【发布时间】：2013-03-01 19:45:17
【问题描述】：
如果我的问题重复或简单，请向我道歉。在这个问题上纠结了很久。
即使我的应用切换到后台，我也需要跟踪用户的位置。在网上冲浪时，我发现可以将位置处理器代码编写为服务，这样服务就不会被杀死，我们可以获取用户的位置（在两种状态 - 应用程序在前台和应用程序在后台运行时）。
当我的应用程序处于前台时，我能够持续跟踪用户的位置。但是，当我将应用程序切换到后台时，我觉得我的位置服务停止了，并且我无法跟踪用户的位置。请在下面找到我的代码：
AndroidManifest.xml：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.testmylocation"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".MyService"/>
</application>
</manifest>
MainActivity.java：
package com.example.testmylocation;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.Window;
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
startService(new Intent(this, MyService.class));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
MyService.java：
package com.example.testmylocation;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.URL;
import java.net.URLConnection;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.json.JSONArray;
import org.json.JSONObject;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.util.Log;
public class MyService extends Service
{
private static final String TAG = "TestMyLocation";
private LocationManager mLocationManager = null;
private static final int LOCATION_INTERVAL = 0;
private static final float LOCATION_DISTANCE = 0;
long itsBatchId = 0;
private class LocationListener implements android.location.LocationListener
{
Location mLastLocation;
public LocationListener(String provider)
{
mLastLocation = new Location(provider);
}
@Override
public void onLocationChanged(Location location)
{
Thread aThread = new Thread(new Runnable() {
@Override
public void run() {
sendLocationValues(location);
}
});
aThread.start();
}
@Override
public void onProviderDisabled(String provider)
{
Log.e(TAG, "onProviderDisabled: " + provider);
}
@Override
public void onProviderEnabled(String provider)
{
Log.e(TAG, "onProviderEnabled: " + provider);
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras)
{
Log.e(TAG, "onStatusChanged: " + provider);
}
}
private void sendLocationValues(Location theLocation)
{
//A web service will be called and the user's current location will be stored in server
}
LocationListener[] mLocationListeners = new LocationListener[]
{
new LocationListener(LocationManager.GPS_PROVIDER),
new LocationListener(LocationManager.NETWORK_PROVIDER)
};
@Override
public IBinder onBind(Intent arg0)
{
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId)
{
super.onStartCommand(intent, flags, startId);
return START_STICKY;
}
@Override
public void onCreate()
{
initializeLocationManager();
itsLocationHandler.sendEmptyMessage(1);
}
private Handler itsLocationHandler = new Handler()
{
@Override
public void handleMessage(Message theMessage)
{
if(theMessage.what == 1)
{
try
{
mLocationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, LOCATION_INTERVAL, LOCATION_DISTANCE, mLocationListeners[1]);
}
catch (java.lang.SecurityException ex)
{
Log.i(TAG, "fail to request location update, ignore", ex);
}
catch (IllegalArgumentException ex)
{
Log.d(TAG, "network provider does not exist, " + ex.getMessage());
}
}
}
};
@Override
public void onDestroy()
{
super.onDestroy();
}
private void initializeLocationManager()
{
if (mLocationManager == null)
{
mLocationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
}
}
}
谁能纠正我做错了什么。
谢谢。
【问题讨论】：
-
您需要对用户进行持续跟踪还是可以间隔进行？
-
我也可以每隔一段时间跟踪它的位置。仅出于测试目的，我使用了 LocationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, mLocationListeners[1]);