Java 返回地图时带有MapFragment黑屏的Android抽屉布局

我一直在试验android.support.v4.widget.DrawerLayout，其中有4个片段可供选择。地图最初加载时没有问题，但是当我打开抽屉并更改片段时，我无法返回地图。我刚得到一个黑屏。Logcat显示碎片被重新创建，但我什么也没得到。只是一个空白的黑屏。我可以毫无问题地在其他片段之间切换。我做错了什么？我的项目的最小API为14

我从

MainActivity.java

这里加载

ExploreMap

（一个片段）：

        if (position == 0){
            ExploreMap exMap = new ExploreMap();
            exMap.setRetainInstance(true);
            getFragmentManager().beginTransaction().replace(R.id.content_frame, exMap).commit();
        }

在

ExploreMap.java

中，我执行以下操作

public class ExploreMap extends Fragment implements OnInfoWindowClickListener, android.location.LocationListener, OnMapLongClickListener{

 private LocationManager mLocManager;
 private GoogleMap mMap;
 private MapFragment mMapFragment;

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

        FragmentManager fm = getActivity().getFragmentManager();
        mMapFragment = (MapFragment) fm.findFragmentById(R.id.map);


        if (mMapFragment == null) {
            mMapFragment = MapFragment.newInstance();
            fm.beginTransaction().replace(R.id.map, mMapFragment).commit();
        }


        if (savedInstanceState == null) {
            // First incarnation of this activity.
            mMapFragment.setRetainInstance(true);
        }else {
            // Reincarnated activity. The obtained map is the same map instance in the previous
            // activity life cycle. There is no need to reinitialize it.
            mMap = mMapFragment.getMap();
        }

        createMapIfNeeded();


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




    @Override
    public void onResume() {
        super.onResume();
        //create the map
       createMapIfNeeded();  
    }





    private void createMapIfNeeded(){

        if(mLocManager == null){
            mLocManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
            mLocManager.requestLocationUpdates(
                       LocationManager.NETWORK_PROVIDER,
                       MIN_TIME_BW_UPDATES,
                       MIN_DISTANCE_CHANGE_FOR_UPDATES,
                       this);
        }

         //locmanager can return null if no last known locaiton is available.
        location = mLocManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);


        //if a map has not already been instantiated it'll return null
        if(mMap == null){
            //instantiate map
            mMap = mMapFragment.getMap();
            //check it has been instantiated

            if(mMap != null){   
                mMap.setOnMapLongClickListener(this);
                mMap.setOnInfoWindowClickListener(this);
                mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
                mMap.setMyLocationEnabled(true);

                //Manipulate map here (add coordinates/polylines from trip etc etc.)
                UiSettings setting = mMap.getUiSettings();
                setting.setTiltGesturesEnabled(true);
                setting.setRotateGesturesEnabled(true);
                setting.setZoomControlsEnabled(true);
                setting.setMyLocationButtonEnabled(true);

                if(location != null){
                CameraUpdate cu = CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(), location.getLongitude()), 15);
                mMap.animateCamera(cu);
                }
            }
        }  
    }

XML的特性如下

 mainactivity_layout.xml
<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!-- As the main content view, the view below consumes the entire
         space available using match_parent in both dimensions. -->
    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <!-- android:layout_gravity="start" tells DrawerLayout to treat
         this as a sliding drawer on the left side for left-to-right
         languages and on the right side for right-to-left languages.
         The drawer is given a fixed width in dp and extends the full height of
         the container. A solid background is used for contrast
         with the content view. -->
    <ListView
        android:id="@+id/left_drawer"
        android:layout_width="240dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:choiceMode="singleChoice"
        android:divider="@android:color/transparent"
        android:dividerHeight="0dp"
        android:background="#111"/>
</android.support.v4.widget.DrawerLayout>

---

我希望这对你有用：

---

在我的头撞了几天墙之后，我发现了问题，或者应该说是问题。tsp建议使用上面的库，这些库也可以使用，但是我想让它与Google提供的android.support.v4.widget.DrawerLayout一起使用

