【发布时间】：2017-05-20 22:11:49
【问题描述】：
我正在构建一个朋友跟踪 Android 应用。当我的朋友激活该应用程序并带着他的 GPS 和蜂窝数据离开时，我需要在我的设备上跟踪他。就是这个概念。
我已经实现了 LocationListener 类，现在我可以从 Gps 或网络获取最后更新的位置，但除非我启动 Google 地图并返回到我的应用程序，否则不会更新。谷歌搜索后，我了解到位置缓存仅由 GMaps 更新。！
- 是否有其他方法可以持续更新位置？
- 如果我需要在设备锁定后不使用 Wakelock 继续获取位置怎么办？
这是我的位置监听类：
package com.amazinginside;
/** AMAZING LOCATION SUPPORT CLASS, Devoloped By SANGEETH NANDAKUMAR */
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
public class AmazingLocation extends Service implements LocationListener
{
private final Context mContext;
boolean isGPSEnabled = false;
boolean isNetworkEnabled = false;
boolean canGetLocation = false;
Location location;
double latitude=0.0;
double longitude=0.0;
//MINIMUM DISTANCE FOR UPDATE (meters)
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 0; // 0 Meters
//MINIMUM TIME BETWEEN UPDATES
private static final long MIN_TIME_BW_UPDATES = 1000 * 0; // 0 Seconds
//LOCATION MANAGER
protected LocationManager locationManager;
//CONSTRUCTOR
public AmazingLocation(Context context)
{
this.mContext = context;
getLocation();
}
//LOCATION PROVISION
public Location getLocation()
{
try
{
//GET LOCATION MANAGER
locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE);
//CHECK GPS STATE
isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
//CHECK NETWORK STATE
isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled)
{
//NO LOCATION PROVIDERS
}
else
{
this.canGetLocation = true;
/** GET LOCATION FROM NETWORK */
//FIRST GET LOCATION FROM NETWORK
if (isNetworkEnabled)
{
//REQUEST LOCATION
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if (locationManager != null)
{
//START WITH LAST KNOWN LOCATION
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
//EXTRACT LOCATION
if (location != null)
{
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
/** GET LOCATION FROM GPS SENSOR */
//THEN GET LOCATION FROM GPS
if (isGPSEnabled)
{
if (location == null)
{
//REQUEST GPS LOCATION
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if (locationManager != null)
{
//EXTRACT LAST KNOWN LOCATION
location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
//RETURN LOCATION
if (location != null)
{
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
}
catch (Exception e)
{
e.printStackTrace();
}
return location;
}
//STOP GPS SENSOR
public void stopUsingGPS()
{
if(locationManager != null)
{
locationManager.removeUpdates(AmazingLocation.this);
}
}
//EXTRACT LATTITUDE
public double getLatitude()
{
if(location != null)
{
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
//EXTACT LONGITUDE
public double getLongitude()
{
if(location != null)
{
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
//CAN I GET THE LOCATION.?
public AmazingStatus canGetLocation()
{
AmazingStatus status=new AmazingStatus();
if(this.canGetLocation)
{
status.setStatus(true);
status.setErrorcode(0);
status.setErrormsg("Task completed");
}
else
{
status.setStatus(false);
status.setErrorcode(145);
status.setErrormsg("Please turn on GPS access manually");
}
return status;
}
//SHOW LOCATION SETTINGS
public AmazingStatus showSettingsAlert()
{
final AmazingStatus status=new AmazingStatus();
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
alertDialog.setTitle("REQUIRES LOCATION ACCESS");
alertDialog.setMessage("Please allow GPS access to this app");
//POSSITIVE REPLY
alertDialog.setPositiveButton("Allow", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog,int which)
{
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
status.setStatus(true);
status.setErrorcode(0);
status.setErrormsg("Task completed");
}
});
//NEGATIVE REPLY
alertDialog.setNegativeButton("Deny", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
status.setStatus(false);
status.setErrorcode(408);
status.setErrormsg("User denied permission");
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
return status;
}
//UNUSED OVERRIDE METHORDS...
@Override
public void onLocationChanged(Location location)
{
getLocation();
}
@Override
public void onProviderDisabled(String provider)
{
}
@Override
public void onProviderEnabled(String provider)
{
getLocation();
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras)
{
getLocation();
}
@Override
public IBinder onBind(Intent arg0)
{
return null;
}
}
这是我的onCreate() 方法：
@Override protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//CREATE A BUTTON HANDLER
Button start_btn=(Button)findViewById(R.id.start_location_streaming);
//ON BUTTON CLICK EVENT
start_btn.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
//REPEAT A METHORD AT SPECIFIC INTERVALS
Timer myTimer = new Timer();
myTimer.schedule(new TimerTask()
{
@Override
public void run()
{
TimerMethod();
}
}, 0, 8000);
}
}); }
这些是其他方法：
private void TimerMethod()
{
//START METHORD
this.runOnUiThread(Timer_Tick);
}
//LOCATION REPORTING METHORD
private Runnable Timer_Tick = new Runnable()
{
public void run()
{
Toast.makeText(MainActivity.this, "Current latitude : "+Double.toString(getLocation().latitude), Toast.LENGTH_SHORT).show();
Toast.makeText(MainActivity.this, "Current longitude : "+Double.toString(getLocation().longitude), Toast.LENGTH_SHORT).show();
}
};
private LatLng getLocation()
{
//CREATE A LOCATION CLASS INSTANCE
AmazingLocation gps = new AmazingLocation(this);
//RETRIVE LOCATION
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
//RETURN LOCATION
LatLng loc=new LatLng(latitude,longitude);
return loc;
}
现在的问题是，toast 只显示先前已知的位置，并且不会更新，除非我打开 Google 地图并返回。
任何帮助都会对我有很大帮助。
【问题讨论】：
-
您的代码已损坏。您正在使用名为 GPSTracker 的旧代码的变体。这段代码设计得很糟糕，充满了错误——尤其是它不知道提供程序启用和实际启用之间的区别。
-
谢谢加布先生。实际上我很惊讶，因为这段代码被预先破坏了。让我看看你提供的链接。
-
嗨 Kannan.. 你能解决这个问题吗？
-
我的 Google Play 服务有问题。融合位置提供程序的工作原理
-
它是喀拉拉邦的 chitappan 追踪器..