GetSupportFragmentManager总是返回null

我正在研究一个小型的android应用程序，每当我打电话给GoogleMap map = ((SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map)).getMap()时，它总是返回null。我试图在带有Google Play的API 17的设备上运行此应用。GetSupportFragmentManager总是返回null

MapActivity：

public class MapActivity extends FragmentActivity implements LocationSource, LocationListener { 

    private static final String TAG = "MapActivity"; 
    private String device = android.os.Build.MODEL; 

    private static final String UPDATE_LOC_URL = "http://lab.uzlabina.cz/~vongrad/Tracker/update_loc.php"; 
    private static final String LOAD_LOCATIONS = "http://lab.uzlabina.cz/~vongrad/Tracker/load_locations.php"; 
    private static final int ADD_MAP_PIN = 1; 

    private Controller controller; 

    private LocationManager locationManager; 
    private OnLocationChangedListener locListener; 


    private GoogleMap map; 

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

     controller = Controller.getInstance(new User()); 
     controller.setUserName(device); 

     locationManager = (LocationManager)getSystemService(LOCATION_SERVICE); 

     if (locationManager != null){ 
      boolean isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER); 
      boolean isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER); 
      Log.d(TAG, "GPS " + isGPSEnabled + "Net " + isNetworkEnabled); 

      if (isGPSEnabled){ 
       locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 50L, 1F, this); 
      } 
      else if (isNetworkEnabled){ 
       locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 500L, 10F, this); 
      } 
      else{ 
       Toast.makeText(this, "GPS is disabled", Toast.LENGTH_LONG); 
      } 
     } 
     else 
     { 
      Toast.makeText(this, "Something went wrrong", Toast.LENGTH_LONG); 
     } 
     setUpMapIfNeeded(); 




    } 
    public void onResume(){ 
     //updateLocation.start(); 
     super.onResume(); 
     //setUpMapIfNeeded(); 

     if (locationManager != null){ 
      map.setMyLocationEnabled(true); 
     } 
    } 

    public void onPause(){ 
     //loadFriendsLocations.stop(); 
     if (locationManager != null){ 
      locationManager.removeUpdates(this); 
     } 
     super.onPause(); 
    } 


    private void setUpMapIfNeeded() { 
     if (map == null){ 

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

      if (map != null){ 
       setUpMap(); 
      } 
     } 
    } 


    private void setUpMap() { 
     map.setMyLocationEnabled(true); 
     loadFriendsLocations.start(); 
    }

布局：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    tools:context=".MapActivity" > 

    <TextView 
     android:id="@+id/header" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/hello_world" /> 

    <fragment 
     android:id="@+id/map" 
     android:name="com.google.android.gms.maps.SupportMapFragment" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     /> 


</RelativeLayout>

清单：

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="cz.vongrad.locator" 
    android:versionCode="1" 
    android:versionName="1.0" > 

    <uses-sdk 
     android:minSdkVersion="11" 
     android:targetSdkVersion="17" /> 

    <permission 
     android:name="cz.vongrad.locator.permission.MAPS_RECEIVE" 
     android:protectionLevel="signature"/> 
    <uses-permission android:name="cz.vongrad.locator.permission.MAPS_RECEIVE"/> 


    <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"/> 
    <!-- The following two permissions are not required to use 
    Google Maps Android API v2, but are recommended. --> 
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/> 
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/> 

    <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/AppTheme" android:debuggable="true"> 

     <meta-data 
      android:name="com.google.android.maps.v2.API_KEY" 
      android:value="blabla"/> 

     <activity 
      android:name="cz.vongrad.locator.MapActivity" 
      android:label="@string/app_name" > 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

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

</manifest>

logcat的：

10-05 19:40:13.284: E/AndroidRuntime(2697): FATAL EXCEPTION: main 
10-05 19:40:13.284: E/AndroidRuntime(2697): java.lang.RuntimeException: Unable to start activity ComponentInfo{cz.vongrad.locator/cz.vongrad.locator.MapActivity}: java.lang.NullPointerException 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at android.app.ActivityThread.access$600(ActivityThread.java:141) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at android.os.Handler.dispatchMessage(Handler.java:99) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at android.os.Looper.loop(Looper.java:137) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at android.app.ActivityThread.main(ActivityThread.java:5041) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at java.lang.reflect.Method.invokeNative(Native Method) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at java.lang.reflect.Method.invoke(Method.java:511) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at dalvik.system.NativeStart.main(Native Method) 
10-05 19:40:13.284: E/AndroidRuntime(2697): Caused by: java.lang.NullPointerException 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at cz.vongrad.locator.MapActivity.setUpMapIfNeeded(MapActivity.java:115) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at cz.vongrad.locator.MapActivity.onCreate(MapActivity.java:86) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at android.app.Activity.performCreate(Activity.java:5104) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 
10-05 19:40:13.284: E/AndroidRuntime(2697):  ... 11 more

我希望有任何建议。在此先感谢！

来源

2013-10-05 Husky

您可以发布清单 – Raghunandan

检查设备位置服务..这两个选项都应该标记为勾号。 1）使用无线网络和2）位置和谷歌 – shujatAli

我做到了，一切都打开了......可能问题是Google Play服务已过期？ – Husky

尝试早期调用这个setUpMapIfNeeded（）几行..初始化的LocationManager

setContentView(R.layout.activity_main); 

     controller = Controller.getInstance(new User()); 
     controller.setUserName(device); 

setUpMapIfNeeded();

来源

2013-10-05 18:09:50 shujatAli

你没有看到崩溃日志，崩溃发生在那里。 –

显示导入文件。你做了.. public class MapActivity extends FragmentActivity implements LocationSource，LocationListener { 我想你可能已经导入了错误的库文件..请显示。 – shujatAli

我用getChildFragmentManager（前），而不是getSupportFragmentManager（）和它的工作

来源

2015-08-24 23:44:22

GetSupportFragmentManager总是返回null

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