0
在我的Android應用程序中，我將谷歌地圖放在一個片段中，但在下面一行中得到空指針異常。我引用了許多關於支持片段空指針異常的流程鏈接，但我無法解決我的問題。Android谷歌地圖v2 - 支持片段null poiner異常
myMAPF.getMap(); // Null pointer error occurred line.
這個片段裏面執行地圖的我的全部代碼。
import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
public class MapFragment2 extends SupportMapFragment {
private GoogleMap googleMap;
// latitude and longitude
double latitude = 17.385044;
double longitude = 78.486671;
static final LatLng HAMBURG = new LatLng(53.558, 9.927);
static final LatLng KIEL = new LatLng(53.551, 9.993);
private FragmentManager myFM;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View view = inflater.inflate(R.layout.location_fragment, container,
false);
myFM = getActivity().getSupportFragmentManager();
if (googleMap == null) {
final SupportMapFragment myMAPF = (SupportMapFragment) myFM
.findFragmentById(R.id.location_map);
if (myMAPF == null) {
Log.e("myMAPF", "null");
} else {
Log.e("myMAPF", "NOT null");
}
myMAPF.getMap();
if (googleMap == null) {
Toast.makeText(getActivity().getApplicationContext(),
"Sorry! unable to create maps", Toast.LENGTH_SHORT)
.show();
}
}
return view;
}
}
XML佈局：（location_fragment.xml）定義爲
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="10dp" >
<Button
android:id="@+id/location_btn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="map button" />
<fragment
android:id="@+id/location_map"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="10dp"
class="com.google.android.gms.maps.SupportMapFragment" />
</LinearLayout>
我FragmentActivity類如下所示：
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTabHost;
.......
public class FragActivity extends FragmentActivity implements
OnTabChangeListener {
private static FragmentTabHost mTabHost;
// This activity has 3 tabs one of the tab has map
// ...............
}
Posted full Logcat:
java.lang.NullPointerException
at in.murali.pupdemo.MapFragment2.onCreateView(MapFragment2.java:44)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1786)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:947)
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.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:486)
at android.support.v4.app.FragmentTabHost.onAttachedToWindow(FragmentTabHost.java:283)
at android.view.View.dispatchAttachedToWindow(View.java:13418)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2653)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2660)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2660)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2660)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2660)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1476)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1239)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6486)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:803)
at android.view.Choreographer.doCallbacks(Choreographer.java:603)
at android.view.Choreographer.doFrame(Choreographer.java:573)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:789)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:157)
at android.app.ActivityThread.main(ActivityThread.java:5356)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
at dalvik.system.NativeStart.main(Native Method)
我的申請已在庫文件夾android-support-v4.jar和我的應用程序作爲參考如下圖所示。
我已在清單XML所有必要的權限和關鍵。
你可以在這裏看到我的SupportMap實現：http://stackoverflow.com/questions/25517170/adding-markers-in-background-while-looping-through-arraylist/ 25517475＃25517475也許它對你有用 – cYrixmorten 2015-02-07 14:30:23
我想myFM.findFragmentById（R.id.location_map）;應該是view.findFragmentById（R.id.location_map）; – Muthu 2015-02-07 14:41:54
@Muthu，如果我改變此線爲 「\t \t \t最終SupportMapFragment myMAPF =（SupportMapFragment）視圖 \t \t \t \t \t .findViewById（R.id.location_map）;」我得到了「無法從視圖投射到SupportMapFragment」。我怎麼能改變這個？ – 2015-02-07 15:31:05