android gps应用程序仅在第一次工作

Question

I am trying to make a GPS android application which will use GPS and wify connection to find the location and show the coordinates when a button is clicked.

When I install and run it first time, it works fine; asks for permission and append the coordinates. But when I close it and run it again (disabling my location) it just shows the application interface and nothing happens when the button is clicked.

I am very new in programming and for coding I mostly used online references. Can anyone please suggest me what am I missing here?

 import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private Button button;
    private TextView textView;
    private LocationManager locationManager;
    private LocationListener locationListener;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        button = (Button) findViewById(R.id.button);
        textView = (TextView) findViewById(R.id.textView);

        locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
        locationListener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                textView.append ("\n" + location.getLatitude() + ",   " + location.getLongitude());
            }

            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {

            }

            @Override
            public void onProviderEnabled(String provider) {

            }

            @Override
            public void onProviderDisabled(String provider) {
                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                startActivity(intent);
            }
        };

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
               requestPermissions(new String[]{
                       Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION,
                       Manifest.permission.INTERNET
               },10);
                return;
            }
        } else {
            configureButton();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
       switch (requestCode){
           case 10:
               if(grantResults.length>0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
                   configureButton();
               return;
       }
    }

    private void configureButton() {
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                locationManager.requestLocationUpdates("gps", 5000, 0, locationListener);
            }
        });

    }
}

Answer 1

According to the docs requestPermission

Your MainActivity has to implement ActivityCompat.OnRequestPermissionsResultCallback and register the callback to requestPermission

requestPermissions(this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION,Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.INTERNET}, 10);

Answer 2

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
    if (   ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)   != PackageManager.PERMISSION_GRANTED
        && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        requestPermissions(new String[]{
                Manifest.permission.ACCESS_COARSE_LOCATION,
                Manifest.permission.ACCESS_FINE_LOCATION,
                Manifest.permission.INTERNET
            },10);
        return;
    }
    else {
        configureButton();//add this extra else to your code and it works.
    }
} else {
    configureButton();
}