无法使用 LocationListener android studio 2.3 在日志中显示当前位置

Question

我正在尝试获取用户的当前位置并将其显示在日志中

这是我的主要活动 Java 代码

import android.Manifest;
import android.content.Context;
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.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

LocationManager locationManager;
LocationListener locationListener;

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

    locationManager = (LocationManager)this.getSystemService(Context.LOCATION_SERVICE);

    locationListener = new LocationListener() {
        @Override
        public void onLocationChanged(Location location) {

            Log.i("Location",location.toString());
        }

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

        }

        @Override
        public void onProviderEnabled(String provider) {

        }

        @Override
        public void onProviderDisabled(String provider) {

        }
    };

    //If the device is running version older than Marshmallow

    if(Build.VERSION.SDK_INT<23)
    {
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
    }

    else
    {
        //Checking if it has permission access
        if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED)
        {
            //ask for permission

            ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_FINE_LOCATION},1);


        }
        else
        {
            //we have permission

            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
        }
    }
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);

    if(ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED)
    {
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
    }
}

}

但我的日志中没有看到销售标签，以下是相应的日志：

Here are My Logs

我是 Android 地图的新手，所以我不太确定我的代码哪里出错了。

Answer 1

首先你需要移动LocationListener到onCreate()之外：

public class MainActivity extends AppCompatActivity {

LocationManager locationManager;
LocationListener locationListener;

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

   if(Build.VERSION.SDK_INT<23)
    {
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
    }

    else
    {
        //Checking if it has permission access
        if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED)
        {
            //ask for permission

            ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_FINE_LOCATION},1);


        }
        else
        {
            //we have permission

            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
        }
    }
}


  locationListener = new LocationListener() {
        @Override
        public void onLocationChanged(Location location) {

            Log.i("Location",location.toString());
        }

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

        }

        @Override
        public void onProviderEnabled(String provider) {

        }

        @Override
        public void onProviderDisabled(String provider) {

        }
    };

    .....
}

然后，修改onRequestPermissionResult()如下：

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);

    switch (requestCode) {
        case 1: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);

            } else {
                Toast.makeText(getApplicationContext(), "Please provide permission.", Toast.LENGTH_LONG).show();
            }
            break;
        }
    }
}