我试图从一组片段中添加一个项目到选项菜单。
我已经创建了一个新的MenuFragment类,并扩展了我希望包含菜单项的片段。代码如下:
Java:
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);
}
}
科特林:
class MenuFragment : Fragment {
lateinit var fav: MenuItem
override fun onCreate(savedInstanceState: Bundle) {
super.onCreate(savedInstanceState)
setHasOptionsMenu(true)
}
override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
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。
在我的例子中,下面是步骤。
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);
}
步骤2
@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);
}
设置setHasMenuOptions(true)工作,如果应用程序有一个主题与动作栏,如theme . materialcomponents . daynight . darkactionbar或Activity有它自己的工具栏,否则oncreateoptionmenufragment不会被调用。
如果你想使用独立的工具栏,你要么需要获得活动,并将工具栏设置为支持操作栏
(requireActivity() as? MainActivity)?.setSupportActionBar(toolbar)
它让你的fragment onCreateOptionsMenu被调用。
其他的选择是,你可以用Toolbar . inflatemmenu (r.m menu. your_menu)和项目监听器来膨胀你的工具栏自己的菜单
toolbar.setOnMenuItemClickListener {
// do something
true
}
除此之外,我还要补充一件事,以及它不适合我的原因。
这与Napster的答案相似。
Make sure your fragment's hosting activity extends AppCompatActivity, not FragmentActivity!
public class MainActivity extends AppCompatActivity {
}
From the Google Reference Documentation for FragmentActivity:
Note: If you want to implement an activity that includes an action bar, you should instead use the ActionBarActivity class, which is a subclass of this one, so allows you to use Fragment APIs on API level 7 and higher.
To update Napster's answer -- ActionBarActivity now being deprecated, use AppCompatActivity instead.
When using AppCompatActivity, also make sure you set "the activity theme toTheme.AppCompat or a similar theme" (Google Doc).
注意:android.support.v7.app。AppCompatActivity是android.support.v4.app的子类。FragmentActivity类(参见AppCompatActivity ref doc)。
现在在2022年,谷歌已弃用setHasOptionsMenu,你应该使用MenuProvider代替。根据我的经验,当我使用setHasOptionsMenu方法时,我在一些android 11、12上得到了NoSuchMethodException。
当使用MenuProvider为您的活动提供菜单时,不再需要此方法,它取代了onCreateOptionsMenu作为推荐的方式来提供一致的、可选的生命周期感知的、模块化的方式来处理菜单创建和项目选择。
这是你如何添加菜单到你的活动/片段atm:
/**
* Using the addMenuProvider() API directly in your Activity
**/
class ExampleActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
// Add menu items without overriding methods in the Activity
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
}
})
}
}
/**
* Using the addMenuProvider() API in a Fragment
**/
class ExampleFragment : Fragment() {
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, Lifecycle.State.RESUMED)
}
这是参考链接。
啊,对于像我这样懒惰的人,你必须加上这个:
dependencies {
val activity_version = "1.5.1"
// Java language implementation
implementation("androidx.activity:activity:$activity_version")
// Kotlin
implementation("androidx.activity:activity-ktx:$activity_version")
}
我也遇到了同样的问题,但我认为最好总结并介绍让它工作的最后一步:
在Fragment的onCreate(Bundle savedInstanceState)方法中添加sethasoptionmenu (true)方法。
重写onCreateOptionsMenu(菜单菜单,MenuInflater膨胀器)(如果你想做一些不同的在你的片段的菜单)和onOptionsItemSelected(MenuItem项目)方法在你的片段。
在onOptionsItemSelected(MenuItem item) Activity的方法中,当菜单项操作将在onOptionsItemSelected(MenuItem item) Fragment的方法中实现时,确保返回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;
}
片段
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;
}