不能读取GPS读数

问题描述

我想在我的应用程序中使用GPS。但是当我试图检索GPS读数，如代码中所示，Android工作室给了我提到的错误

despit将所有必需的权限添加到清单文件

p>

代码：

  LocationManager lm =（ LocationManager）ctx.getSystemService（Context.LOCATION_SERVICE）; 
 LocationListener ll = new LocationListener（）{
 @Override 
 public void onLocationChanged（Location location）{
 Log.w（TAG，onLocationChanged）; 
 
 $ b @Override 
 public void onStatusChanged（String provider，int status，Bundle extras）{
 Log.w（TAG，onStatusChanged）; 
 
 
 $ b @Override 
 public void onProviderEnabled（String provider）{
 Log.w（TAG，onProviderEnabled）; 
} 
 
 @Override 
 public void onProviderDisabled（String provider）{
 Log.w（TAG，onProviderDisabled）; 
} 
}; 
 lm.requestLocationUpdates（LocationManager.NETWORK_PROVIDER，0，0，ll）; //错误在这一行
  

permission.ACCESS_FINE_LOCATION）== PackageManager.PERMISSION_GRANTED&&& ContextCompat.checkSelfPermission（this，Manifest.permission.ACCESS_COARSE_LOCATION）== PackageManager.PERMISSION_GRANTED）{

}

您还应该写入一个else语句请求代码，如果用户没有得到它，它将向用户请求许可。

以下是一个很好的请求权限方法：

  public void requestPermissions（List< String>权限，ActivityCompat.OnRequestPermissionsResultCallback onRequestPermissionsResultCallback）{
 String [] params = permissions.toArray（new String [permissions.size（）]）; 
 requestPermissions（params，onRequestPermissionsResultCallback）; 
 
 $ / code> 

在您的情况下，您必须将位置权限传递给您使用此方法：



 私人列表< String> getRequiredLocationPermissions（）{
 String accessCoarsePermission = android.Manifest.permission.ACCESS_COARSE_LOCATION; 
 String accessFineLocationPermission = android.Manifest.permission.ACCESS_FINE_LOCATION; 
 int hasCoarsePermission = ContextCompat.checkSelfPermission（getActivity（），accessCoarsePermission）; 
 int hasFineLocationPermission = ContextCompat.checkSelfPermission（getActivity（），accessFineLocationPermission）; 
列表< String> permissions = new ArrayList<>（）; 
 if（hasCoarsePermission！= PackageManager.PERMISSION_GRANTED）{
 permissions.add（accessCoarsePermission）; 
 
 if（hasFineLocationPermission！= PackageManager.PERMISSION_GRANTED）{
 permissions.add（accessFineLocationPermission）; 
} 
返回权限; 
} 
  




i want to use GPS in my App. but when i tried to retrieve GPS readings as shown belwo in the code, Android studio gave me the belwo mentioned error

despit all the required permissions are added to manifest file

code:

LocationManager lm = (LocationManager) ctx.getSystemService(Context.LOCATION_SERVICE);
    LocationListener ll = new LocationListener() {
        @Override
        public void onLocationChanged(Location location) {
            Log.w(TAG, "onLocationChanged");
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            Log.w(TAG, "onStatusChanged");

        }

        @Override
        public void onProviderEnabled(String provider) {
            Log.w(TAG, "onProviderEnabled");
        }

        @Override
        public void onProviderDisabled(String provider) {
            Log.w(TAG, "onProviderDisabled");
        }
    };
    lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, ll);//error at this line

解决方案

This is due to in Marshmallow (Android version 6.0) Users can choose to turn off permissions. Simply wrap this check to see if the permission is enabled before your location code.

if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED && ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {

}

You should also write in an else statement request code which will request the permission from the user if they haven't got it.

Here's a nice request permissions method:

public void requestPermissions(List<String> permissions, ActivityCompat.OnRequestPermissionsResultCallback onRequestPermissionsResultCallback) {
    String[] params = permissions.toArray(new String[permissions.size()]);
    requestPermissions(params, onRequestPermissionsResultCallback);
}

In your case you will have to pass it the Location permissions which you can get with this method:

private List<String> getRequiredLocationPermissions() {
    String accessCoarsePermission = android.Manifest.permission.ACCESS_COARSE_LOCATION;
    String accessFineLocationPermission = android.Manifest.permission.ACCESS_FINE_LOCATION;
    int hasCoarsePermission = ContextCompat.checkSelfPermission(getActivity(), accessCoarsePermission);
    int hasFineLocationPermission = ContextCompat.checkSelfPermission(getActivity(), accessFineLocationPermission);
    List<String> permissions = new ArrayList<>();
    if (hasCoarsePermission != PackageManager.PERMISSION_GRANTED) {
        permissions.add(accessCoarsePermission);
    }
    if (hasFineLocationPermission != PackageManager.PERMISSION_GRANTED) {
        permissions.add(accessFineLocationPermission);
    }
    return permissions;
}

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