谷歌地图碎片返回null片段内 [英] Google Maps Fragment returning null inside a fragment
问题描述
所以，我有一个包含地图片段的空片段。每当我尝试激活包含地图的片段，我的应用程序崩溃，在这条线返回一个空指针错误：
So I have an empty fragment that contains a map fragment. Whenever I try to activate the fragment containing the map, my app crashes and returns a null pointer error on this line:
map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map))
.getMap();
完全错误消息：
Full Error message:
java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.MapFragment.getMap()' on a null object reference
at com.collusion.serviceassistant.ReturnVisitDetails.onViewCreated(ReturnVisitDetails.java:39)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:904)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
at android.app.BackStackRecord.run(BackStackRecord.java:684)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1447)
at android.app.FragmentManagerImpl$1.run(FragmentManager.java:443)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
下面是我的片断code：
Here is my fragment code:
import android.app.Activity;
import android.app.Dialog;
import android.net.Uri;
import android.os.Bundle;
import android.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.MapView;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
public class ReturnVisitDetails extends Fragment {
static final LatLng HAMBURG = new LatLng(53.558, 9.927);
static final LatLng KIEL = new LatLng(53.551, 9.993);
private GoogleMap map;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_return_visit_add, container, false);
return rootView;
}
public void onViewCreated(View view, Bundle savedInstanceState)
{
// Get a handle to the Map Fragment
map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map))
.getMap();
Marker hamburg = map.addMarker(new MarkerOptions().position(HAMBURG)
.title("Hamburg"));
Marker kiel = map.addMarker(new MarkerOptions()
.position(KIEL)
.title("Kiel")
.snippet("Kiel is cool")
.icon(BitmapDescriptorFactory
.fromResource(R.drawable.ic_launcher)));
// Move the camera instantly to hamburg with a zoom of 15.
map.moveCamera(CameraUpdateFactory.newLatLngZoom(HAMBURG, 15));
// Zoom in, animating the camera.
map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null);
}
}
和我父母片段XML布局：
And my parent fragment XML layout:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.collusion.serviceassistant.ReturnVisitDetails"
android:background="#009688">
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.google.android.gms.maps.MapFragment" />
</RelativeLayout>
任何人都有一个想法，为什么在地图片段返回null？
Anyone have an idea why the map fragment is returning null?
编辑：所以现在我有这个code初始化图：
So now I have this code to initialize the map:
MapFragment mapFragment = new MapFragment();
FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
transaction.add(R.id.rl_map_container, mapFragment).commit();
map = mapFragment.getMap();
Marker hamburg = map.addMarker(new MarkerOptions().position(HAMBURG)
.title("Hamburg"));
Marker kiel = map.addMarker(new MarkerOptions()
.position(KIEL)
.title("Kiel")
.snippet("Kiel is cool")
.icon(BitmapDescriptorFactory
.fromResource(R.drawable.ic_launcher)));
// Move the camera instantly to hamburg with a zoom of 15.
map.moveCamera(CameraUpdateFactory.newLatLngZoom(HAMBURG, 15));
// Zoom in, animating the camera.
map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null);
和它仍然会返回一个空指针值
And it still returns a null pointer value
推荐答案
这个问题发生在我身上时，我试图端口我的Eclipse项目到Android Studio项目。
This issue happened to me when I tried to port my Eclipse project to Android Studio project.
java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.SupportMapFragment.getMap()' on a null object reference
我用它与一个片段活动是这样的：
I used it with a Fragment Activity like this:
((SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.mapToday)).getMap();
然而，问题是，前面我使用谷歌播放服务的特定版本（4.3.23）。
However, the problem was, earlier I was using a specific version of Google Play Services (4.3.23).
不过摇篮打造选择最新的版本（编译com.google.android.gms：玩-服务：+'）
But the Gradle build select the most recent version (compile 'com.google.android.gms:play-services:+')
我尝试了一些其他的特定版本一样（71年6月1日）。但还是给了零点例外。
I tried some other specific version like (6.1.71). But still gave null point exception.
我用同样的旧版本，因为我之前用和它的工作。
I used the same old version as I used before and it worked.
compile 'com.google.android.gms:play-services:4.3.23'
这对我的作品作为一种临时解决方案。然而，这将是一个问题，当我需要更新到 新戏服务库。
This works for me as a temporary solution. However, this will be a problem when I need to update to a new play services library.
看来，有没有具体的图库与此版本适用于摇篮建设 当我尝试这样的：
It seems that there is no specific map library with this version available for Gradle build when I try like this:
compile 'com.google.android.gms:play-services-maps:4.3.23'
这篇关于谷歌地图碎片返回null片段内的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
