片段中的Android选项菜单

Question

我试图从一组片段添加一个项目到选项菜单.

我创建了一个新MenuFragment类,并为我希望包含菜单项的片段扩展了这个.这是代码:

public class MenuFragment extends Fragment {

    MenuItem fav;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);
    }

    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        fav = menu.add("add");
        fav.setIcon(R.drawable.btn_star_big_off);
    }
}

由于某种原因,onCreateOptionsMenu似乎没有运行.

Answer 1

调用超级方法:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    // TODO Add your menu entries here
    super.onCreateOptionsMenu(menu, inflater);
}

将日志语句放在代码中以查看是否未调用该方法,或者您的代码是否未修改该菜单.

此外,还要确保您呼叫setHasOptionsMenu(boolean)的onCreate(Bundle)通知,它应该参与选项菜单处理的片段.

Answer 2

我遇到了同样的问题,但我认为最好总结一下并介绍最后一步让它运转起来:

1. 在Fragment的onCreate(Bundle savedInstanceState)方法中添加setHasOptionsMenu(true)方法.

2. onCreateOptionsMenu(Menu menu, MenuInflater inflater)在片段中覆盖(如果你想在Fragment的菜单中做一些不同的事情)和onOptionsItemSelected(MenuItem item)方法.

3. 在onOptionsItemSelected(MenuItem item)Activity的方法中,确保在onOptionsItemSelected(MenuItem item)Fragment的方法中实现菜单项操作时返回false .

一个例子:

活动

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getSupportMenuInflater();
    inflater.inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {

        case R.id.activity_menu_item:

            // Do Activity menu item stuff here
            return true;

        case R.id.fragment_menu_item:

            // Not implemented here
            return false;
        default:
            break;
    }

    return false;
}

分段

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
    ....
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    // Do something that differs the Activity's menu here
    super.onCreateOptionsMenu(menu, inflater);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {

        case R.id.activity_menu_item:

            // Not implemented here
            return false;
        case R.id.fragment_menu_item:

            // Do Fragment menu item stuff here
            return true;

        default:
            break;
    }

    return false;
}

Answer 3

如果您发现onCreateOptionsMenu(Menu menu, MenuInflater inflater)未调用该方法,请确保从Fragment的onCreate(Bundle savedInstanceState)方法中调用以下内容:

setHasOptionsMenu(true)

Answer 4

就我而言,我需要一个菜单​​来刷新menu特定片段内部,因为我使用了:

片段:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {

    // TODO Add your menu entries here
    inflater.inflate(R.menu.menu, menu);
    super.onCreateOptionsMenu(menu, inflater);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case R.id.exit:
        System.exit(1);
        break;

    case R.id.refresh:
        webView.reload();
        break;
    }
    return true;

}

文件menu.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/exit" android:title="Exit" android:icon="@drawable/ic_action_cancel" />
    <item android:id="@+id/refresh" android:title="Refresh" android:icon="@drawable/ic_action_refresh" />
</menu>

Answer 5

在menu.xml你应该添加所有菜单项.然后,您可以隐藏在初始加载中不想看到的项目.

menu.xml文件

<item
    android:id="@+id/action_newItem"
    android:icon="@drawable/action_newItem"
    android:showAsAction="never"
    android:visible="false"
    android:title="@string/action_newItem"/>

添加setHasOptionsMenu(true)onCreate()方法以调用Fragment类中的菜单项.

FragmentClass.java

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

您不需要onCreateOptionsMenu再次在Fragment类中重写.可以通过onPrepareOptionsMenuFragment中提供的覆盖方法更改(添加/删除)菜单项.

@Override
public void onPrepareOptionsMenu(Menu menu) {
    menu.findItem(R.id.action_newItem).setVisible(true);
    super.onPrepareOptionsMenu(menu);

}

Answer 6

有一种新的方法可以做到这一点，因为androidx.activity:activity:1.4.0

您应该使用MenuProvider API。

它的使用方法如下：

您不应该调用super.setHasOptionMenu并实现，而onCreateOptionsMenu应该addMenuProvider调用onViewCreated.

