我想展现一个片段内的图形页面（使用砍死兼容性库）。下面在过去的工作就好了：

I'm trying to show a MapView inside a fragment (using the hacked compatibility library). The following has worked just fine in the past:

段的 onCreateView（）只返回一个新的的FrameLayout 段的 onActivityCreated（）获得来自活性的研究的MapView，并将其添加到它的视图层次 onDestroyView（）删除的MapView从视图层次结构 fragment's onCreateView() simply returns a new FrameLayout fragment's onActivityCreated() gets the MapView from the Acitivity and adds it to its view hierarchy onDestroyView() removes the MapView from its view hierarchy

现在我想使用XML定义的布局，这样我可以有一些其他的UI东西的片段。把图形页面元素的布局文件老是死机，所以我做这种方式：

Now I would like the fragment to use a layout defined in xml so that I can have some other UI stuff. Putting the MapView element in the layout file always crashes, so I'm doing it this way:

map_screen_fragment.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" >


    <FrameLayout
        android:id="@+id/map_container"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >
    </FrameLayout>

</LinearLayout>

我的 MapScreenActivity 保存实际图形页面，和片段呼叫 getMapView（），所以我不碰上了不能有超过一个图形页面的问题：

My MapScreenActivity holds the actual MapView, and the fragment calls getMapView(), so I don't run into the "can't have more than one MapView" issue:

MapScreenActivity.java

public class MapScreenActivity extends FragmentActivity {
    protected Fragment fragment;
    protected MapView mapView;

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

        if (savedInstanceState == null) {
            fragment = new MapScreenFragment();

            getSupportFragmentManager().beginTransaction().add(R.id.root_container, fragment)
                    .commit();
        }
    }

    public MapView getMapView() {
        if (mapView == null) {
            mapView = new MapView(this, getResources().getString(R.string.maps_api_key));
        }

        return mapView;
    }
}

MapScreenFragment.java

public class MapScreenFragment extends Fragment {
    protected ViewGroup mapContainer;
    protected MapView mapView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle args) {
        View root = inflater.inflate(R.layout.map_screen_fragment, container);
        mapContainer = (ViewGroup) root.findViewById(R.id.map_container);
        return root;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        mapView = ((MapScreenActivity) getActivity()).getMapView();
        mapView.setClickable(true);
        mapView.setBuiltInZoomControls(true);

        mapContainer.addView(mapView);

    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        mapContainer.removeView(mapView);
    }   

}

在理论上，这应该所有的工作方式相同新的FrameLayout 方法首先描述。不过，我得到这个每次：

In theory, this should all work the same way as the new FrameLayout method first described. However, I get this every time:

02-24 18:01:28.139: E/AndroidRuntime(502): FATAL EXCEPTION: main
02-24 18:01:28.139: E/AndroidRuntime(502): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.mapfragment/com.example.mapfragment.MapScreenActivity}: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.os.Handler.dispatchMessage(Handler.java:99)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.os.Looper.loop(Looper.java:130)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.app.ActivityThread.main(ActivityThread.java:3683)
02-24 18:01:28.139: E/AndroidRuntime(502):  at java.lang.reflect.Method.invokeNative(Native Method)
02-24 18:01:28.139: E/AndroidRuntime(502):  at java.lang.reflect.Method.invoke(Method.java:507)
02-24 18:01:28.139: E/AndroidRuntime(502):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-24 18:01:28.139: E/AndroidRuntime(502):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-24 18:01:28.139: E/AndroidRuntime(502):  at dalvik.system.NativeStart.main(Native Method)
02-24 18:01:28.139: E/AndroidRuntime(502): Caused by: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.view.ViewGroup.addViewInner(ViewGroup.java:1976)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.view.ViewGroup.addView(ViewGroup.java:1871)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.view.ViewGroup.addView(ViewGroup.java:1828)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.view.ViewGroup.addView(ViewGroup.java:1808)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.support.v4.app.NoSaveStateFrameLayout.wrap(Unknown Source)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.support.v4.app.FragmentManagerImpl.moveToState(Unknown Source)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.support.v4.app.FragmentManagerImpl.moveToState(Unknown Source)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.support.v4.app.BackStackRecord.run(Unknown Source)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.support.v4.app.FragmentManagerImpl.execPendingActions(Unknown Source)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.support.v4.app.FragmentActivity.onStart(Unknown Source)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1129)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.app.Activity.performStart(Activity.java:3791)
02-24 18:01:28.139: E/AndroidRuntime(502):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1620)
02-24 18:01:28.139: E/AndroidRuntime(502):  ... 11 more

我试图消除了图形页面从其父从返回前getMapView（），并且仍然崩溃。我真不明白为什么这种方法是行不通的，任何帮助都将是AP preciated。

I've tried removing the the MapView from it's parent before returning from getMapView(), and that still crashes. I really don't understand why this approach doesn't work, any help at all would be appreciated.

推荐答案

我不知道这是否是同样的问题，因为你是有，但事实证明，膨胀是正常的，只要你不重视根。

I'm not sure if this is the same problem as you were having, but it turns out that inflating is okay, so long as you don't attach to the root.

例如，你需要做的是这样的：

For example, you need to do something like this:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    return inflater.inflate(R.id.my_layout, container, false);
}

如果你没有到最后假参数添加到膨胀（）通话，那么你将得到的IllegalStateException异常。

If you fail to add that last false argument to the inflate() call, then you will get the IllegalStateException.

我认为正在发生的事情是，如果没有额外的假的说法，你的膨胀视图树被附加到根视图（容器），然后，当活动开始后，系统会尝试在视图树添加到根了。因此，错误。

I think what is happening is that without the extra false argument, your inflated view tree is attached to the root view (container) and then when the Activity is started, the system attempts to add the view tree to the root again. Hence the error.