这个问题有两个方面

我使用的是嵌套片段，在离开ExploreMap片段时没有删除子（map）片段。我的等级是：Activity（抽屉布局）-->ExploreMap（一个片段）-->MapFragment。当打开抽屉并更改片段时，我并没有从ExploreMap（片段）中删除MapFragment。由于

setRetainInstance（true）

，原始MapFragment实例保留在内存中。由于某些原因，我仍然不完全理解MapFragment的原始实例在返回到ExploreMap片段后不会重新出现。为了解决这个问题，我在最初创建MapFragment时为它分配了一个名为“mapfrag”的字符串标记，并将变量设置为

public static

。接下来在活动中，抽屉代码将切换片段，我执行一个

findFragmentByTag（）

并测试其

null

，如果它不为null，则删除MapFragment

但是#1只会让你半途而废，因为当你返回到ExploreMap时，它会让地图重新出现。然而，来自MapFragment的基础

GoogleMap

不断向我返回null，我根本无法配置地图

2） 我找到了这个帖子。它建议扩展您自己的MapFragment并实现一个接口，以便在创建MapFragment时发出通知，这在很大程度上保证了非空GoogleMap

真倒霉！！你有一个谷歌地图在谷歌抽屉布局。这是我的完整工作代码

MainActivity.java
 if (position == 0){
                exMap = new ExploreMap();
                exMap.setRetainInstance(true);
                getFragmentManager().beginTransaction().replace(R.id.content_frame, exMap).commit();
            }
            if(position == 1){  
                //remove map frag here instead of in explore map
                Fragment f = getFragmentManager().findFragmentByTag("mapfrag");
                if(f != null){
                     getFragmentManager().beginTransaction().remove(f).commit();
                }

                Ms fragment = new Ms();
                getFragmentManager().beginTransaction().replace(R.id.content_frame, fragment).commit(); 
            }
            if(position == 2){
                Fragment f = getFragmentManager().findFragmentByTag("mapfrag");
                if(f != null){
                     getFragmentManager().beginTransaction().remove(f).commit();
                }
                Settings fragment = new Settings();
                getFragmentManager().beginTransaction().replace(R.id.content_frame, fragment).commit(); 
            }
            if(position == 3){
                Fragment f = getFragmentManager().findFragmentByTag("mapfrag");
                if(f != null){
                     getFragmentManager().beginTransaction().remove(f).commit();
                }
                About fragment = new About();
                getFragmentManager().beginTransaction().replace(R.id.content_frame, fragment).commit(); 
            }

在

ExploreMap.java中

public class ExploreMap extends Fragment implements MyMapFragment.MapCallback,  OnInfoWindowClickListener, android.location.LocationListener, OnMapLongClickListener{

     private LocationManager mLocManager;
     private GoogleMap mMap;
     public static MyMapFragment mMapFragment;

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


            FragmentManager fm = getActivity().getFragmentManager();
            mMapFragment = (MyMapFragment) fm.findFragmentById(R.id.map_framelayout);


            if (mMapFragment == null) {
                mMapFragment = new MyMapFragment();
                mMapFragment.setRetainInstance(true);
                mMapFragment.setMapCallback(this);
                fm.beginTransaction().replace(R.id.map_framelayout, mMapFragment,"mapfrag").commit();
            }

            createMapIfNeeded();

            return v;
        }



        @Override
        public void onMapReady(GoogleMap map) {
            createMapIfNeeded();
        }   

private void createMapIfNeeded(){

            if(mLocManager == null){
                mLocManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
                mLocManager.requestLocationUpdates(
                           LocationManager.NETWORK_PROVIDER,
                           MIN_TIME_BW_UPDATES,
                           MIN_DISTANCE_CHANGE_FOR_UPDATES,
                           this);
            }

             //locmanager can return null if no last known locaiton is available.
            location = mLocManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);


            //if a map has not already been instantiated it'll return null
            if(mMap == null){
                //instantiate map
                mMap = mMapFragment.getMap();


                //check it has been instantiated
                if(mMap != null){
                    mMap.setOnMapLongClickListener(this);
                    mMap.setOnInfoWindowClickListener(this);
                    mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
                    mMap.setMyLocationEnabled(true);

