我正在创建一个Android应用程序，用于从Google商家信息中获取数据并在列表视图中显示数据。问题是asynctask不断刷新并发出http请求，最终导致我的适配器上出现outOfBounds。我正在使用服务来获取设备的位置并将其发送到通过广播接收器获取位置的活动。
onResume一直被调用的问题是什么？
广播接收机的onRecieve方法是否经常被调用？
服务上的locationListener是否重复？
提前致谢！
使用listView，broadcastReceiver和AsyncTask的活动：
public class NearbyLocationsActivity extends BaseActivity implements AsyncDelegate {
private Location mLastLocation;
private GetLocations nearbyLocations;
private PlaceAdapter adapter;
private ArrayList<Place> nearbyPlaces;
private double mLat;
private double mLong;
private ListView locationsList;
public Spinner typesSpinner;
private BroadcastReceiver broadcastReceiver;
private String radius = "10000";
private int selectedSpinnerIndex;
private String [] types = {"everything", "restaurant", "bar", "museum", "night_club", "cafe", "movie_theater"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_nearby_locations);
locationsList = (ListView) findViewById(R.id.locations_list);
typesSpinner = (Spinner) findViewById(R.id.type_spinner);
nearbyPlaces = new ArrayList();
adapter = new PlaceAdapter(getApplicationContext(), nearbyPlaces);
locationsList.setAdapter(adapter);
if(!runtimePermissions()) {
enableService();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
return true;
}
public void enableService() {
Intent i = new Intent(getApplicationContext(), LocationService.class);
startService(i);
}
private boolean runtimePermissions() {
if (Build.VERSION.SDK_INT >= 23 && ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED
&& ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION,
Manifest.permission.ACCESS_COARSE_LOCATION}, 100);
return true;
}
return false;
}
@Override
public void onResume() {
super.onResume();
if (broadcastReceiver == null) {
broadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
mLastLocation = (Location) intent.getExtras().get("coordinates");
mLat = mLastLocation.getLatitude();
mLong = mLastLocation.getLongitude();
nearbyLocations = new GetLocations(NearbyLocationsActivity.this);
nearbyLocations.execute();
}
};
}
registerReceiver(broadcastReceiver, new IntentFilter("location_updates"));
}
@Override
public void onDestroy() {
super.onDestroy();
if (broadcastReceiver != null) {
unregisterReceiver(broadcastReceiver);
}
}
@Override
public void onStop() {
Intent i = new Intent(getApplicationContext(), LocationService.class);
stopService(i);
super.onStop();
}
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == 100) {
if (grantResults[0] == PackageManager.PERMISSION_GRANTED && grantResults[1] == PackageManager.PERMISSION_GRANTED) {
enableService();
} else {
runtimePermissions();
}
}
}
@Override
public void asyncComplete(boolean success) {
typesSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
selectedSpinnerIndex = typesSpinner.getSelectedItemPosition();
new GetLocations(NearbyLocationsActivity.this).execute();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
selectedSpinnerIndex = 0;
}
});
locationsList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Place p = adapter.getItem(position);
Intent intent = new Intent(getApplicationContext(), CreateEventActivity.class);
intent.putExtra("selectedPlace", p);
startActivity(intent);
}
});
}
public class GetLocations extends AsyncTask<Void, Void, Void> {
private AsyncDelegate delegate;
public GetLocations (AsyncDelegate delegate){
this.delegate = delegate;
}
@Override
protected Void doInBackground(Void... params) {
nearbyPlaces.clear();
StringBuilder sb = new StringBuilder();
String http = "https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=" + mLat + "," + mLong +
"&radius=10000";
if (selectedSpinnerIndex != 0) {
http += "&types=" + types[selectedSpinnerIndex];
}
http += "&key=AIzaSyDFb37i6VGPj2EG6L7dLO5H7tDhLCqCW2k";
HttpURLConnection urlConnection;
try {
URL url = new URL(http);
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
if (urlConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
String line;
while ((line = reader.readLine()) != null) {
sb.append(line);
}
}
JSONObject jsonObject = new JSONObject(sb.toString());
JSONArray array = jsonObject.getJSONArray("results");
for (int i = 0; i < array.length(); i++) {
JSONObject placeLine = (JSONObject) array.get(i);
Place place = new Place();
JSONObject geometryLine = placeLine.getJSONObject("geometry");
JSONObject locationLine = geometryLine.getJSONObject("location");
Place.Location location = new Place.Location();
location.setLat(locationLine.getDouble("lat"));
location.setLon(locationLine.getDouble("lng"));
place.setLocation(location);
place.setIcon(placeLine.getString("icon"));
place.setPlaceId(placeLine.getString("place_id"));
String detailsHttp = "https://maps.googleapis.com/maps/api/place/details/json?key=AIzaSyDFb37i6VGPj2EG6L7dLO5H7tDhLCqCW2k&placeid=" + place.getPlaceId();
