问题描述
我使用GoogleApiClient获取用户位置。我创建了一个单例类来获取用户位置。这里是这个类：
public class LocationUtils {
private static LocationUtils locationUtils;
私有GoogleApiClient googleApiClient;
public static LocationUtils getInstance（）{
if（locationUtils == null）
locationUtils = new LocationUtils（）;
返回locationUtils;
private LocationUtils（）{}
public Location getLocation（Context context）{
final Location [] location = {空值};
googleApiClient = new GoogleApiClient.Builder（App.getContext（））
.addConnectionCallbacks（new GoogleApiClient.ConnectionCallbacks（）{
@Override
public void onConnected（Bundle Bundle）{
if（ContextCompat.checkSelfPermission（App.getContext（），Manifest.permission.ACCESS_FINE_LOCATION）== PackageManager.PERMISSION_GRANTED）
location [0] = LocationServices.FusedLocationApi.getLastLocation（googleApiClient）;
googleApiClient.disconnect（）;
}
@Override
public void onConnectionSuspended（int i）{
}
}）
.addOnConnectionFailedListener（new GoogleApiClient.OnConnectionFailedListener（）{
@Override
public void onConnectionF ailed（ConnectionResult connectionResult）{
}
}）
.addApi（LocationServices.API）
.build（）;
googleApiClient.connect（）;
return location [0];
}
}
我想通过LocationUtils.getInstance（）。getLocation（context）获取用户位置。当我调用getLocation（）方法时，它应该连接到GoogleApiClient，返回用户位置并断开连接到每个调用的GoogleApiClient。但是当我调用该方法时，它将返回null。主线程不会等待onConnected（）方法，并将位置对象返回为null。它如何等待onConnect（）方法？或者我怎么能在onConnected（）中返回Location对象？
已解决根据Tim Castelijns的回答
首先我创建了一个接口：
public interface LocationCallbackInterface {
void onComplete（Location location）;
}
然后在getLocationMethod（）中使用它：
public void getLocation（Context context，final LocationCallbackInterface callback）{
final Location [] location = {空值};
googleApiClient = new GoogleApiClient.Builder（App.getContext（））
.addConnectionCallbacks（new GoogleApiClient.ConnectionCallbacks（）{
@Override
public void onConnected（Bundle Bundle）{
if（ContextCompat.checkSelfPermission（App.getContext（），Manifest.permission.ACCESS_FINE_LOCATION）== PackageManager.PERMISSION_GRANTED）{
location [0] = LocationServices.FusedLocationApi.getLastLocation（googleApiClient）;
//Toast.makeText（App.getContext（），location came：+ location [0] .toString（），Toast.LENGTH_LONG）.show（）;
callback.onComplete（location [ 0]）;
}
googleApiClient.disconnect（）;
}
@Override
public void onConnectionSuspended（int i）{
}
}）
.addOnConnectionFailedListener（新的GoogleApiClient.OnConnect ctionFailedListener（）{
@Override
public void onConnectionFailed（ConnectionResult connectionResult）{
$ b}）
.addApi（LocationServices.API）
.build（）;
googleApiClient.connect（）;
}
然后调用该方法一个活动：
$ $ p $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ b @Override
public void onComplete（Location location）{
if（location！= null）{
Toast.makeText（getActivity（），location：+ location.toString（） ，Toast.LENGTH_SHORT）.show（）;
initCamera（location）;
} else
Toast.makeText（getActivity（），location is null，Toast.LENGTH_SHORT）.show（ ）;
}
}）;
由于位置是异步获取的，因此您应该使用回调返回的位置，否则您的返回值将始终为空，因为googleApiClient尚未完成。
定义一个类似这样的接口
public interface LocationCallback {
void onComplete（Location location）;
更改
public Location getLocation（Context context）
to
public Location getLocation（Context context，LocationCallback callback）
并且像这样称呼它
LocationUtils.getLocation（context，new LocationCallback（）{
@Override
onComplete（位置位置）{
//当调用这个函数时，您将获得一个位置
}
}）;
I am using GoogleApiClient to get user location. I created a singleton class to get user location. Here is that class:
public class LocationUtils {
private static LocationUtils locationUtils;
private GoogleApiClient googleApiClient;
public static LocationUtils getInstance() {
if(locationUtils == null)
locationUtils = new LocationUtils();
return locationUtils;
}
private LocationUtils() {}
public Location getLocation(Context context){
final Location[] location = {null};
googleApiClient = new GoogleApiClient.Builder(App.getContext())
.addConnectionCallbacks(new GoogleApiClient.ConnectionCallbacks() {
@Override
public void onConnected(Bundle bundle) {
if(ContextCompat.checkSelfPermission(App.getContext(), Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED)
location[0] = LocationServices.FusedLocationApi.getLastLocation(googleApiClient );
googleApiClient.disconnect();
}
@Override
public void onConnectionSuspended(int i) {
}
})
.addOnConnectionFailedListener(new GoogleApiClient.OnConnectionFailedListener() {
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
})
.addApi( LocationServices.API )
.build();
googleApiClient.connect();
return location[0];
}
}
I want to get user location with LocationUtils.getInstance().getLocation(context) . When i call getLocation() method, it should connect to GoogleApiClient, return user location and disconnect to GoogleApiClient for every call. But when i call that method, it returns null. The main thread does not wait for onConnected() method and returns location object as null. How can it waits for onConnect() method ? OR how can i return Location object in onConnected() ?
SOLVED according to Tim Castelijns's answer
First i created an interface:
public interface LocationCallbackInterface {
void onComplete(Location location);
}
then used it in getLocationMethod() :
public void getLocation(Context context, final LocationCallbackInterface callback){
final Location[] location = {null};
googleApiClient = new GoogleApiClient.Builder(App.getContext())
.addConnectionCallbacks(new GoogleApiClient.ConnectionCallbacks() {
@Override
public void onConnected(Bundle bundle) {
if(ContextCompat.checkSelfPermission(App.getContext(), Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
location[0] = LocationServices.FusedLocationApi.getLastLocation(googleApiClient);
//Toast.makeText(App.getContext(), "location came :" + location[0].toString(), Toast.LENGTH_LONG).show();
callback.onComplete(location[0]);
}
googleApiClient.disconnect();
}
@Override
public void onConnectionSuspended(int i) {
}
})
.addOnConnectionFailedListener(new GoogleApiClient.OnConnectionFailedListener() {
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
})
.addApi( LocationServices.API )
.build();
googleApiClient.connect();
}
then called that method in an activity:
LocationUtils.getInstance().getLocation(getActivity(), new LocationCallbackInterface() {
@Override
public void onComplete(Location location) {
if (location != null) {
Toast.makeText(getActivity(), "location :" + location.toString(), Toast.LENGTH_SHORT).show();
initCamera(location);
} else
Toast.makeText(getActivity(), "location is null", Toast.LENGTH_SHORT).show();
}
});
Since the location is acquired asynchronously, you should use a callback to return the location, otherwise your return value will always be null because the googleApiClient is not done yet.
Define an interface like this
public interface LocationCallback {
void onComplete(Location location);
}
Change
public Location getLocation(Context context)
to
public Location getLocation(Context context, LocationCallback callback)
and call it like this
LocationUtils.getLocation(context, new LocationCallback() {
@Override
onComplete(Location location) {
// when this is called, you will have a location.
}
});
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