                    //Manipulate map here (add coordinates/polylines from trip etc etc.)
                    UiSettings setting = mMap.getUiSettings();
                    setting.setTiltGesturesEnabled(true);
                    setting.setRotateGesturesEnabled(true);
                    setting.setZoomControlsEnabled(true);
                    setting.setMyLocationButtonEnabled(true);

                    if(location != null){
                    CameraUpdate cu = CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(), location.getLongitude()), 15);
                    mMap.animateCamera(cu);
                    }
                }
            }  
        }

public class MyMapFragment extends MapFragment{



      private MapCallback callback;

      public static interface MapCallback
      {
         public void onMapReady(GoogleMap map);
      }

      public void setMapCallback(MapCallback callback)
      {
        this.callback = callback;
      }

      @Override public void onActivityCreated(Bundle savedInstanceState)
      {
          super.onActivityCreated(savedInstanceState);
         if(callback != null) callback.onMapReady(getMap());     
      }


}

现在
MyMapFragment.java

public class ExploreMap extends Fragment implements MyMapFragment.MapCallback,  OnInfoWindowClickListener, android.location.LocationListener, OnMapLongClickListener{

     private LocationManager mLocManager;
     private GoogleMap mMap;
     public static MyMapFragment mMapFragment;

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


            FragmentManager fm = getActivity().getFragmentManager();
            mMapFragment = (MyMapFragment) fm.findFragmentById(R.id.map_framelayout);


            if (mMapFragment == null) {
                mMapFragment = new MyMapFragment();
                mMapFragment.setRetainInstance(true);
                mMapFragment.setMapCallback(this);
                fm.beginTransaction().replace(R.id.map_framelayout, mMapFragment,"mapfrag").commit();
            }

            createMapIfNeeded();

            return v;
        }



        @Override
        public void onMapReady(GoogleMap map) {
            createMapIfNeeded();
        }   

private void createMapIfNeeded(){

            if(mLocManager == null){
                mLocManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
                mLocManager.requestLocationUpdates(
                           LocationManager.NETWORK_PROVIDER,
                           MIN_TIME_BW_UPDATES,
                           MIN_DISTANCE_CHANGE_FOR_UPDATES,
                           this);
            }

             //locmanager can return null if no last known locaiton is available.
            location = mLocManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);


            //if a map has not already been instantiated it'll return null
            if(mMap == null){
                //instantiate map
                mMap = mMapFragment.getMap();


                //check it has been instantiated
                if(mMap != null){
                    mMap.setOnMapLongClickListener(this);
                    mMap.setOnInfoWindowClickListener(this);
                    mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
                    mMap.setMyLocationEnabled(true);

                    //Manipulate map here (add coordinates/polylines from trip etc etc.)
                    UiSettings setting = mMap.getUiSettings();
                    setting.setTiltGesturesEnabled(true);
                    setting.setRotateGesturesEnabled(true);
                    setting.setZoomControlsEnabled(true);
                    setting.setMyLocationButtonEnabled(true);

                    if(location != null){
                    CameraUpdate cu = CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(), location.getLongitude()), 15);
                    mMap.animateCamera(cu);
                    }
                }
            }  
        }

public class MyMapFragment extends MapFragment{



      private MapCallback callback;

      public static interface MapCallback
      {
         public void onMapReady(GoogleMap map);
      }

      public void setMapCallback(MapCallback callback)
      {
        this.callback = callback;
      }

      @Override public void onActivityCreated(Bundle savedInstanceState)
      {
          super.onActivityCreated(savedInstanceState);
         if(callback != null) callback.onMapReady(getMap());     
      }


}

干杯
 在邮件线程上找到此问题的简易解决方法。这解决了我的问题。
使用相对布局并将此透明视图直接放置在上方
你的地图碎片。例如：

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

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

    <View
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:background="@android:color/transparent" />
</RelativeLayout>


感谢您的推荐，但是我不认为使用上述工具与使用谷歌提供的android.support.v4.widget.DrawerLayout有什么不同。功能是一样的，我想我会得到同样的结果。您是否成功地使用此库在抽屉中获取mapfragment？我正在努力编译示例应用程序。我已经导入了示例和依赖库，但是示例项目无法解析“R”。做了通常清洁的项目，但没有。我注意到有一个“./ABS”无法解析，但我不知道它位于何处，也不知道它是什么。有什么想法吗？