如何在 Android Fragments 中添加操作栏选项菜单 [英] How to add Action bar options menu in Android Fragments

问题描述

我正在尝试在 Android Fragments 中有一个选项菜单.ActionBar 选项菜单未显示在我的片段中.

I am trying to have a options menu in Android Fragments. ActionBar options menu are not displaying in my Fragments.

这是我的代码，我有 onCreateOptionsMenu() 和 onOptionSelected() 函数.我的代码没有显示任何错误.但是选项菜单没有显示.

Here is my code and I have both onCreateOptionsMenu() and onOptionSelected() function. My code doesn't shows any error. But options menu are not displaying.

package org.reachout;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;

import org.general.R;

public class ViewMessageFragment extends Fragment {

    /* (non-Javadoc)
     * @see android.support.v4.app.Fragment#onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)
     */
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        if (container == null) {
            // We have different layouts, and in one of them this
            // fragment's containing frame doesn't exist.  The fragment
            // may still be created from its saved state, but there is
            // no reason to try to create its view hierarchy because it
            // won't be displayed.  Note this is not needed -- we could
            // just run the code below, where we would create and return
            // the view hierarchy; it would just never be used.
            return null;
        }
        return (LinearLayout)inflater.inflate(R.layout.viewmessages_tab_fragment_layout, container, false);
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        // TODO Auto-generated method stub
        super.onCreateOptionsMenu(menu, inflater);
        inflater.inflate(R.menu.askexperts_menu, menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
       // handle item selection
       switch (item.getItemId()) {
          case R.id.action_settings:
             // do s.th.
             return true;
          default:
             return super.onOptionsItemSelected(item);
       }
    }   

}

推荐答案

你需要在onCreate()中调用setHasOptionsMenu(true).

为了向后兼容，最好在 onCreate() 的末尾或什至更晚的 onActivityCreated() 或类似的东西中尽可能晚地调用此调用.

For backwards compatibility it's better to place this call as late as possible at the end of onCreate() or even later in onActivityCreated() or something like that.

参见:https://developer.android.com/reference/android/app/Fragment.html#setHasOptionsMenu(boolean)

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