我想通过Google地方信息API在操作栏中使用搜索视图小部件,偶然发现了指向Stack Overflow各个帖子*享的教程的链接,因此我决定进行检查.我已经将其全部实现到现有代码中,但是我遇到了NullPointerException并希望有人可以帮助我,以便我可以调试问题.我一直在浏览Stack Overflow上的各种帖子以及Google上的文章…

Logcat指定它是由第119和123行引起的.

MainActivity.java：

public class MainActivity extends FragmentActivity implements
GooglePlayServicesClient.ConnectionCallbacks,
GooglePlayServicesClient.OnConnectionFailedListener,
LocationListener,
OnMapLongClickListener,
LoaderCallbacks<Cursor> {

//Global Constants
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;

// Milliseconds per second
private static final int MILLISECONDS_PER_SECOND = 1000;
// Update frequency in seconds
public static final int UPDATE_INTERVAL_IN_SECONDS = 5;
// Update frequency in milliseconds
private static final long UPDATE_INTERVAL =
        MILLISECONDS_PER_SECOND * UPDATE_INTERVAL_IN_SECONDS;
// The fastest update frequency, in seconds
private static final int FASTEST_INTERVAL_IN_SECONDS = 1;
// A fast frequency ceiling in milliseconds
private static final long FASTEST_INTERVAL =
        MILLISECONDS_PER_SECOND * FASTEST_INTERVAL_IN_SECONDS;


//Global Variables
GoogleMap map;
Marker marker;
LocationRequest requestLocation;
LocationClient locationClient;
LocationManager locationManager;
boolean updatesRequested;
Geofence geoFence;
Vibrator vibStatus;


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

    // Create the LocationRequest object
    requestLocation = LocationRequest.create();
    // Use high accuracy
    requestLocation.setPriority(
            LocationRequest.PRIORITY_HIGH_ACCURACY);
    // Set the update interval to 5 seconds
    requestLocation.setInterval(UPDATE_INTERVAL);
    // Set the fastest update interval to 1 second
    requestLocation.setFastestInterval(FASTEST_INTERVAL);


    SupportMapFragment fragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
    map = fragment.getMap();

    //Enables "My Location" button on map fragment
    map.getUiSettings().setMyLocationButtonEnabled(true);

    //Create a new location client, using the enclosing class to handle callbacks.
    locationClient = new LocationClient(this, this, this);
    // Start with updates turned off
    updatesRequested = false;

    //
    map.setOnMapLongClickListener(this);

    // Look up the AdView as a resource and load a request.
    AdView adView = (AdView)this.findViewById(R.id.adView);
    AdRequest adRequest = new AdRequest.Builder().build();
    adView.loadAd(adRequest);

    handleIntent(getIntent()); //This is line 119 in my code
  }

private void handleIntent(Intent intent){
    if(intent.getAction().equals(Intent.ACTION_SEARCH)){ //This is line 123 in my code
        doSearch(intent.getStringExtra(SearchManager.QUERY));
    }else if(intent.getAction().equals(Intent.ACTION_VIEW)){
        getPlace(intent.getStringExtra(SearchManager.EXTRA_DATA_KEY));
    }
}

@Override
protected void onNewIntent(Intent intent) {
    super.onNewIntent(intent);
    setIntent(intent);
    handleIntent(intent);
}
...
}

AndroidManifest.xml：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com...." //Removed while posting on forum
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="10"
    android:targetSdkVersion="19" />

<!-- Protect the map component of the application using application signature -->
<permission
    android:name="com.....permission.MAPS_RECEIVE" //Removed while posting on forum
    android:protectionLevel="signature" />

<!-- Allows to receive map -->
<uses-permission android:name="com.....permission.MAPS_RECEIVE" /> //Removed while posting on forum

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.VIBRATE" />

<uses-feature
    android:glEsVersion="0x00020000"
    android:required="true" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/Theme.AppCompat.Light.DarkActionBar" >
    <activity
        android:name="com.....SplashActivity" //Removed while posting on forum
        android:label="@string/app_name"
        android:screenOrientation="portrait" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name="com.....MainActivity" //Removed while posting on forum
        android:label="@string/app_name"
        android:launchMode="singleTop"
        android:screenOrientation="portrait" >
        <intent-filter>
            <action android:name="android.intent.action.SEARCH" />
        </intent-filter>
        <!-- Points to searchable activity -->
        <meta-data android:name="android.app.default_searchable"
            android:value="com.....MainActivity" /> //Removed while posting on forum

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

    <activity
        android:name="com.....PreferencesActivity" //Removed while posting on forum
        android:label="@string/title_activity_settings"
        android:parentActivityName="com.....MainActivity" //Removed while posting on forum
        android:screenOrientation="portrait" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.....MainActivity" /> //Removed while posting on forum
    </activity>
    <activity
        android:name="com.....AlarmActivity" //Removed while posting on forum
        android:label="@string/title_activity_alarm" >
    </activity>
    <activity
        android:name="com.google.android.gms.ads.AdActivity"
        android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize" />
    <activity
        android:name="com.....PlaceJSONParser" //Removed while posting on forum
        android:label="@string/title_activity_place_jsonparser" >
    </activity>
    <activity
        android:name="com.....PlaceDetailsJSONParser" //Removed while posting on forum
        android:label="@string/title_activity_place_details_jsonparser" >
    </activity>
    <activity
        android:name="com.....PlaceProvider" //Removed while posting on forum
        android:label="@string/title_activity_place_provider" >
    </activity>

     <provider
        android:name=".PlaceProvider"
        android:authorities="com.....PlaceProvider" //Removed while posting on forum
        android:exported="false" />

    <meta-data
        android:name="com.google.android.gms.version"
        android:value="@integer/google_play_services_version" />
    <meta-data
        android:name="com.google.android.maps.v2.API_KEY"
        android:value="MY-KEY-HERE" /> //Removed while posting on forum

</application>

</manifest>

解决方法:

您是从SplashActivity启动MainActivity吗？搜索视图中什么时候发生？看起来像它.调用startActivity(intent)时,需要确保已为该意图添加了一个操作：

Intent mainActivityIntent = new Intent(context);
mainActivityIntent.setAction(Intent.ACTION_SEARCH);
startActivity(mainActivityIntent);

如果您(或使用意图调用您的MainActivity的任何对象)未对该意图设置操作,则当您尝试对Activity中的调用意图进行getAction()时,您将获得一个空指针.