一个例子：

class ExampleFragment : Fragment(R.layout.fragment_example) {

  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    // The usage of an interface lets you inject your own implementation
    val menuHost: MenuHost = requireActivity()
  
    // Add menu items without using the Fragment Menu APIs
    // Note how we can tie the MenuProvider to the viewLifecycleOwner
    // and an optional Lifecycle.State (here, RESUMED) to indicate when
    // the menu should be visible
    menuHost.addMenuProvider(object : MenuProvider {
      override fun onCreateMenu(menu: Menu, menuInflater: MenuInflater) {
        // Add menu items here
        menuInflater.inflate(R.menu.example_menu, menu)
      }

      override fun onMenuItemSelected(menuItem: MenuItem): Boolean {
        // Handle the menu selection
        return true
      }
    }, viewLifecycleOwner)
  }

来源：活动变更日志

Answer 7

TL; DR

使用android.support.v7.widget.Toolbar和只做:

toolbar.inflateMenu(R.menu.my_menu)
toolbar.setOnMenuItemClickListener {
    onOptionsItemSelected(it)
}

独立工具栏

大多数建议的解决方案setHasOptionsMenu(true)仅在父Activity在其布局中具有工具栏并通过其声明时才起作用setSupportActionBar().然后片段可以参与这个确切的ActionBar的菜单群:

Fragment.onCreateOptionsMenu():初始化Fragment主机的标准选项菜单的内容.

如果您想要一个特定片段的独立工具栏和菜单,您可以执行以下操作:

menu_custom_fragment.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
        android:id="@+id/menu_save"
        android:title="SAVE" />
</menu>

custom_fragment.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    ...

CustomFragment.kt

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    val view = inflater.inflate(layout.custom_fragment, container, false)
    val toolbar = view.findViewById<Toolbar>(R.id.toolbar)
    toolbar.inflateMenu(R.menu.menu_custom_fragment)
    toolbar.setOnMenuItemClickListener {
        onOptionsItemSelected(it)
    }
    return view
}

override fun onOptionsItemSelected(item: MenuItem): Boolean {
    return when (item.itemId) {
        R.id.menu_save -> {
            // TODO: User clicked the save button
            true
        }
        else -> super.onOptionsItemSelected(item)
    }
}

是的,就这么简单.你甚至不需要覆盖onCreate()或onCreateOptionsMenu().

PS:这只是一起工作android.support.v4.app.Fragment和android.support.v7.widget.Toolbar(也一定要使用AppCompatActivity和AppCompat主题在你的styles.xml).

Answer 8

在充气菜单之前,您需要使用menu.clear().

@Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        menu.clear();
        inflater.inflate(R.menu.menu, menu);
        super.onCreateOptionsMenu(menu, inflater);
    }

和

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);
    }

Answer 9

就我而言,这是步骤.

步骤1

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // Here notify the fragment that it should participate in options menu handling.
    setHasOptionsMenu(true);
}

第2步

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    // First clear current all the menu items
    menu.clear();

    // Add the new menu items
    inflater.inflate(R.menu.post_stuff, menu);

    super.onCreateOptionsMenu(menu, inflater);
}

步骤3

 @Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.post_stuff:
            Log.d(TAG, "Will post the photo to server");
            return true;
        case R.id.cancel_post:
            Log.d(TAG, "Will cancel post the photo");
            return true;
        default:
            break;
    }
    return super.onOptionsItemSelected(item);
}

Answer 10

如果要添加菜单自定义

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.menu_custom, menu);
}

Answer 11

我遇到了同样的问题,我的片段是ViewPager的页面.它发生的原因是我在实例化FragmentPagerAdapter时使用子片段管理器而不是活动支持片段管理器.