我是大学的法国学生，我必须制作一个使用谷歌地图的Android应用程序。不幸的是，当我尝试在手机上使用我的应用程序时遇到问题：当我尝试使用GoogleMap访问该部件时，应用程序将关闭。 感谢您的帮助。
package darknesshadow.localisation;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.widget.Toast;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.MapFragment;
public class MapsActivity extends AppCompatActivity implements LocationListener{
//Declaration des Variables
private GoogleMap gMap;
private LocationManager locationManager;
private Marker marker;
//Méthodes
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
gMap = ((MapFragment)getFragmentManager().findFragmentById(R.id.map)).getMap();
marker = gMap.addMarker(new MarkerOptions().title("Vous êtes ici").position(new LatLng(0, 0)));
}
@Override
protected void onResume() {
super.onResume();
locationManager = (LocationManager) this.getSystemService(LOCATION_SERVICE);
if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
activationGPS();
}
}
@Override
protected void onPause() {
super.onPause();
desactivationGPS();
}
public void activationGPS() {
if ((ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED)
&& (ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)) {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000, 10, this);
}
}
public void desactivationGPS() {
if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
&& ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
locationManager.removeUpdates(this);
}
}
@Override
public void onLocationChanged(final Location location) {
final StringBuilder msg = new StringBuilder("lat : ");
msg.append(location.getLatitude());
msg.append("; lng : ");
msg.append(location.getLongitude());
Toast.makeText(this, msg.toString(), Toast.LENGTH_SHORT).show();
final LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
gMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 15));
marker.setPosition(latLng);
}
@Override
public void onProviderDisabled(final String provider) {
if ("gps".equals(provider)) {
desactivationGPS();
}
}
@Override
public void onProviderEnabled(final String provider) {
if ("gps".equals(provider)) {
activationGPS();
}
}
@Override
public void onStatusChanged(final String provider, final int status, final Bundle extras) {
}
}
The Manifest：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="darknesshadow.localisation"
android:versionCode="1"
android:versionName="1.0" >
<uses-feature
android:glEsVersion="0x00020000"
android:required="true"
/>
<uses-sdk
android:minSdkVersion="9"
android:targetSdkVersion="17" />
<uses-feature
android:glEsVersion="0x00020000"
android:required="true" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses_permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<meta-data
android:name="com.google.android.geo.API_KEY"
android:value="@string/google_maps_key" />
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version"
/>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".NouveauTrajet"
android:label="Nouveau Trajet">
</activity>
<activity
android:name=".Tab"
android:label="Tab">
</activity>
<activity
android:name=".OngletAcceuil"
android:label="OngletAcceuil">
</activity>
<activity
android:name=".Onglet1"
android:label="Onglet1">
</activity>
<activity
android:name=".Onglet2"
android:label="Onglet2">
</activity>
<activity
android:name=".Onglet3"
android:label="Onglet3">
</activity>
<activity
android:name=".Onglet4"
android:label="Onglet4">
</activity>
<activity
android:name=".MapsActivity"
android:label="@string/title_activity_maps">
</activity>
</application>
</manifest>
XML：
fragment
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:map="http://schemas.android.com/apk/res-auto"
/>
Android监视器：
03-12 19:01:38.881 17146-17146/darknesshadow.localisation E/AndroidRuntime: FATAL EXCEPTION: main
Process: darknesshadow.localisation, PID: 17146
java.lang.RuntimeException: Unable to start activity ComponentInfo{darknesshadow.localisation/darknesshadow.localisation.MapsActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2187)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2236)
at android.app.ActivityThread.access$800(ActivityThread.java:138)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5095)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at darknesshadow.localisation.MapsActivity.onCreate(MapsActivity.java:33)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2151)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2236)
at android.app.ActivityThread.access$800(ActivityThread.java:138)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5095)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：0)
您在片段管理器或地图片段上都有一个空指针。当您使用AppCompatActivity时，请尝试使用getSupportFragmentManager（）而不是getFragmentManager（）。
答案 1 :(得分：0)
在布局文件中，您指的是SupportMapFragment，但在活动中您使用的是MapFragment， 将布局XML文件更改为MapFragment