Question

我有一个MainActivity，它有一个带有两个标签的ActionBar，第一个标签用于显示传感器数据值，第二个标签用于显示Map。但是我在第二个标签上的片段中实现地图有问题

MainActivity如下所示：

public class MainActivity extends Activity
{
private static final String DATA_FRAGMENT_BAR = "Data";
private static final String MAP_FRAGMENT_BAR = "Map";

private DataCollection mDataCollection;

@Override
protected void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Config.mContext = this;
    ActionBar actionBar = getActionBar();
    actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_HOME| ActionBar.DISPLAY_SHOW_CUSTOM);
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    ActionBar.Tab dataTab = actionBar.newTab().setText(DATA_FRAGMENT_BAR);
    ActionBar.Tab mapTab = actionBar.newTab().setText(MAP_FRAGMENT_BAR);
    Fragment dataFragment = new FragmentData();
    Fragment mapFragment = new FragmentMap();

    dataTab.setTabListener(new MyTabsListener(dataFragment));
    mapTab.setTabListener(new MyTabsListener(mapFragment));

    actionBar.addTab(dataTab);
    actionBar.addTab(mapTab);
    mDataCollection = DataCollection.getInstance();
}
....
}

TabsListener如下所示公共类MyTabsListener实现ActionBar.TabListener { 私有片段片段;

public MyTabsListener(Fragment fragment)
{
    this.fragment = fragment;
}

@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub
}

@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub
    ft.replace(R.id.fragment_container, fragment);
}

@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub
    ft.remove(fragment);
}
}

地图片段类如下所示：

public class FragmentMap extends Fragment
{

MapView mapView;
GoogleMap map;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
{
    View v = inflater.inflate(R.layout.fragment_map, container, false);
    // Gets the MapView from the XML layout and creates it
    mapView = (MapView) v.findViewById(R.id.mapView);
    mapView.onCreate(savedInstanceState);

    // Gets to GoogleMap from the MapView and does initialization stuff
    map = mapView.getMap();
    //map.getUiSettings().setMyLocationButtonEnabled(false);
    //map.setMyLocationEnabled(true);
    map.addMarker(new MarkerOptions().position(new LatLng(50.167003,19.383262)));


    // Needs to call MapsInitializer before doing any CameraUpdateFactory calls
    try 
    {
        MapsInitializer.initialize(this.getActivity());
    } 
    catch (GooglePlayServicesNotAvailableException e)
    {
        e.printStackTrace();
    }

    // Updates the location and zoom of the MapView
    CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(new LatLng(43.1, -87.9), 10);
    map.animateCamera(cameraUpdate);

    return v;
}

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

@Override
public void onDestroy() 
{
    super.onDestroy();
    mapView.onDestroy();
}

@Override
public void onLowMemory()
{
    super.onLowMemory();
    mapView.onLowMemory();
}
}

我在FragmentMap类的“mapView.onCreate（savedInstanceState）;”行设置了一个断点。 savedInstanceState为null，程序将在行后崩溃。

有人可以提供帮助。提前谢谢。

Answer 1

Google发布了Map API版本2.这为您提供了MapFragment和SupportMapFragment。这允许您在不扩展MapActivity的情况下添加Map。

Google Maps v2 In fragment cashes when clicked twice

Answer 2

文档中并不是很清楚，但应在 MapView.onCreate() 中调用Fragment.onActivityCreated()方法，而不是Fragment.onCreate()

此外，MapView.getMap()可以返回null，不要忘记检查。

您应该在super.onResume()

之前致电mapView.onResume()

如何在片段中实现谷歌地图

2 个答案: