SearchView 出现空指针异常答案

【问题标题】：nullpointerexception with SearchViewSearchView 出现空指针异常
【发布时间】：2015-07-25 12:54:41
【问题描述】：

较旧的 API 15 和 16 没有此错误，但由于某种原因，新的 API 19 在 SearchView.setOnQueryTextListener(this) 处抛出了 NullPointerException。
我可以通过将侦听器移动到 onCreateOptionsMenu 来修复它，但是当我将它移回onCreateView时，它在旧设备上不起作用，反之亦然。

public class EventFragment extends Fragment implements AdapterView.OnItemClickListener, SearchView.OnQueryTextListener, View.OnClickListener
{
    private List<EventItem> items;
    private ProgressBar progressBar;
    private View view;
    private JazzyListView listView;
    static EventAdapter adapter;
    SearchView searchView;

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

        // creates call to
        // onPrepareOptionsMenu()
    }

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

           MenuItem searchItem=  menu.findItem(R.id.search);
                searchView =
                    (SearchView) MenuItemCompat.getActionView(searchItem);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        if (view == null) {
            //inflate the layout for the items in view
            view = inflater.inflate(R.layout.fragment_layout, container, false);
            progressBar = (ProgressBar) view.findViewById(R.id.progressBar);
            listView = (JazzyListView) view.findViewById(R.id.listView);

            Button button = (Button) view.findViewById(R.id.button3);
            //Customize listView/searchview
            listView.setTextFilterEnabled(true);
            listView.setOnItemClickListener(this);
            listView.setSmoothScrollbarEnabled(true);
            searchView.setOnQueryTextListener(this);
            button.setOnClickListener(this);
            startService();
        } else {
            // If we are returning from a configuration change:
            //  remove view and re-attach it to the current configuration
            ViewGroup parent = (ViewGroup) view.getParent();
            parent.removeView(view);
        }

        return view;
    }

    @Override
    public boolean onQueryTextChange(String newText) {
        adapter.getFilter().filter(newText);
        return false;
    }

这里是菜单：

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item android:id="@+id/search"
    android:title="@string/hello"
    android:icon="@drawable/search"
    android:showAsAction="collapseActionView|always"
    android:actionViewClass="android.widget.SearchView"
  />

</menu>

这里是日志：

 05-13 16:33:34.146  10646-10646/com.parse.starter E/CrashReporting﹕ ParseCrashReporting caught a RuntimeException exception for com.parse.starter. Building report.
05-13 16:33:34.169  10646-10646/com.parse.starter E/CrashReporting﹕ Handling exception for crash
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.parse.starter/com.parse.starter.EventKGHS}: java.lang.NullPointerException
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2035)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2060)
        at android.app.ActivityThread.access$600(ActivityThread.java:127)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1181)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:4558)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
        at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.NullPointerException
        at com.parse.starter.EventFragment.onQueryTextChange(EventFragment.java:160)
        at android.widget.SearchView.onTextChanged(SearchView.java:1091)
        at android.widget.SearchView.access$2000(SearchView.java:90)
        at android.widget.SearchView$11.onTextChanged(SearchView.java:1550)
        at android.widget.TextView.sendOnTextChanged(TextView.java:7692)
        at android.widget.TextView.setText(TextView.java:3365)
        at android.widget.TextView.setText(TextView.java:3218)
        at android.widget.EditText.setText(EditText.java:78)
        at android.widget.TextView.setText(TextView.java:3193)
        at android.widget.TextView.onRestoreInstanceState(TextView.java:3093)
        at android.view.View.dispatchRestoreInstanceState(View.java:9968)
        at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2324)
        at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2324)
        at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2324)
        at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2324)
        at android.view.View.restoreHierarchyState(View.java:9946)
        at com.android.internal.view.menu.MenuBuilder.restoreActionViewStates(MenuBuilder.java:358)
        at com.android.internal.policy.impl.PhoneWindow.preparePanel(PhoneWindow.java:429)
        at com.android.internal.policy.impl.PhoneWindow.invalidatePanelMenu(PhoneWindow.java:890)
        at android.app.Activity.invalidateOptionsMenu(Activity.java:2671)
        at com.parse.starter.EventFragment.onCreate(EventFragment.java:57)
        at android.support.v4.app.Fragment.performCreate(Fragment.java:1763)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:913)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
        at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
        at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
        at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:548)
        at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1133)
        at android.app.Activity.performStart(Activity.java:4646)
.......

从缺乏输入和结果来看。我一定发现了一个错误！我会尽快报告。

更新：如果我使用其他东西而不是将 onquerylistener 设置为“this”怎么办？

【问题讨论】：

你也可以发布你的异常堆栈吗？
如果我把它移到 onCreate 会怎样？
好的，我再次将其移至 onCreate，它仅适用于旧设备
在调用findViewById()之前需要先给菜单充气
哦，是的，我知道。充气它会创建两个相同的项目，因为我已经在另一个类中充气了它。另外，我在它收到异常时给它充气了，但它没有帮助。

标签： java android nullpointerexception android-actionbar searchview

【解决方案1】：

**尝试在您实例化 EventFragment 的活动中监听 searchView **

【讨论】：

【解决方案2】：

好的，我已经纠正了这个问题。我做了三件事，我不确定是哪一件修复了它，或者是否全部修复了，但这不是重点。首先，我为要设置的 SearchView 侦听器创建了一个私有 OnQueryTextListener 类。然后我将 SearchView OnQueryTextListener 移动到 onCreateOptionsMenu。最后，如果我必须选择一个，这是假设修复它的一个，我删除了 getActivity().invalidateOptionsMenu();线。我可能仍然会提交错误报告，因为这真的不应该首先发生。在下面的评论中留下您对为什么会发生这种情况的解释或编辑我的答案。

【讨论】：