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我正在尝试使用 Service 让 GPS 位置在后台运行。当我单击“开始”按钮时，GPS 位置每隔 X 时间间隔发送到屏幕，并在单击“停止”按钮时停止。我第一次运行项目时它工作了，但是一旦我关闭应用程序并再次打开它，它就不再工作了。我已经清理了项目并再次运行它，但没有显示任何内容。我错过了什么？

这是活动代码

import android.Manifest;
import android.app.Dialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.ActivityInfo;
import android.content.pm.PackageManager;
import android.location.Location;

import android.location.LocationManager;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.common.GoogleApiAvailability;
import com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks;
import com.google.android.gms.common.api.GoogleApiClient.OnConnectionFailedListener;
import com.google.android.gms.location.FusedLocationProviderApi;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.ConnectionResult;

import java.text.DateFormat;
import java.util.Date;

public class testLocationActivity extends AppCompatActivity
{

    protected LocationHelper locationHelper;

    protected TextView textView;
    protected Button btn_start;
    protected Button btn_stop;
    protected BroadcastReceiver broadcastReceiver;

    @Override
    protected void onResume() {
        super.onResume();

        if(broadcastReceiver == null)
        {
            broadcastReceiver = new BroadcastReceiver() {
                @Override
                public void onReceive(Context context, Intent intent) {

                    textView.append("\n" + intent.getExtras().get("coordinates"));

                }
            };
        }
        registerReceiver(broadcastReceiver, new IntentFilter("location_update"));
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        if(broadcastReceiver != null)
        {
            unregisterReceiver(broadcastReceiver);
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test_location);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);

        setSupportActionBar(toolbar);
        getSupportActionBar().setTitle("Test Location");
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

            this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

        textView = (TextView) findViewById(R.id.textView);
        btn_start = (Button) findViewById(R.id.button);
        btn_stop = (Button) findViewById(R.id.button2);


        if(!runtime_permissions())
        {
            enable_buttons();
        }

    }

    private void enable_buttons()
    {
        btn_start.setOnClickListener(new View.OnClickListener()
        {

            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), LocationHelper.class);
                startService(intent);
            }
        });

        btn_stop.setOnClickListener(new View.OnClickListener()
        {

            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), LocationHelper.class);
                stopService(intent);
            }
        });
    }

    private boolean runtime_permissions()
    {
        if(Build.VERSION.SDK_INT >= 23 && ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
        {
            requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION}, 100);
            return true;
        }

        return true;


    }

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

        if(requestCode == 100)
        {
            if(grantResults[0] == PackageManager.PERMISSION_GRANTED && grantResults[1] == PackageManager.PERMISSION_GRANTED)
            {
                enable_buttons();
            }
            else
            {
                runtime_permissions();
            }
        }
    }
}

这是扩展 Service 的 LocationHelper.java 类

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.support.annotation.Nullable;
import android.util.Log;

import android.location.LocationListener;

import com.firebase.client.Firebase;
import com.google.firebase.auth.FirebaseAuth;

public class LocationHelper extends Service
{

    private LocationListener listener;
    private LocationManager locationManager;

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate()
    {
        listener = new LocationListener() {

            @Override
            public void onLocationChanged(Location location)
            {
                Intent intent = new Intent("location_update");

                intent.putExtra("coordinates", location.getLongitude()+ " " + location.getLatitude());
                sendBroadcast(intent);

            }

            @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);
                intent.setFlags(intent.FLAG_ACTIVITY_NEW_TASK);

                startActivity(intent);
            }
        };

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

        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,3000,0, listener);

            //locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,3000,0, listener);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();

        if(locationManager != null)
        {
            locationManager.removeUpdates(listener);
        }
    }
}

任何帮助或指针表示赞赏！

4

1 回答 1

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对于那些感兴趣的人，我发现了错误。我必须在 runtime_permissions 函数中返回 true。当我将第二次返回更改为返回 false 时，一切正常！

于 2017-03-26T07:41:30.850 回答