java如何让doInBackground()等待AyncTask类中的另一个函数?
我有一个自定义的AsyncTask类,它检查设备是否已授予位置权限,然后获取最后一个已知位置。如果没有权限,它会先向用户请求权限。所以在我的doInBackground函数中,我需要调用mGoogleApiClient。connect()这将触发onConnected函数。可以看出,doInBackground需要等待onConnected,否则它将返回null对象lastKnownLocation。我的问题是如何让doInBackground等待onConnected
public class GetLocationTask extends AsyncTask<Void, Void, Location> implements GoogleApiClient.ConnectionCallbacks
, GoogleApiClient.OnConnectionFailedListener {
private Context context;
private Activity activity;
private GoogleApiClient mGoogleApiClient;
private Location lastKnownLocation = null; //In case the users reject location permission request, we might initialize the location to something interesting
public AsyncResponseForLocation delegate = null;
private static final int MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1;
public GetLocationTask(Activity activity, Context context) {
this.activity = activity;
this.context = context;
}
@Override
protected Location doInBackground(Void... params) {
if (mGoogleApiClient == null) {
mGoogleApiClient = new GoogleApiClient.Builder(context)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
mGoogleApiClient.connect();
return lastKnownLocation;
}
@Override
public void onConnected(@Nullable Bundle bundle) {
if (ActivityCompat.checkSelfPermission(context,
安卓.Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED
&& ActivityCompat.checkSelfPermission(context,
安卓.Manifest.permission.ACCESS_COARSE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(activity,
new String[]{安卓.Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);
}
lastKnownLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
@Override
protected void onPostExecute(Location location) {
delegate.processFinish(location);
}
public interface AsyncResponseForLocation {
void processFinish(Location location);}
# 1 楼答案
你的流量不正确,在你尝试获取位置检查之前,如果你有权限
当用户需要批准您的权限请求时,您必须处理onRequestPermissionsResult方法:
# 2 楼答案
执行一个Timertask,每5秒运行一次,以检查条件是否已连接()
试试下面的代码