24

I have a bunch of people reporting an error that I cannot reproduce. When trying to open a MapView it's reporting that the getBestProvider is returning null and I know that means that that no provider is found that fulfills my criteria which is ACCURACY_COARSE so if there is no GPS then it should fall back on either network or passive but it obviously doesn't on those user devices. What would that even mean then that GPS is off and there is no network connection?

I tried turning GPS off and putting the phone into airplane mode to try to reproduce the problem but still I was able to open the mapview without a force close so I don't know how to handle this problem.

locationManager = (LocationManager) this.getSystemService(LOCATION_SERVICE);
geocoder = new Geocoder(this);

Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_COARSE);
List<String> lProviders = locationManager.getProviders(false);
for(int i=0; i<lProviders.size(); i++){
    Log.d("LocationActivity", lProviders.get(i));
}
String provider = locationManager.getBestProvider(criteria, true); // null

long minTime = 60000;
float minDistance = 5;

locationManager.requestLocationUpdates(provider, minTime, minDistance, this);

error

java.lang.RuntimeException: Unable to start activity ComponentInfo{ecm2.android/ecm2.android.LocationActivity}: 
java.lang.IllegalArgumentException: provider==null
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
at android.app.ActivityThread.access$2300(ActivityThread.java:125)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4627)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.IllegalArgumentException: provider==null
at android.location.LocationManager.requestLocationUpdates(LocationManager.java:625)
at ecm2.android.LocationActivity.onCreate(LocationActivity.java:142)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
4

2 回答 2

24

在您的呼叫中，getBestProvider()您只要求启用提供程序（这是您设置为的方法调用中的第二个参数true）。如果用户禁用了所有提供程序，您将获得null.

在任何情况下，您都需要能够处理没有可用提供程序的情况，因此您需要检查null并告诉用户他没有启用任何位置。

于 2012-05-21T16:01:48.637 回答
6

androidManifest.xml

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

MapsActivity.java

 @Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    if (permissions.length == 1 &&
            permissions[0] == android.Manifest.permission.ACCESS_FINE_LOCATION &&
            grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    ActivityCompat#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for ActivityCompat#requestPermissions for more details.
            return;
        }
        mMap.setMyLocationEnabled(true);
    } else {
        // Permission was denied. Display an error message.
    }
}

MapsActivity.java/onCreate()

if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION)
            == PackageManager.PERMISSION_GRANTED) {
        mMap.setMyLocationEnabled(true);
    } else {
        ActivityCompat.requestPermissions(this,new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, 1);
    }

这对我有用；

于 2016-08-02T19:40:12.290 回答