setContentView和LayoutInflater有什么区别? [英] What is the difference between setContentView and LayoutInflater?

问题描述

我正在创建带有几个片段的标签列表. 我注意到，在主要活动中，我使用setContentView获取布局xml，并使用findViewById获取相应的UI元素配置.

setContentView(R.layout.fragment_tabs);
mTabHost = (TabHost)findViewById(android.R.id.tabhost);
mTabHost.setup();
mTabManager = new TabManager(this, mTabHost, android.R.id.tabcontent);

但是，在不同的片段类中，我不得不使用充气机.

View v = inflater.inflate(R.layout.webview, container, false);
WebView myBrowser=(WebView)v.findViewById(R.id.mybrowser);

这两个函数都用于获取布局xml来创建对象，为什么会有区别?是onCreate期间的第一个用途，而onCreateView期间的第二个用途?在什么情况下我应该选择其中一个?

解决方案

setContentView仅是Activity方法.每个Activity都提供一个ID为"@+id/content"的FrameLayout(即内容视图).您在setContentView中指定的任何视图将是该Activity的视图.请注意，您还可以将视图实例传递给此方法，例如setContentView(new WebView(this));您所使用的方法的版本将在后台为您放大视图.

另一方面，片段具有称为onCreateView的生命周期方法，该方法返回一个视图(如果有一个视图).最常见的方法是用XML扩展视图并以此方法返回它.在这种情况下，您需要自己充气.片段没有setContentView方法

I am creating a tabs list with several fragments. I have noticed that, in the main activity, I used setContentView to get the layout xml and use findViewById to get the corresponding UI element config.

setContentView(R.layout.fragment_tabs);
mTabHost = (TabHost)findViewById(android.R.id.tabhost);
mTabHost.setup();
mTabManager = new TabManager(this, mTabHost, android.R.id.tabcontent);

However, in the different fragment class, I have to use the inflater instead.

View v = inflater.inflate(R.layout.webview, container, false);
WebView myBrowser=(WebView)v.findViewById(R.id.mybrowser);

And both function are used to get the layout xml to create an object, why is there a difference? Is the first one use during onCreate, and the second one during onCreateView? In what situation I should choose either of them?

解决方案

setContentView is an Activity method only. Each Activity is provided with a FrameLayout with id "@+id/content" (i.e. the content view). Whatever view you specify in setContentView will be the view for that Activity. Note that you can also pass an instance of a view to this method, e.g. setContentView(new WebView(this)); The version of the method that you are using will inflate the view for you behind the scenes.

Fragments, on the other hand, have a lifecycle method called onCreateView which returns a view (if it has one). The most common way to do this is to inflate a view in XML and return it in this method. In this case you need to inflate it yourself though. Fragments don't have a setContentView method

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