我发送IntentService
来自MainActivity
的电话到MapClass
的班级。 MapClass
有一个名为MapClassInner
的内部类,它计算用户的当前坐标。但是,外部类包含onHandleIntent
方法,该方法最终将使用广播将坐标发送回MainActivity
。我的问题是 - 如何访问MapClassInner
的内部变量?我很确定答案很简单,但我已经连续工作了2个小时,所以我的想法变得有点不对劲。
这里是代码(MapClass.java):
import android.app.IntentService;
import android.content.Intent;
import android.location.Location;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
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.LocationServices;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.model.LatLng;
import org.greenrobot.eventbus.EventBus;
import org.greenrobot.eventbus.Subscribe;
import meetup.be2015.gcm_meetup.MainActivity.MyLocationReceiver;
public class MapClass extends IntentService {
public static final String REQUEST_STRING = "myRequest";
public static final String RESPONSE_LAT = "lat";
public static final String RESPONSE_LNG = "lng";
public GoogleMap map;
public MapClass() {
super("MapClass");
}
private class MapClassInner extends AppCompatActivity implements OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener {
private GoogleApiClient mGoogleApiClient;
private GoogleMap mgoogleMap;
private LatLng latLng;
private GoogleApiClient client;
public MapClassInner(GoogleMap map){
this.mgoogleMap = map;
}
@Override
public void onMapReady(GoogleMap googleMap) {
Log.d("ON_MAP_READY","In OnMapReady");
mgoogleMap = googleMap;
mgoogleMap.setMyLocationEnabled(true); //Sets location to current position
buildGoogleApiClient();
mGoogleApiClient.connect();
}
protected synchronized void buildGoogleApiClient() {
Log.d("BUILD", "In buildClient()");
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
@Override
public void onConnected(Bundle bundle) {
Log.d("ON_CONNECTED","In onConnected()");
Location MLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if (MLastLocation != null) {
latLng = new LatLng(MLastLocation.getLatitude(), MLastLocation.getLongitude());
} else {
Log.d("onConnected", "Value of LatLng is NULL");
latLng = new LatLng(0, 0);
}
}
public LatLng getLatLng(){
return this.latLng;
}
@Override
public void onConnectionSuspended(int i) {
//Notify
Log.d("ConnectionSuspended", "Connection Suspended. Status: " + i);
mgoogleMap.clear();
mGoogleApiClient.disconnect();
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
//Notify
Log.d("ConnectionFailed", "Connection Failed. Status: " + connectionResult.toString());
mgoogleMap.clear();
mGoogleApiClient.disconnect();
}
}
@Override
protected void onHandleIntent(Intent intent) {
//Instantiating the inner class
MapClassInner inner = new MapClassInner(map);
//Trying to access the inner LatLng variable
LatLng coords = inner.getLatLng();
//Gives me a NullPointerException
//Converting them to String values
String lat = String.valueOf(coords.latitude);
String lng = String.valueOf(coords.longitude);
//Sending broadcast Intent
Intent broadcastIntent = new Intent();
broadcastIntent.setAction(MyLocationReceiver.PROCESS_RESPONSE);
broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT);
broadcastIntent.putExtra(RESPONSE_LAT, lat);
broadcastIntent.putExtra(RESPONSE_LNG, lng);
sendBroadcast(broadcastIntent);
}
}
如何从内部类中获取LatLng
?我正在为此考虑EventBus。它会起作用吗?是的,请对我有点容易;我对Android& amp; Java的。
答案 0 :(得分:1)
我在所有代码中简化此操作所做的是创建一个静态的'AppData.java'类,并且可以从我的包中的任何类访问。然后我把这样的数据放在那里。
public class AppData
{
private static final AppData appData = new AppData(); // Make a static instance so it is not re-inited.
// My data
public Location lastKnownLocation;
/**
* Method to return the static instance of the AppData.
*
* @return An AppData object that is static so you can get/set global data across the application.
*/
public static AppData getInstance() {return appData;}
}
您可以添加getter和setter。我还给了我一个构造函数,它接受了一个Context,并且只从我的Main Activity调用了一次,它让我在类中实现了Preference Management,这对于我保留持久性的更复杂的数据很有帮助。
要在任何地方使用它,只需执行此操作:
AppData appData = AppData.getInstance();
appData.lastKnownLocation = <whatever your code does>
等等...