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我有一个 MainActivity，它有一个带有两个选项卡的 ActionBar，第一个选项卡是显示传感器数据值，第二个选项卡是我想显示地图。但是我在第二个选项卡的片段中实现地图时遇到问题

MainActivity 如下图所示：

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 public class MyTabsListener implements ActionBar.TabListener { private Fragment fragment;

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“mapView.onCreate(savedInstanceState);”行的 FragmentMap 类中设置了一个断点 savedInstanceState 为空，程序将在行后崩溃。

有人可以帮忙吗。提前致谢。

4

2 回答 2

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Google released the Map API Version 2. This gives you a MapFragment and a SupportMapFragment. This allows you to add a Map without extending MapActivity.

Google Maps v2 In fragment cashes when clicked twice

于 2013-10-14T11:33:50.330 回答
0

文档中不是很清楚，但是MapView.onCreate()应该在 中调用该方法Fragment.onActivityCreated()，而不是在Fragment.onCreate()

此外，MapView.getMap()可以返回 null，不要忘记检查。

你应该super.onResume()先打电话mapView.onResume()

于 2013-10-14T11:40:56.440 回答