLayout</code> source code, it's very simple and you can do something similar in Java too.

blocks|key|87253|text|这真的很痛苦，特别是因为在片段生命周期中，您期望使用像onViewCreated这样的名称来表示视图已经准备好了。对于我来说，像这样获取fragment+view本身：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|87254|+override+fun+onViewCreated(view:+View,+savedInstanceState:+Bundle?)+{
++++++++++++super.onViewCreated(view,+savedInstanceState)+++
+++++getView()?.let{
++++++++++++++++++it.doOnLayout{//+do+your+UI+work+here+}
+++++++++++++++++++}
++++}|code-block|syntax|javascript|87255|这确保了片断getView实际上已经有了一个布局过程。|87256|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.android.com/reference/android/app/Fragment#getView()^0|1W|D|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

this is a real pain especially because you expected with a name like onViewCreated in fragments lifecycle that the view is ready. for me get the <a href="https://developer.android.com/reference/android/app/Fragment#getView()" rel="nofollow noreferrer">fragment view</a> itself like this:
<pre><code> override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
 super.onViewCreated(view, savedInstanceState) 
 getView()?.let{
 it.doOnLayout{// do your UI work here }
 }
 }
</code></pre>
this ensures the fragments getView has actually had one layout pass already.

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. 

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.

<pre><code> 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
}
</code></pre>

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.

Any help?

getWidth() and getHeight() always returning 0. Custom view

Java

在一个片段中，我使用多个子视图来扩展布局。我需要获取其中之一的尺寸(宽度和高度)，这是一个自定义视图。在自定义视图类中，我可以很容易地做到这一点。但是如果我尝试从片段开始，我总是得到0作为维度。 public void onViewCreated(View view, Bundle savedInstanceState...

问getWidth()和getHeight()总是返回0。自定义视图
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