Android和Google Map API v2 - 显示地图时显示为空

Question

我在努力让Google Map API v2片段能够正常工作。我已经仔细检查了API密钥和权限，但是当尝试显示地图时，我仍然得到了空值。下面是我的清单：

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.hanu.eateries" 
    android:versionCode="1" 
    android:versionName="1.0" > 

    <uses-sdk 
     android:minSdkVersion="8" 
     android:targetSdkVersion="17" /> 

    <permission 
      android:name="com.hanu.eateries.permission.MAPS_RECEIVE" 
      android:protectionLevel="signature"/> 
    <uses-permission android:name="com.hanu.eateries.permission.MAPS_RECEIVE"/> 
    <uses-permission android:name="android.permission.INTERNET" /> 
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> 
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> 
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> 
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" /> 
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> 

    <uses-feature 
      android:glEsVersion="0x00020000" 
      android:required="true"/> 

    <application 
     android:icon="@drawable/ic_launcher" 
     android:label="@string/app_name" 
     android:theme="@style/AppTheme" 
     android:allowBackup="true" 
     android:uiOptions="splitActionBarWhenNarrow" > 
     <meta-data 
      android:name="com.google.android.maps.v2.API_KEY" 
      android:value="@string/mapApiKey" /> 
     <activity 
      android:name=".DashboardActivity" 
      android:label="@string/title_activity_main" > 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 
       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     <activity android:name=".LoginActivity" /> 
     <activity android:name=".RegisterActivity" /> 
     <activity android:name=".PlaceListActivity" /> 
     <activity android:name=".WelcomeActivity" /> 
     <activity android:name=".PlaceViewActivity" /> 
     <activity android:name=".AccountActivity"/> 
     <activity android:name=".SettingsActivity" /> 
     <activity android:name=".SettingsActivityLogin" /> 

    </application> 

</manifest> 

这里是我的代码：

public class PlaceLocationFragment extends Fragment{ 
    private GoogleMap myMap; 
    final int RQS_GooglePlayServices = 1; 

    private static final double GEO_CONVERSION = 1E6; 

    @Override 
     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     View view = inflater.inflate(R.layout.location_view, container, false); 
     initLayout(); 
     return view; 
     } 

    private void initLayout(){ 
     FragmentManager myFragmentManager = getActivity().getSupportFragmentManager(); 
     SupportMapFragment mySupportMapFragment = (SupportMapFragment) myFragmentManager.findFragmentById(R.id.map); 

     myMap = mySupportMapFragment.getMap(); 
     myMap.setMyLocationEnabled(true); 
     myMap.setMapType(GoogleMap.MAP_TYPE_NORMAL); 

     Intent intent = getActivity().getIntent(); 
     double spotLat = intent.getDoubleExtra("LAT", 21.139); 
     double spotLng = intent.getDoubleExtra("LNG", 105.851); 
     int latitude = (int) (spotLat * GEO_CONVERSION); 
     int longitude = (int) (spotLng * GEO_CONVERSION); 
     LatLng point = new LatLng(latitude, longitude); 

     myMap.addMarker(new MarkerOptions().position(point).title(intent.getStringExtra("NAME") + "\n" + intent.getStringExtra("ADD"))); 
     myMap.getUiSettings().setCompassEnabled(true); 
     myMap.getUiSettings().setZoomControlsEnabled(true); 
     myMap.animateCamera(CameraUpdateFactory.newLatLng(point)); 

    } 

    @Override 
    public void onResume(){ 
     super.onResume(); 
     super.onResume(); 
     int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getActivity().getApplicationContext()); 

     if (resultCode == ConnectionResult.SUCCESS){ 
      Toast.makeText(getActivity().getApplicationContext(), 
      "isGooglePlayServicesAvailable SUCCESS", 
      Toast.LENGTH_LONG).show(); 
     }else{ 
      GooglePlayServicesUtil.getErrorDialog(resultCode, getActivity(), RQS_GooglePlayServices); 
     } 
    } 
} 

