2

我一直在尝试android.support.v4.widget.DrawerLayout并从抽屉中选择 4 个碎片。地图最初加载没有问题，但是当我打开抽屉并更改片段时，我无法返回地图。我只是得到一个黑屏。Logcat 显示片段已重新创建，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。我究竟做错了什么？我的项目的最小 API 为 14。

我从这里加载ExploreMap（一个片段）MainActivity.java：

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

在ExploreMap.java我做以下

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>

和exploremap_layout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >


        <FrameLayout
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>
4

3 回答 3

2

经过几天的头撞墙后，我发现了问题，或者我应该说问题。tsp 建议使用上面也可以使用的库，但是我想让它与 Google 提供的android.support.v4.widget.DrawerLayout.

问题是 2 倍。

  1. 我正在使用嵌套片段，并且在离开 ExploreMap 片段时我没有删除子（地图）片段。我的层次是：Activity(DrawerLayout)-->ExploreMap(A Fragment)-->MapFragment。打开抽屉并更改片段时，我没有从 ExploreMap(fragment) 中删除 MapFragment。原始 MapFragment 实例由于setRetainInstance(true). 由于我仍然不完全理解 MapFragment 的原始实例在返回到 ExploreMap 片段后不会重新出现的原因。为了解决这个问题，我在 MapFragment 最初创建时为它分配了一个名为“mapfrag”的字符串标签，并将变量设置为public static. 接下来在 Activity 中，抽屉代码用于切换片段，我执行 afindFragmentByTag()并测试其是否为null，如果 MapFragment 不为空，则删除它。

然而，#1 只能让你走一半，因为当你返回 ExploreMap 时它会让地图重新出现，但是GoogleMapMapFragment 的底层一直向我返回 null，我根本无法配置地图。

2）我发现这篇文章MapFragment return null。其中建议扩展您自己的 MapFragment 并实现一个接口来通知 MapFragment 何时创建完成，几乎可以保证非空 GoogleMap。

和 WHAMMY ！你在谷歌抽屉布局中有一个工作谷歌地图。这是我完整的工作代码。

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

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);
                    }
                }
            }  
        }

现在MyMapFragment.java

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！！！

于 2013-10-25T03:33:30.500 回答
0

我希望这对你有用： https ://github.com/jfeinstein10/SlidingMenu https://play.google.com/store/apps/details?id=com.slidingmenu.example&hl=en

于 2013-10-18T04:41:07.407 回答
-1

在邮件线程中找到此问题的简单解决方法。这解决了我的问题。使用相对布局并将这个透明视图直接放在您的地图片段上。例子 ：

<?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>
于 2014-06-12T13:42:36.713 回答