mapFragment.getMap()为空时,用户做一个设备屏幕旋转

问题描述 投票:0回答:3

我创建了一个Android应用程序,其中:

  • 显示谷歌地图
  • 检索用户的地理定位和缩放地图,在这个地缘禄
  • 通过检索Web服务的JSON,并创建一些标记

该应用程序的工作原理,当给它的用户访问的第一次。

但是,当他转动他的设备屏幕/时,他改变了方向,地图不能被初始化。

在我的onResume方法我初始化mapFragment,如果它不等于空,我为了并初始化我的GoogleMap的地图属性做的GetMap()。

public class MapsActivity extends ActionBarActivity implements LocationListener, GoogleApiClient.ConnectionCallbacks,
    GoogleApiClient.OnConnectionFailedListener {

...

@Override
protected void onResume() {
    Log.d(LOG_TAG, "onResume");
    super.onResume();

    if(googleApiClient != null) {
        googleApiClient.connect();

        mapFragment = (MapFragment) getFragmentManager().findFragmentById(R.id.map);
        if(mapFragment != null) {
            Log.d(LOG_TAG, "mapFragment initialized");
        } else {
            Log.d(LOG_TAG, "error during mapFragment initialization");
        }
        map = mapFragment.getMap();
        if(map != null) {
            Log.d(LOG_TAG, "map initialized");
        } else {
            Log.d(LOG_TAG, "error during map initialization");
        }

    }
    Log.d(LOG_TAG, "end of onResume");
}

当该活动的用户访问,它的工作:

12-17 09:35:02.306  25099-25099/com.xxx.xx D/LogMe﹕ onCreate
12-17 09:35:03.746  25099-25099/com.xxx.xx D/LogMe﹕ end of onCreate
12-17 09:35:03.748  25099-25099/com.xxx.xx D/LogMe﹕ onResume
12-17 09:35:03.759  25099-25099/com.xxx.xx D/LogMe﹕ mapFragment initialized
12-17 09:35:03.760  25099-25099/com.xxx.xx D/LogMe﹕ map initialized
12-17 09:35:03.760  25099-25099/com.xxx.xx D/LogMe﹕ end of onResume
12-17 09:35:03.844  25099-25099/com.xxx.xx D/LogMe﹕ onConnected
12-17 09:35:03.848  25099-25099/com.xxx.xx D/LogMe﹕ google play services available
12-17 09:35:03.850  25099-25099/com.xxx.xx D/LogMe﹕ setUpMapIfNeeded
12-17 09:35:03.850  25099-25099/com.xxx.xx D/LogMe﹕ we have a map
12-17 09:35:03.865  25099-25099/com.xxx.xx D/LogMe﹕ setUpMap
12-17 09:35:03.866  25099-25099/com.xxx.xx D/LogMe﹕ location: Location[mProvider=fused,mTime=1418805217845,mLatitude=43.6137752,mLongitude=1.4302528,mHasAltitude=false,mAltitude=0.0,mHasSpeed=false,mSpeed=0.0,mHasBearing=false,mBearing=0.0,mHasAccuracy=true,mAccuracy=52.5,mExtras=null]
12-17 09:35:03.867  25099-25099/com.xxx.xx D/LogMe﹕ we retrieve markers thx to the web service

但是,当他旋转手机屏幕:

12-17 09:35:25.118  25099-25099/com.xxx.xx D/LogMe﹕ onSaveInstanceState
12-17 09:35:25.119  25099-25099/com.xxx.xx D/LogMe﹕ end of onSaveInstanceState
12-17 09:35:25.260  25099-25099/com.xxx.xx D/LogMe﹕ onCreate
12-17 09:35:25.427  25099-25099/com.xxx.xx D/LogMe﹕ lat et lng: lat/lng: (43.613774948887695,1.4302530884742737)
12-17 09:35:25.428  25099-25099/com.xxx.xx D/LogMe﹕ zoom: 13.0
12-17 09:35:25.430  25099-25099/com.xxx.xx D/LogMe﹕ markers retrieved
12-17 09:35:25.462  25099-25099/com.xxx.xx D/LogMe﹕ end of onCreate
12-17 09:35:25.470  25099-25099/com.xxx.xx D/LogMe﹕ onResume
12-17 09:35:25.609  25099-25099/com.xxx.xx D/LogMe﹕ mapFragment initialized
12-17 09:35:25.609  25099-25099/com.xxx.xx D/LogMe﹕ error during map initialization
12-17 09:35:25.609  25099-25099/com.xxx.xx D/LogMe﹕ end of onResume
12-17 09:35:25.732  25099-25099/com.xxx.xx D/LogMe﹕ onConnected
12-17 09:35:25.735  25099-25099/com.xxx.xx D/LogMe﹕ google play services available
12-17 09:35:25.736  25099-25099/com.xxx.xx D/LogMe﹕ setUpMapIfNeeded
12-17 09:36:28.522  25099-25099/com.xxx.xx D/LogMe﹕ onSaveInstanceState

地图不能被初始化。

你有一个想法?

谢谢

android google-maps rotation google-maps-android-api-2 android-maps-v2
3个回答
0
投票

你可以尝试得到这样的地图:

 protected void onResume() {
        if (mMap != null) {
            // Do markers
            return;
        }
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
        if (mMap == null) {
            return;
        }
 }

另外,样本项目叫做hello-map here。它显示了map rotation.没问题


0
投票

避免使用XML来构建的MapView / SupportMapFragment。使用FrameLayout里,做一个有SupportMapFragment的新实例代替。你可以做更多的与它(加上ChildFragmentManager和更多...)。

private MapView mMapView;
private SupportMapFragment mSupportMapFragment;

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

@Override
public void onResume() {
    super.onResume();
    setUpMapIfNeeded();
}


private void createMapFragmentIfNeeded() {

    mFragmentManager = getChildFragmentManager();

    if (mSupportMapFragment == null) {

        mSupportMapFragment = createMapFragment();
        FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.map_view, mSupportMapFragment);
        fragmentTransaction.commit();

    }
}

public void  setUpMapIfNeeded() {
    if (mMap == null && mSupportMapFragment != null) {
        mMap = mSupportMapFragment.getMap();
        if (mMap != null) {
            //Setup map
        }
    }
}

protected SupportMapFragment createMapFragment() {
    try {
        return SupportMapFragment.class.newInstance();
    } catch (java.lang.InstantiationException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }
    return null;
}

0
投票

我已经解决了一个新的类创建RetainMapFragment我的问题:

import android.os.Bundle;

import com.google.android.gms.maps.MapFragment;

public class RetainMapFragment extends MapFragment {

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

}

我用我的布局这个新类:

<fragment
    android:id="@+id/map"
    android:layout_width="match_parent"
    android:layout_height="0px"
    android:layout_weight="3"
    android:layout_margin="5px"
    class="com.xxx.xxx.RetainMapFragment"/>
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