嵌套的SupportMapFragment

Question

在添加支持映射片段时，我遇到了以下异常

05-22 23:51:12.817: E/AndroidRuntime(4515): java.lang.NullPointerException
05-22 23:51:12.817: E/AndroidRuntime(4515):     at kbh.a(Unknown Source)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at mbi.a(Unknown Source)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at lxn.a(Unknown Source)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at lxm.a(Unknown Source)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at fnb.onTransact(SourceFile:107)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.os.Binder.transact(Binder.java:361)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at com.google.android.gms.maps.internal.IMapFragmentDelegate$a$a.onCreateView(Unknown Source)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at com.google.android.gms.maps.SupportMapFragment$a.onCreateView(Unknown Source)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at com.google.android.gms.dynamic.a$4.b(Unknown Source)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at com.google.android.gms.dynamic.a.a(Unknown Source)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at com.google.android.gms.dynamic.a.onCreateView(Unknown Source)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at com.google.android.gms.maps.SupportMapFragment.onCreateView(Unknown Source)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.Fragment.performCreateView(Fragment.java:1500)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.Fragment.performResume(Fragment.java:1550)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:963)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.os.Handler.handleCallback(Handler.java:733)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.os.Handler.dispatchMessage(Handler.java:95)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.os.Looper.loop(Looper.java:136)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at android.app.ActivityThread.main(ActivityThread.java:5102)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at java.lang.reflect.Method.invokeNative(Native Method)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at java.lang.reflect.Method.invoke(Method.java:515)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
05-22 23:51:12.817: E/AndroidRuntime(4515):     at dalvik.system.NativeStart.main(Native Method)

这在App上是随机发生的。它正常工作一次，两次甚至三次，然后就崩溃了。有时地图会出现，但随后就会崩溃。

非常感谢

Answer 1

看起来，你不能有一个嵌套的有SupportMapFragment的片段。

我所做的如下所示：

MainFragment extends Fragment;
FirstChildFragment extends Fragment;
MapFragment extends Fragment;

MainFragment，它是主要的片段，它将包含要显示的子片段。FirstChildFragment是另一个片段，它被保存在MainFragment中，最后MapFragment被保存在FirstChildFragment中，MapFragment使SupportMapFragment膨胀，有时它可以工作。我把SupportMapFragment的MapFragment改成了extend，它起作用了……

也许我对片段的抽象是不正确的。但我确实在很多情况下使用了片段，它保持了一些视图逻辑的封装。

谢谢&对不起。