而且logcat中指出的错误行myMap.setMyLocationEnabled(true);：

03-09 13:52:31.101: E/AndroidRuntime(802): FATAL EXCEPTION: main 
03-09 13:52:31.101: E/AndroidRuntime(802): java.lang.NullPointerException 
03-09 13:52:31.101: E/AndroidRuntime(802): at com.hanu.eateries.PlaceLocationFragment.initLayout(PlaceLocationFragment.java:39) 
03-09 13:52:31.101: E/AndroidRuntime(802): at com.hanu.eateries.PlaceLocationFragment.onCreateView(PlaceLocationFragment.java:30) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.app.Fragment.performCreateView(Fragment.java:1460) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:911) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:461) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.view.ViewPager.populate(ViewPager.java:1012) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:523) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:495) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:476) 
03-09 13:52:31.101: E/AndroidRuntime(802): at com.hanu.eateries.PlaceViewActivity$2.onTabSelected(PlaceViewActivity.java:63) 
03-09 13:52:31.101: E/AndroidRuntime(802): at com.actionbarsherlock.internal.app.ActionBarWrapper$TabWrapper.onTabSelected(ActionBarWrapper.java:344) 
03-09 13:52:31.101: E/AndroidRuntime(802): at com.android.internal.app.ActionBarImpl.selectTab(ActionBarImpl.java:570) 
03-09 13:52:31.101: E/AndroidRuntime(802): at com.android.internal.app.ActionBarImpl$TabImpl.select(ActionBarImpl.java:1067) 
03-09 13:52:31.101: E/AndroidRuntime(802): at com.android.internal.widget.ScrollingTabContainerView$TabClickListener.onClick(ScrollingTabContainerView.java:519) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.view.View.performClick(View.java:4202) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.view.View$PerformClick.run(View.java:17340) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.os.Handler.handleCallback(Handler.java:725) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.os.Handler.dispatchMessage(Handler.java:92) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.os.Looper.loop(Looper.java:137) 
03-09 13:52:31.101: E/AndroidRuntime(802): at android.app.ActivityThread.main(ActivityThread.java:5039) 
03-09 13:52:31.101: E/AndroidRuntime(802): at java.lang.reflect.Method.invokeNative(Native Method) 
03-09 13:52:31.101: E/AndroidRuntime(802): at java.lang.reflect.Method.invoke(Method.java:511) 
03-09 13:52:31.101: E/AndroidRuntime(802): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
03-09 13:52:31.101: E/AndroidRuntime(802): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
03-09 13:52:31.101: E/AndroidRuntime(802): at dalvik.system.NativeStart.main(Native Method) 

编辑：我location_view.xml：

<?xml version="1.0" encoding="utf-8"?> 
    <fragment xmlns:android="http://schemas.android.com/apk/res/android" 
     android:id="@+id/map" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     class="com.google.android.gms.maps.SupportMapFragment"/> 

这里有什么问题？如果您有任何建议，请让我知道。谢谢。

Answer 1

原来这不起作用的原因是我将API密钥引用到字符串。当我尝试将密钥直接放入Manifest文件时，它可以正常工作！这很奇怪，但我很高兴现在问题解决了。

Answer 2

其实我认为问题在于你试图在Fragment的内部放置一个MapFragment。不允许使用Fragment级联。所有地图/标记操作代码：

FragmentManager myFragmentManager = getActivity().getSupportFragmentManager(); 
    SupportMapFragment mySupportMapFragment = (SupportMapFragment) myFragmentManager.findFragmentById(R.id.map); 

    myMap = mySupportMapFragment.getMap(); 
    myMap.setMyLocationEnabled(true); 
    myMap.setMapType(GoogleMap.MAP_TYPE_NORMAL); 

    Intent intent = getActivity().getIntent(); 
    double spotLat = intent.getDoubleExtra("LAT", 21.139); 
    double spotLng = intent.getDoubleExtra("LNG", 105.851); 
    int latitude = (int) (spotLat * GEO_CONVERSION); 
    int longitude = (int) (spotLng * GEO_CONVERSION); 
    LatLng point = new LatLng(latitude, longitude); 

    myMap.addMarker(new MarkerOptions().position(point).title(intent.getStringExtra("NAME") + "\n" + intent.getStringExtra("ADD"))); 
    myMap.getUiSettings().setCompassEnabled(true); 
    myMap.getUiSettings().setZoomControlsEnabled(true); 
    myMap.animateCamera(CameraUpdateFactory.newLatLng(point)); 

应该去活动/ FragmentActivity使用包含您的MapFragment布局内。