我不确定为什么它会显示为空,如果与片段、片段标题或抽屉有关,因为它在这个片段被拉起的主要活动中。
这是我的菜单xml项:
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto" >
<item android:id="@+id/action_search"
android:title="@string/action_search"
android:icon="@drawable/ic_action_search"
app:showAsAction="always"
app:actionViewClass="android.support.v7.widget.SearchView" />
</menu>
这里是代码片段:
public class BrowseFragment extends Fragment {
//action bar expands to search
//search - keyword or tab search, title
//include popular - same algorithm as home
//show categories
//category click takes you to grid activity
//adapter with custom model
private CategoryViewerAdapter adapter;
//list with custom model
private List<CategoryItem> categoriesList;
//List view
private ListView categoryListView;
//SearchView
private SearchView search;
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.browse, menu);
//find the menu item and set search view at the same time
search = (SearchView) menu.findItem(R.id.action_search).getActionView();
//to always show the search view - to include this must implement it above
search.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String s) {
return false;
}
@Override
public boolean onQueryTextChange(String s) {
return false;
}
});
search.setIconified(false);
super.onCreateOptionsMenu(menu,inflater);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_browse, container, false);
//Allows menu options in fragment
setHasOptionsMenu(true);
//Set adapter for multi-select model and adapter
adapter = new CategoryViewerAdapter(getActivity(), getSingleCategory());
categoryListView = (ListView) rootView.findViewById(R.id.categoryListView);
categoryListView.setAdapter(adapter);
return rootView;
}
//call to retrieve list
private List<CategoryItem> getSingleCategory() {
//initiate new list
categoriesList = new ArrayList<CategoryItem>();
//called to get string array
Resources res = getResources();
String[] categories = res.getStringArray(R.array.categories);
//loop through string array
for (String category : categories) {
categoriesList.add(get(category));
}
return categoriesList;
}
//call model to set names and methods for each item
private CategoryItem get(String name) {
return new CategoryItem(name);
}
}
空指针错误指向这行代码:
search.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
以下是错误日志:
03-03 02:50:33.590 15744-15744/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.app, PID: 15744
java.lang.NullPointerException
at com.example.app.BrowseFragment.onCreateOptionsMenu(BrowseFragment.java:64)
at android.app.Fragment.performCreateOptionsMenu(Fragment.java:1780)
at android.app.FragmentManagerImpl.dispatchCreateOptionsMenu(FragmentManager.java:1927)
at android.app.Activity.onCreatePanelMenu(Activity.java:2539)
at com.android.internal.policy.impl.PhoneWindow.preparePanel(PhoneWindow.java:436)
at com.android.internal.policy.impl.PhoneWindow.doInvalidatePanelMenu(PhoneWindow.java:800)
at com.android.internal.policy.impl.PhoneWindow$1.run(PhoneWindow.java:221)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
at android.view.Choreographer.doCallbacks(Choreographer.java:574)
at android.view.Choreographer.doFrame(Choreographer.java:543)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
-keep class android.support.v7.widget.SearchView { *; }
对我很有效。谢谢伙计。 - Anish Kumar