Android 尝试从fragmentManager获取映射时始终返回null

我正在尝试做一个使用ViewPager的android应用程序。在第三页中，我在片段的xml中实例化了一个映射：

<?xml version="1.0" encoding="utf-8"?>
<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"
tools:context=".MainActivity"
android:orientation="vertical">

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

</RelativeLayout>

Debuggin我发现FragmentManager正确地包含了ViewPager的五个片段，但其中的地图片段不在那里

你知道我怎样才能正确地得到地图吗？多谢各位

编辑 我忘了说我膨胀了fragment类中onCreate（）中包含映射的片段：

public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_mapa, container, false);

运行后获得的logcat错误是下一个错误：

05-18 20:41:29.725: E/AndroidRuntime(20636): FATAL EXCEPTION: main
05-18 20:41:29.725: E/AndroidRuntime(20636): Process: com.example.app, PID: 20636
05-18 20:41:29.725: E/AndroidRuntime(20636): java.lang.NullPointerException
05-18 20:41:29.725: E/AndroidRuntime(20636):    at fragments.MapaTab.inicialitzarMapa(MapaTab.java:113)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at fragments.MapaTab.inicialitzarLoc(MapaTab.java:108)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at fragments.MapaTab.onActivityCreated(MapaTab.java:90)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:892)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1083)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:635)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1431)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:431)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.view.ViewPager.populate(ViewPager.java:895)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:469)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:441)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:422)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.example.app.MainActivity.onTabSelected(MainActivity.java:136)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.android.internal.app.ActionBarImpl.selectTab(ActionBarImpl.java:577)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.android.internal.app.ActionBarImpl$TabImpl.select(ActionBarImpl.java:1105)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.android.internal.widget.ScrollingTabContainerView$TabClickListener.onClick(ScrollingTabContainerView.java:547)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.view.View.performClick(View.java:4438)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.view.View$PerformClick.run(View.java:18422)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.os.Handler.handleCallback(Handler.java:733)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.os.Handler.dispatchMessage(Handler.java:95)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.os.Looper.loop(Looper.java:136)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.app.ActivityThread.main(ActivityThread.java:5017)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at java.lang.reflect.Method.invokeNative(Native Method)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at java.lang.reflect.Method.invoke(Method.java:515)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at dalvik.system.NativeStart.main(Native Method)

---

是否在onCreate中设置活动的内容视图？如果没有，则不会添加片段，因此您的片段管理器无法获取该片段，因此mapFragment将==Null请显示实际的logcat stacktrace，并指出它在代码中引用的任何行。我在onCreate（）方法中放大了内容视图，现在我编辑了这个问题，你可以看到logcat了。你可以发布完整的堆栈跟踪吗？对不起，现在你可以在logcat中看到完整的错误了

05-18 20:41:29.725: E/AndroidRuntime(20636): FATAL EXCEPTION: main
05-18 20:41:29.725: E/AndroidRuntime(20636): Process: com.example.app, PID: 20636
05-18 20:41:29.725: E/AndroidRuntime(20636): java.lang.NullPointerException
05-18 20:41:29.725: E/AndroidRuntime(20636):    at fragments.MapaTab.inicialitzarMapa(MapaTab.java:113)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at fragments.MapaTab.inicialitzarLoc(MapaTab.java:108)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at fragments.MapaTab.onActivityCreated(MapaTab.java:90)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:892)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1083)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:635)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1431)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:431)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.view.ViewPager.populate(ViewPager.java:895)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:469)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:441)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:422)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.example.app.MainActivity.onTabSelected(MainActivity.java:136)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.android.internal.app.ActionBarImpl.selectTab(ActionBarImpl.java:577)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.android.internal.app.ActionBarImpl$TabImpl.select(ActionBarImpl.java:1105)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.android.internal.widget.ScrollingTabContainerView$TabClickListener.onClick(ScrollingTabContainerView.java:547)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.view.View.performClick(View.java:4438)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.view.View$PerformClick.run(View.java:18422)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.os.Handler.handleCallback(Handler.java:733)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.os.Handler.dispatchMessage(Handler.java:95)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.os.Looper.loop(Looper.java:136)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at android.app.ActivityThread.main(ActivityThread.java:5017)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at java.lang.reflect.Method.invokeNative(Native Method)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at java.lang.reflect.Method.invoke(Method.java:515)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-18 20:41:29.725: E/AndroidRuntime(20636):    at dalvik.system.NativeStart.main(Native Method)