public class LocationTest extends Activity {
private static final String[] S = { "out of service", "temporarily unavailable", "available" };
ArrayList<Location> list = new ArrayList<Location>();
private TextView output;
private String best;
LocationListener locationListener;
LocationManager mgr;
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
output = (TextView) findViewById(R.id.output);
mgr = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
best = mgr.getBestProvider(criteria, true);
log("\nBest provider is: " + best);
locationListener = new LocationListener(){
public void onLocationChanged(Location location){
dumpLocation(location);
list.add(location);
}
public void onStatusChanged(String provider, int status, Bundle extras){
log("\nProvider status changed: " + provider + ", status=" + S[status]);
}
public void onProviderEnabled(String provider){
log("\nProvider enabled: " + provider);
}
public void onProviderDisabled(String provider){
log("\nProvider disabled: " + provider);
}
};
}
@Override
protected void onResume(){
super.onResume();
mgr.requestLocationUpdates(best, 120000, 50, locationListener);
}
@Override
protected void onPause(){
super.onPause();
mgr.removeUpdates(locationListener);
log_gen(list);
}
每当获得新修补程序时，应用程序当前都会显示经度和纬度。但是，跟踪仅在屏幕上显示“活动”时才会生效，并且只要用户退出应用程序，跟踪就会停止。我希望我的应用程序做的是即使退出应用程序也会在后台跟踪用户。例如，每当他在几分钟后重新打开应用程序时，背景中捕获的所有坐标都应显示在屏幕上。
根据我目前的研究，有两种方法可以解决这个问题：使用后台服务进行跟踪或使用
requestLocationUpdates (String provider, long minTime, float minDistance, PendingIntent intent)
与BroadcastReceiver结合使用即使用户退出应用也会继续获取位置更新。如果我理解正确，第二种方法将继续在后台运行。有人可以在代码中向我展示如何使用BroadcastReceiver
requestLocationUpdates
非常感谢提前。
答案 0 :(得分：0)
使用以下代码，您可以很好地获得定期位置更新，如果您担心持续运行的服务，您可以自定义获取位置更新的时间间隔，您还需要在您的应用中集成Google Play服务，以便以下顺序代码工作
public class BackgroundLocationService extends Service implements
GooglePlayServicesClient.ConnectionCallbacks,
GooglePlayServicesClient.OnConnectionFailedListener, LocationListener {
IBinder mBinder = new LocalBinder();
private LocationClient mLocationClient;
private LocationRequest mLocationRequest;
// Flag that indicates if a request is underway.
private boolean mInProgress;
private static final String TAG = BackgroundLocationService.class
.getSimpleName();
private Boolean servicesAvailable = false;
public class LocalBinder extends Binder {
public BackgroundLocationService getServerInstance() {
return BackgroundLocationService.this;
}
}
@Override
public void onCreate() {
super.onCreate();
mInProgress = false;
// Create the LocationRequest object
mLocationRequest = LocationRequest.create();
// Use high accuracy
mLocationRequest
.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
// Set the update interval to 5 seconds
mLocationRequest.setInterval(Constants.UPDATE_INTERVAL);
// Set the fastest update interval to 1 second
mLocationRequest.setFastestInterval(Constants.FASTEST_INTERVAL);
servicesAvailable = servicesConnected();
/*
* Create a new location client, using the enclosing class to handle
* callbacks.
*/
mLocationClient = new LocationClient(this, this, this);
}
private boolean servicesConnected() {
// Check that Google Play services is available
int resultCode = GooglePlayServicesUtil
.isGooglePlayServicesAvailable(this);
// If Google Play services is available
if (ConnectionResult.SUCCESS == resultCode) {
return true;
} else {
return false;
}
}
public int onStartCommand(Intent intent, int flags, int startId) {
super.onStartCommand(intent, flags, startId);
if (!servicesAvailable || mLocationClient.isConnected() || mInProgress)
return START_STICKY;
setUpLocationClientIfNeeded();
if (!mLocationClient.isConnected() || !mLocationClient.isConnecting()
&& !mInProgress) {
mInProgress = true;
mLocationClient.connect();
}
return START_STICKY;
}
/*
* Create a new location client, using the enclosing class to handle
* callbacks.
*/
private void setUpLocationClientIfNeeded() {
if (mLocationClient == null)
mLocationClient = new LocationClient(this, this, this);
}
// Define the callback method that receives location updates
@Override
public void onLocationChanged(final Location location) {
// Report to the UI that the location was updated
String msg = Double.toString(location.getLatitude()) + ","
+ Double.toString(location.getLongitude());
Log.d("debug", msg);
if (location != null) {
// location has the latitude and longitude
}
// Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
}
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
public String getTime() {
SimpleDateFormat mDateFormat = new SimpleDateFormat(
"yyyy-MM-dd HH:mm:ss", Locale.US);
return mDateFormat.format(new Date());
}
@Override
public void onDestroy() {
// Turn off the request flag
mInProgress = false;
if (servicesAvailable && mLocationClient != null) {
mLocationClient.removeLocationUpdates(this);
// Destroy the current location client
mLocationClient = null;
}
// Display the connection status
// Toast.makeText(this, DateFormat.getDateTimeInstance().format(new
// Date()) + ": Disconnected. Please re-connect.",
// Toast.LENGTH_SHORT).show();
super.onDestroy();
}
/*
* Called by Location Services when the request to connect the client
* finishes successfully. At this point, you can request the current
* location or start periodic updates
*/
@Override
public void onConnected(Bundle bundle) {
// Request location updates using static settings
mLocationClient.requestLocationUpdates(mLocationRequest, this);
}
/*
* Called by Location Services if the connection to the location client
* drops because of an error.
*/
@Override
public void onDisconnected() {
// Turn off the request flag
mInProgress = false;
// Destroy the current location client
mLocationClient = null;
// Display the connection status
// Toast.makeText(this, DateFormat.getDateTimeInstance().format(new
// Date()) + ": Disconnected. Please re-connect.",
// Toast.LENGTH_SHORT).show();
}
/*
* Called by Location Services if the attempt to Location Services fails.
*/
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
mInProgress = false;
/*
* Google Play services can resolve some errors it detects. If the error
* has a resolution, try sending an Intent to start a Google Play
* services activity that can resolve error.
*/
if (connectionResult.hasResolution()) {
// If no resolution is available, display an error dialog
} else {
}
}