android - SearchView AppCompatActivity 中的空指针？

Question

我只是一个初学者，我在这里搜索了这个问题，发现了 4-5 个问题，但这对我没有帮助。我只是在 Actionbar 中尝试 searchView，我的 Activity 是 AppCompatActivity，我的代码在下面。我在这个 Activity 中使用工具栏。并使用这个 library也。 创建选项菜单:

 @Override
public boolean onCreateOptionsMenu(Menu menu) {

    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu_main, menu);
    SearchManager SManager =  (SearchManager) getSystemService(Context.SEARCH_SERVICE);
    MenuItem searchMenuItem = menu.findItem(R.id.action_search);
    SearchView searchViewAction = (SearchView) MenuItemCompat.getActionView(searchMenuItem);
    searchViewAction.setSearchableInfo(SManager.getSearchableInfo(getComponentName()));
    searchViewAction.setIconifiedByDefault(false);

    return super.onCreateOptionsMenu(menu);
}

XML:

<item android:id="@+id/action_search"
    android:title="action_search"
    MainActivity:showAsAction="ifRoom"
    MainActivity:actionViewClass="android.support.v7.widget.SearchView" />

和 logcat:

java.lang.NullPointerException
        at algonation.com.spm.MainActivity.onCreateOptionsMenu(MainActivity.java:183)
        at android.app.Activity.onCreatePanelMenu(Activity.java:2571)
        at android.support.v4.app.FragmentActivity.onCreatePanelMenu(FragmentActivity.java:277)
        at android.support.v7.internal.view.WindowCallbackWrapper.onCreatePanelMenu(WindowCallbackWrapper.java:84)
        at android.support.v7.app.AppCompatDelegateImplBase$AppCompatWindowCallback.onCreatePanelMenu(AppCompatDelegateImplBase.java:251)
        at android.support.v7.internal.view.WindowCallbackWrapper.onCreatePanelMenu(WindowCallbackWrapper.java:84)
        at android.support.v7.internal.app.ToolbarActionBar.populateOptionsMenu(ToolbarActionBar.java:449)
        at android.support.v7.internal.app.ToolbarActionBar$1.run(ToolbarActionBar.java:66)
        at android.os.Handler.handleCallback(Handler.java:808)
        at android.os.Handler.dispatchMessage(Handler.java:103)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:5292)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
        at dalvik.system.NativeStart.main(Native Method)

如果您需要 MainActivity 的完整代码，请告诉我。 非常感谢。

Answer 1

您将收到 NullPointerException，因为下行返回 null。

SManager.getSearchableInfo(getComponentName()

你需要

1 - Declare the activity(which needs to perform search) to accept the ACTION_SEARCH intent, in an <intent-filter> element.

2 - Specify the searchable configuration to use, in a <meta-data> element.

假设您在您的 MainActivity(您想要的 AppCompatActivity)中执行搜索，请参见下面的示例:

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_my_main);
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.my_main, menu);

    MenuItem searchMenuItem = menu.findItem(R.id.action_search);
    SearchView searchViewAction = (SearchView) MenuItemCompat
            .getActionView(searchMenuItem);

    // Get the SearchView and set the searchable configuration
    SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
    SearchableInfo searchableInfo = searchManager 
            .getSearchableInfo(getComponentName());
    searchViewAction.setSearchableInfo(searchableInfo);
    searchViewAction.setIconifiedByDefault(false);

    return true;

}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}
}

AndroidManifest.xml

 <application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>

          <intent-filter>
             <action android:name="android.intent.action.SEARCH" />
          </intent-filter>

          <meta-data
               android:name="android.app.searchable"
               android:resource="@xml/searchable" />

    </activity>

</application>

menu/activity_main.xml

<item
    android:id="@+id/action_search"
    app:actionViewClass="android.support.v7.widget.SearchView"
    app:showAsAction="ifRoom"
    android:title="@string/action_search"/>

res/xml/searchable.xml

<?xml version="1.0" encoding="utf-8"?>
<searchable xmlns:android="http://schemas.android.com/apk/res/android"
    android:label="@string/app_label"
    android:hint="@string/search_hint" >
</searchable>

希望能解决您的问题，供引用see here .