フラグメント内のOsmdroid nullオブジェクト参照のITileSource

Question

osmdroidライブラリにいくつかの問題があります。 私のアプリには3つの断片のスライダーがあり、そのうちの1つにオープンストリートマップを追加しようとしていますが、この例外が常にあり、修正方法はわかりません。私はgithubサイトhttps://github.com/osmdroid/osmdroidのようにライブラリを実装しようとしました。私は通常のアクティビティを使用している場合には機能しますが、フラグメントでも機能するとうまくいくでしょう。

多くの感謝！

package ... .map; 

import android.os.Bundle; 
import android.preference.PreferenceManager; 
import android.support.v4.app.Fragment; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 

import org.osmdroid.api.IMapController; 
import org.osmdroid.config.Configuration; 
import org.osmdroid.tileprovider.tilesource.TileSourceFactory; 
import org.osmdroid.util.GeoPoint; 
import org.osmdroid.views.MapView; 

import ... .R; 

public class TabFragmentMap extends Fragment { 

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

     Configuration.getInstance().load(getContext(), PreferenceManager.getDefaultSharedPreferences(getContext())); 

     MapView map = (MapView) getActivity().findViewById(R.id.map); 
     map.setTileSource(TileSourceFactory.MAPNIK); 

     map.setBuiltInZoomControls(true); 
     map.setMultiTouchControls(true); 

     IMapController mapController = map.getController(); 
     mapController.setZoom(9); 
     GeoPoint startPoint = new GeoPoint(48.8583, 2.2944); 
     mapController.setCenter(startPoint); 

     return inflater.inflate(R.layout.tab_fragment_map, container, false); 
    } 

    @Override 
    public void onResume() { 
     super.onResume(); 
     Configuration.getInstance().load(getContext(), PreferenceManager.getDefaultSharedPreferences(getActivity())); 
    } 
} 

とレイアウトXML

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:orientation="vertical"> 

     <org.osmdroid.views.MapView 
      android:id="@+id/map" 
      android:layout_width="fill_parent" 
      android:layout_height="fill_parent" /> 

</LinearLayout> 

があるが私にこの例外をスロー：

java.lang.NullPointerException: Attempt to invoke virtual method 'void org.osmdroid.views.MapView.setTileSource(org.osmdroid.tileprovider.tilesource.ITileSource)' on a null object reference 
     at ... .map.TabFragmentMap.onCreateView(TabFragmentMap.java:46) 
     at android.support.v4.app.Fragment.performCreateView(Fragment.java:2080) 
     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1108) 
     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1290) 
     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:801) 
     at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:1638) 
     at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:679) 
     at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:166) 
     at android.support.v4.view.ViewPager.populate(ViewPager.java:1240) 
     at android.support.v4.view.ViewPager.populate(ViewPager.java:1088) 
     at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1614) 
     at android.view.View.measure(View.java:18930) 
     at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:715) 
     at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:461) 
     at android.view.View.measure(View.java:18930) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) 
     at android.widget.FrameLayout.onMeasure(FrameLayout.java:194) 
     at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135) 
     at android.view.View.measure(View.java:18930) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) 
     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1486) 
     at android.widget.LinearLayout.measureVertical(LinearLayout.java:765) 
     at android.widget.LinearLayout.onMeasure(LinearLayout.java:647) 
     at android.view.View.measure(View.java:18930) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) 
     at android.widget.FrameLayout.onMeasure(FrameLayout.java:194) 
     at android.view.View.measure(View.java:18930) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) 
     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1486) 
     at android.widget.LinearLayout.measureVertical(LinearLayout.java:765) 
     at android.widget.LinearLayout.onMeasure(LinearLayout.java:647) 
     at android.view.View.measure(View.java:18930) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5976) 
     at android.widget.FrameLayout.onMeasure(FrameLayout.java:194) 
     at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2705) 
     at android.view.View.measure(View.java:18930) 
     at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2154) 
     at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1248) 
     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1484) 
     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1139) 
     at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6238) 
     at android.view.Choreographer$CallbackRecord.run(Choreographer.java:884) 
     at android.view.Choreographer.doCallbacks(Choreographer.java:696) 
     at android.view.Choreographer.doFrame(Choreographer.java:631) 
     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:870) 
     at android.os.Handler.handleCallback(Handler.java:743) 
     at android.os.Handler.dispatchMessage(Handler.java:95) 
     at android.os.Looper.loop(Looper.java:150) 
     at android.app.ActivityThread.main(ActivityThread.java:5621) 
     at java.lang.reflect.Method.invoke(Native Method) 
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:794) 
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:684) 

Answer 1

あなたは（getActivity()を経由して）現在の活動にごMapViewインスタンスを探しています。ただし、ビューはアクティビティレイアウトに含まれず、フラグメントレイアウトに含まれます。代わりにフラグメントレイアウトで検索してみてください。

View view = inflater.inflate(R.layout.fragment_main, container, false); 
MapView map = (MapView) view.findViewById(R.id.map);