位置仅在应用程序失焦时更新 TextView

Question

出于某种原因，它仅在应用程序点击 onPause 时更新文本视图，例如当我点击主页按钮或多任务按钮时。谁能帮我弄清楚这是为什么？

MainActivity.java:

import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private String lat, lon;
    private TextView longTextView, latTextView;
    LocationService locationService = new LocationService(this);
    private Intent intentService;
    private PendingIntent pendingIntent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        latTextView = (TextView) findViewById(R.id.latitude_textview);
        longTextView = (TextView) findViewById(R.id.longitude_textview);  
    }

    @Override
    protected void onStart() {
        super.onStart();
        locationService.buildGoogleApiClient();
        locationService.apiConnect();

        if (latTextView != null && longTextView != null) {
            latTextView.setText( locationService.getLat());
            longTextView.setText( locationService.getLon());
            Toast.makeText(getApplicationContext(), " Actually got location", Toast.LENGTH_SHORT)
                    .show();
        } else {
            Toast.makeText(getApplicationContext(), "The shit was null fam", Toast.LENGTH_LONG)
                    .show();
        }
    }

    @Override
    protected void onStop() {
        super.onStop();
        locationService.apiDisconnect();   
    }  
}

LocationService.java:

import android.Manifest;
import android.app.Activity;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Location;
import android.os.Bundle;
import android.os.IBinder;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.util.Log;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
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 static com.google.android.gms.wearable.DataMap.TAG;

public class LocationService extends Service implements GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener, LocationListener {

    // =============================================================  Variables

    Context context;
    Location mLastLocation;
    private GoogleApiClient mGoogleApiClient;
    private LocationRequest mLocationRequest;
    private String lat, lon;
    final static String[] LOCATION_PERMISSIONS = {Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION};
    public static final long UPDATE_INTERVAL_IN_MILLISECONDS = 10000;
    public static final long UPDATE_FASTEST_INTERVAL_IN_MILLISECONDS = UPDATE_INTERVAL_IN_MILLISECONDS / 2;
    public static boolean isEnded = false;
    public static Boolean requestingLocationUpdates;
    protected String lastUpdateTime;

    final int GOOGLEAPI_REQUEST_CODE = 24;
    private FusedLocationProviderApi fusedLocationProviderApi = LocationServices.FusedLocationApi;    

    // =============================================================  Constructor    

    public LocationService(Context context) {
        this.context = context;
    }

    // =============================================================  Getters / Setters    

    public String getLon() {
        return lon;
    }

    public void setLon(String lon) {
        this.lon = lon;
    }

    public String getLat() {
        return lat;
    }

    public void setLat(String lat) {
        this.lat = lat;
    }    

    // ============================================================= Methods
    synchronized void buildGoogleApiClient() {
        mGoogleApiClient = new GoogleApiClient.Builder(context)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }

    public void apiConnect() {
        mGoogleApiClient.connect();
    }

    public void apiDisconnect() {
        mGoogleApiClient.disconnect();
    }

    void updateUI() {    
    }

    // ============================================================= Implemented Location Methods
    @Override
    public void onLocationChanged(Location location) {
        setLat(String.valueOf(location.getLatitude()));
        setLon(String.valueOf(location.getLongitude()));
    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
        Log.i(TAG, "Connection failed: ConnectionResult.getErrorCode() = " + connectionResult.getErrorCode());
    }

    @Override
    public void onConnected(@Nullable Bundle bundle) {
        mLocationRequest = LocationRequest.create();
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
        mLocationRequest.setInterval(UPDATE_INTERVAL_IN_MILLISECONDS); // Sets Location to update every second
        mLocationRequest.setFastestInterval(UPDATE_FASTEST_INTERVAL_IN_MILLISECONDS); // The fastest location can update is every half-second

        startLocationUpdates();

        // TODO come back to this to see whats up
       /* mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
                mGoogleApiClient);*/
        if (mLastLocation != null) {
            setLat(String.valueOf(mLastLocation.getLatitude()));
            setLon(String.valueOf(mLastLocation.getLongitude()));    
        }
    }

    @Override
    public void onConnectionSuspended(int i) {    
    }

    protected void startLocationUpdates() {
        /*if (!requestingLocationUpdates) {
            requestingLocationUpdates = true;*/

            if (ActivityCompat.checkSelfPermission(context, android.Manifest.permission.ACCESS_FINE_LOCATION)
                    != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(context, android.Manifest.permission.ACCESS_COARSE_LOCATION)
                    != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions((Activity) context, LOCATION_PERMISSIONS, GOOGLEAPI_REQUEST_CODE);

            } else {
                LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
            }
            Log.i(TAG, " startLocationUpdates===");
            isEnded = true;
        //}
    }    

    // ============================================================= Implemented Service Methods

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

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // Within {@code onPause()}, we pause location updates, but leave the
        // connection to GoogleApiClient intact.  Here, we resume receiving
        // location updates if the user has requested them.
        Log.d("LOC", "Service init...");
        isEnded = false;
        requestingLocationUpdates = false;
        lastUpdateTime = "";
        buildGoogleApiClient();
        if (mGoogleApiClient.isConnected() && requestingLocationUpdates) {
            startLocationUpdates();
        }
        return Service.START_REDELIVER_INTENT;
    }
}

Answer 1

您没有在 textview 中更新位置的原因是您的代码无法让服务与 activity 通信。

如果您只想在 activity 处于前台时获取位置，请不要使用 Service，请查看此 google's example 以获取位置并使用融合位置提供程序更新 TextView。

我不确定你为什么要使用 Service.Use 服务仅当你想要 连续获取位置时，即使应用程序是运行背景。为此，请使用提到的任何一种方法 here to inform the activity that a new location has been obtained.LocalBroadcast would be your best bet. Anyway explore the best possible solution that suits your usecase in the previous link.

位置仅在应用程序失焦时更新 TextView

Location only updating TextView when app is out of focus

android

service

google-api-client

fusedlocationproviderapi