FusedLocationProviderClient何时以及如何停止Looper？

Question

我曾经使用过FusedLocationApi,直到我得知它已被弃用(参见下面的参考资料).实施起来很简单.正如文档所说,您需要将其与GoogleApiClient结合使用

LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient,
                        locationRequest, this);

我最近更改为FusedLocationProviderClient(参见下面的参考资料)根据教程,我能够成功地使FusedLocationProviderClient工作

教程:https://github.com/codepath/android_guides/wiki/Retrieving-Location-with-LocationServices-API

// new Google API SDK v11 uses getFusedLocationProviderClient(this)
getFusedLocationProviderClient(this).requestLocationUpdates(mLocationRequest, new LocationCallback() {
      @Override
      public void onLocationResult(LocationResult locationResult) {
         // do work here
         onLocationChanged(locationResult.getLastLocation();
      }
    },
    Looper.myLooper());

我遇到的问题是Looper线程.即使应用程序在后台运行,Looper线程也会继续运行.我想在应用程序在后台时暂停位置更新,然后在应用程序位于前台时恢复位置更新.我怎样才能做到这一点？

参考文献:

1. https://developers.google.com/android/reference/com/google/android/gms/location/FusedLocationProviderApi
2. https://developers.google.com/android/reference/com/google/android/gms/location/FusedLocationProviderClient

Answer 1

你只需要调用mFusedLocationClient.removeLocationUpdates(mLocationCallback)在onPause()你的活动.但是,它还有一点不止于此.

在主活动中使用FusedLocationProviderClient,GoogleApiClient和LocationRequest的成员变量:

import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationCallback;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationResult;

public class MainActivity extends AppCompatActivity
        GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener {

    FusedLocationProviderClient mFusedLocationClient;
    LocationRequest mLocationRequest;

    //..........

也为LocationCallback使用成员变量:

LocationCallback mLocationCallback = new LocationCallback(){
    @Override
    public void onLocationResult(LocationResult locationResult) {
        for (Location location : locationResult.getLocations()) {
            Log.i("MainActivity", "Location: " + location.getLatitude() + " " + location.getLongitude());

        }
    };

};

然后,分配mFusedLocationClient在onCreate():

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

    mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
    requestLocationUpdates();

    //...............
}

然后onResume(),如果设置了GoogleApiClient和FusedLocationProviderClient,则使用它们.否则,这是第一次启动Activity,所以连接GoogleApiClient:

@Override
public void onResume() {
    if (mFusedLocationClient != null) {
        requestLocationUpdates();
    }
}

public void requestLocationUpdates() {
    mLocationRequest = new LocationRequest();
    mLocationRequest.setInterval(120000); // two minute interval
    mLocationRequest.setFastestInterval(120000);
    mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
    if (ContextCompat.checkSelfPermission(this,
            Manifest.permission.ACCESS_FINE_LOCATION)
            == PackageManager.PERMISSION_GRANTED) {
        mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, Looper.myLooper());
    }
}

最后,在onPause(),致电removeLocationUpdates():

@Override
public void onPause() {
    super.onPause();
    if (mFusedLocationClient != null) {
        mFusedLocationClient.removeLocationUpdates(mLocationCallback);
    }
}