如何在片段的父活动中访问片段的子视图? [英] How to access Fragment's child views inside fragment's parent Activity?

问题描述

我有一个支持的片段活动，它将加载差异片段.该片段有一些 textView 和 id = "score" 并且我想得到它的句柄但是 findViewById 用于 score 的 textView> 返回空值.为什么会这样?

I have a supported fragment activity which will load diff fragments. The fragment has some textView with id = "score" and I want to get its handle but findViewById for score's textView returns null. Why so?

textView放置在fragment中

textView is placed in fragment

public class MyActivity extends  extends ActionBarActivity
        implements NavigationDrawerFragment.NavigationDrawerCallbacks{

   private TextView scoreBoardTextView = null;

   protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_home);
     mNavigationDrawerFragment = (NavigationDrawerFragment)
                getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
     scoreBoardTextView = (TextView) findViewById(R.id.score); //this returns null
  }

    @Override
    public void onNavigationDrawerItemSelected(int position) {
      //set fragment    
    }

}

推荐答案

注意:

直接访问片段之外的片段视图不是一个好主意.您应该使用片段回调接口来处理这种情况并避免错误.以下方式有效，但不建议这样做，因为这不是一个好的做法.<小时>如果您想访问其父 Activity 内的 Fragment 的 TextView，那么您应该在您的 Fragment 中定义一个方法这样的类:

Note:

Directly accessing fragment's views outside fragment is not a good idea. You should use fragment callback interfaces to handle such cases and avoid bugs. The following way works but it is not recommended as it is not a good practice.

---

If you want to access the TextView of Fragment inside its parent Activity then you should define a method inside your Fragment class like this:

public class MyFragment extends Fragment {

    TextView mTextView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.activity_main, container, false);
        mTextView = (TextView) view.findViewById(R.id.textView1);
        return view;
    }

    public void setTextViewText(String value){
        mTextView.setText(value);
    }


}

现在你可以像这样在你的 Activity 中使用它:

Now you can use this inside your Activity like this:

myFragment.setTextViewText("foo");

这里的 myFragment 是 MyFragment 类型.

here myFragment is of type MyFragment.

如果你想访问整个TextView，那么你可以在MyFragment.java中定义一个这样的方法:

If you want to access the whole TextView then you can define a method like this inside MyFragment.java:

public TextView getTextView1(){
    return mTextView;
}

通过这种方式，您可以访问 TextView 本身.

By this you can access the TextView itself.

希望这有帮助.:)

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