我在我的片段中使用搜索管理器。不幸的是，使用方法调用getActivity（）.getSystemService（context.search_service）偶尔会抛出一个nullPointerException。这种情况既发生在装有仪器的浓缩咖啡单元测试中，也发生在正常使用过程中。当我再次运行测试时，一切都很好。你能告诉我怎么解决这个问题吗？谢谢。
Stacktrace：
06-05 16:10:59.162 19183 19183 D AndroidRuntime: Shutting down VM
06-05 16:10:59.188 19183 19183 E AndroidRuntime: FATAL EXCEPTION: main
06-05 16:10:59.188 19183 19183 E AndroidRuntime: Process: foo.bar.baz, PID: 19183
06-05 16:10:59.188 19183 19183 E AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.app.Activity.getSystemService(java.lang.String)' on a null object reference
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at foo.bar.baz.sign_browser.SignBrowserFragment.onCreateOptionsMenu(SignBrowserFragment.java:139)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.app.Fragment.performCreateOptionsMenu(Fragment.java:2133)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.app.FragmentManagerImpl.dispatchCreateOptionsMenu(FragmentManager.java:1945)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.app.Activity.onCreatePanelMenu(Activity.java:2834)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.support.v4.app.FragmentActivity.onCreatePanelMenu(FragmentActivity.java:298)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.support.v7.view.WindowCallbackWrapper.onCreatePanelMenu(WindowCallbackWrapper.java:85)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.support.v7.app.AppCompatDelegateImplBase$AppCompatWindowCallbackBase.onCreatePanelMenu(AppCompatDelegateImplBase.java:241)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.support.v7.view.WindowCallbackWrapper.onCreatePanelMenu(WindowCallbackWrapper.java:85)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.support.v7.app.ToolbarActionBar.populateOptionsMenu(ToolbarActionBar.java:443)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.support.v7.app.ToolbarActionBar$1.run(ToolbarActionBar.java:60)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.os.Handler.handleCallback(Handler.java:739)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:95)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.os.Looper.loop(Looper.java:135)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5343)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:372)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905)
06-05 16:10:59.188 19183 19183 E AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:700)
06-05 16:10:59.227 835 1557 I WindowManager: Screen frozen for +393ms due to AppWindowToken{19c5842b token=Token{34cb447a ActivityRecord{10afa8a5 u0 foo.bar.baz/.activities.MainActivity t4133}}}
06-05 16:10:59.233 835 1557 W ActivityManager: Force finishing activity 1 foo.bar.baz/.activities.MainActivity
SignBrowserFragment.onCreateOptions菜单（）
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
Log.d(TAG, "onCreateOptionsMenu " + hashCode());
inflater.inflate(R.menu.options_sign_browser, menu);
final MenuItem item = menu.findItem(R.id.action_toggle_starred);
if (this.showStarredOnly) {
item.setIcon(R.drawable.ic_sign_browser_grade_checked);
} else {
item.setIcon(R.drawable.ic_sign_browser_grade);
}
final SearchManager searchManager = (SearchManager) getActivity().getSystemService(Context.SEARCH_SERVICE);
final MenuItem searchItem = menu.findItem(R.id.action_search);
final SearchView searchView = (SearchView) MenuItemCompat.getActionView(searchItem);
searchView.setSearchableInfo(searchManager.getSearchableInfo(getActivity().getComponentName()));
}
我正在使用signBrowserFragment，它包含在mainActivity中，为搜索添加选项菜单项。实际搜索在单独的signsearch活动中执行。
清单文件：
<activity
android:name=".activities.MainActivity"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<meta-data
android:name="android.app.default_searchable"
android:value=".sign_browser.search.SignSearchActivity" />
</activity>
<activity
android:name=".sign_browser.search.SignSearchActivity"
android:parentActivityName=".activities.MainActivity"
tools:ignore="UnusedAttribute">
<intent-filter>
<action android:name="android.intent.action.SEARCH" />
</intent-filter>
<meta-data
android:name="android.app.searchable"
android:resource="@xml/searchable" />
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value=".activities.MainActivity" />
</activity>
如果你需要进一步的信息，请告诉我。
编辑：为什么这被标记为“如何修复nullpointerexception”的副本？这与将其标记为“如何修复错误”的副本一样合理。：（
编辑2：抱歉，伙计们。我刚刚意识到我在createoptions菜单上发布了错误的方法代码。我的代码片段来自SignSearchActivity。唯一真正的区别是在片段中，getActivity（）在调用getSystemService之前被调用。因此getActivty（）返回空值。为什么这种情况经常发生在片段的onCreateOptionsMenu（）方法中？
最佳答案
您忘记调用super.onCreateOptions菜单（…）
@重写public void oncreateoptions菜单（菜单菜单，menuinflaterinflater）{
Log.d(TAG, "onCreateOptionsMenu " + hashCode());
super.onCreateOptionsMenu(menu, inflater);
inflater.inflate(R.menu.options_sign_browser, menu);
final MenuItem item = menu.findItem(R.id.action_toggle_starred);
if (this.showStarredOnly) {
item.setIcon(R.drawable.ic_sign_browser_grade_checked);
} else {
item.setIcon(R.drawable.ic_sign_browser_grade);
}
final SearchManager searchManager = (SearchManager) getActivity().getSystemService(Context.SEARCH_SERVICE);
final MenuItem searchItem = menu.findItem(R.id.action_search);
final SearchView searchView = (SearchView) MenuItemCompat.getActionView(searchItem);
searchView.setSearchableInfo(searchManager.getSearchableInfo(getActivity().getComponentName()));
}