AsyncTask的doInBackground块locationManager
AsyncTask的doInBackground块locationManager
提问于 2016-03-16 12:34:08
我只想找到用户的位置一次，并显示一个ProgressDialog (PD)，直到这个位置是未知的。
我使用的是AsyncTask，在onPreExecute()中显示PD，调用locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, listener);。因为使用GPS查找位置可能需要很长时间，所以在doInBackground()中，我通过调用listener.isLocationAvailable()来检查位置是否可用。
在用for(int i = 0; i < 100; i++) {...}循环替换while循环之后，输出将是下一个：
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling
I/System.out: cycling100次..。
I/System.out: 65.9667, -18.5333
I/System.out: 65.9667, -18.5333
I/System.out: 65.9667, -18.5333
I/System.out: 65.9667, -18.5333
I/System.out: 65.9667, -18.5333
I/System.out: 65.9667, -18.5333
I/System.out: 65.9667, -18.5333(在调用onLocationChanged(位置位置)时，在100次循环后显示100倍)
下面是AsyncTask：
private class PositioningTask extends AsyncTask<Void, Void, String> {
Context context = TransportActivity.this;
ProgressDialog progressDialog;
TransportLocationListener listener;
LocationManager locationManager;
private boolean gpsEnabled;
private boolean networkEnabled;
@Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog = new ProgressDialog(TransportActivity.this);
progressDialog.setTitle("Loading position, please wait");
progressDialog.setMessage(getString(R.string.please_wait));
progressDialog.setCancelable(false);
progressDialog.show();
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
listener = new TransportLocationListener();
if (ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED
|| ContextCompat.checkSelfPermission(context, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, listener);
}
}
@Override
protected String doInBackground(Void... params) {
String position = "";
try{
while (true){
if (listener.isLocationAvailable()) {
Location location = listener.getLocation();
position = location.getLatitude() + "," + location.getLongitude();
if (ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED
|| ContextCompat.checkSelfPermission(context, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
locationManager.removeUpdates(listener);
}
System.out.println("POSITION: " + position);
break;
}
System.out.println("cycling");
Thread.sleep(1000);
}
}
catch (InterruptedException e) {
e.printStackTrace();
}
return position;
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
progressDialog.dismiss();
}
}TransportLocationListener：
public class TransportLocationListener implements LocationListener {
private Location location = null;
private Boolean available = false;
public boolean isLocationAvailable() {
return available;
}
public Location getLocation() {
return location;
}
@Override
public void onLocationChanged(Location location) {
this.location = location;
available = true;
System.out.println(location.getLatitude() + ", " + location.getLongitude());
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}}
回答 1
Stack Overflow用户
发布于 2016-03-16 13:20:11
AsyncTask的doInBackground块locationManager
我想您的问题是，您得到的位置更新源源不断？
以下是您的请求：
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, listener);是以minTime = 0和minDistance = 0接收位置更新。这意味着，即使位置没有改变，'onLocationChanged‘也会被调用。将此值更改为1000和0.1f，以减少使用实际新值调用onLocationChanged的频率。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/36035833
复制相关文章
相似问题
腾讯云开发者