getPlaceDetails(detailsHttp, place);
place.setName(placeLine.getString("name"));
/*JSONArray typesJson = new JSONArray("types");
String [] types = new String[typesJson.length()];
for (int a = 0; i < typesJson.length(); i++) {
types[a] = typesJson.getString(a);
}
place.setTypes(types);*/
place.setVicinity(placeLine.getString("vicinity"));
try {
place.setRating(placeLine.getInt("rating"));
} catch (JSONException je) {
place.setRating(-1);
}
try {
JSONArray photosJson = placeLine.getJSONArray("photos");
//for (int k = 0; i < photosJson.length(); i++) {
JSONObject photoLine = (JSONObject) photosJson.get(0);
String photoHttp = "https://maps.googleapis.com/maps/api/place/photo?maxwidth=400&" +
"photoreference=" + photoLine.getString("photo_reference") + "&key=AIzaSyDFb37i6VGPj2EG6L7dLO5H7tDhLCqCW2k";
place.setPhotoHttp(photoHttp);
//place.addPhotoHttp(photoHttp);
//}
} catch (JSONException je) {
place.setPhotoHttp(null);
}
nearbyPlaces.add(place);
}
} catch(MalformedURLException mue){
System.out.println("A malformed URL exception occurred. " + mue.getMessage());
} catch(IOException ioe){
System.out.println("A input/output exception occurred. " + ioe.getMessage());
} catch(JSONException je){
System.out.println("A JSON error occurred. " + je.getMessage());
}
return null;
}
public void getPlaceDetails(String http, Place p) {
StringBuilder sb = new StringBuilder();
HttpURLConnection urlConnection;
try {
URL url = new URL(http);
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
if (urlConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
String line;
while ((line = reader.readLine()) != null) {
sb.append(line);
}
}
JSONObject jsonObject = new JSONObject(sb.toString());
JSONObject resultsJson = jsonObject.getJSONObject("result");
String address = resultsJson.getString("formatted_address");
p.setAddress(address);
} catch(MalformedURLException mue){
System.out.println("A malformed URL exception occurred. " + mue.getMessage());
} catch(IOException ioe){
System.out.println("A input/output exception occurred. " + ioe.getMessage());
} catch(JSONException je){
System.out.println("A JSON error occurred. " + je.getMessage());
}
}
@Override
protected void onPostExecute(Void aVoid) {
// Thread is finished downloading and parsing JSON, asyncComplete is
adapter.notifyDataSetChanged();
delegate.asyncComplete(true);
}
}}
检索设备位置的服务：
public class LocationService extends Service {
private LocationListener listener;
private LocationManager locationManager;
@Override
public void onCreate() {
super.onCreate();
listener = new LocationListener() {
@Override
public void onLocationChanged(Location location) {
Intent i = new Intent("location_updates");
i.putExtra("coordinates", location);
sendBroadcast(i);
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
Intent i = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(i);
}
};
locationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
//noinspection MissingPermission
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 3000, 0, listener);
}
@Override
public void onDestroy() {
super.onDestroy();
if (locationManager != null) {
locationManager.removeUpdates(listener);
}
}
public IBinder onBind(Intent intent) {
return null;
}}
listview的适配器：
public class PlaceAdapter extends ArrayAdapter<Place> {
private Context mContext;
private ArrayList<Place> places;
public PlaceAdapter(Context context, ArrayList<Place> nearbyPlaces) {
super(context, R.layout.place_list_item, nearbyPlaces);
mContext = context;
this.places = nearbyPlaces;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(mContext);
View view = inflater.inflate(R.layout.place_list_item, null);
final Place p = places.get(position);
TextView placeName = (TextView) view.findViewById(R.id.place_name);
placeName.setText(p.getName());
TextView placeAddress = (TextView) view.findViewById(R.id.place_address);
placeAddress.setText(p.getAddress());
ImageView placeImage = (ImageView) view.findViewById(R.id.place_picture);
if (p.getPhotoHttp() != null) {
Picasso.with(mContext).load(p.getPhotoHttp()).into(placeImage);
} else {
Picasso.with(mContext).load(p.getIcon()).into(placeImage);
}
return view;
}}
答案 0 :(得分：0)
@Override
public void onResume() {
super.onResume();
if (broadcastReceiver == null) {
broadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
mLastLocation = (Location) intent.getExtras().get("coordinates");
mLat = mLastLocation.getLatitude();
mLong = mLastLocation.getLongitude();
nearbyLocations = new GetLocations(NearbyLocationsActivity.this);
nearbyLocations.execute();
}
};
registerReceiver(broadcastReceiver, new IntentFilter("location_updates"));
}
}
如果阻止
，则将registerReceiver移入内部