我在我的应用中实现了位置服务，最近我更新了它以获取后台位置更新。但是，我不确定这是否是“正确的方式”。我正在使用网络位置提供程序并调用onStart以尽快获取位置更新（0,0）。当用户最小化应用程序（应用程序进入后台并且调用onPause）时，我不太频繁地请求更新 - 每30分钟，每200米。我想知道我的逻辑是否正确，我的应用程序将在后台获得这些更新。我有两个类变量来存储经度和纬度值。
这是我的mainActvity代码：
public class MainActivity extends AppCompatActivity {
public double latitude = 0.0;
public double longitude = 0.0;
private MyLocationListener locationListner;
private LocationManager locationManager;
public boolean isFirstTimeLaunchingTheApp = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//-----------MY CODE STARTS HERE-----------------
mainActivityLayout = (LinearLayout)findViewById(R.id.main_activity_layout);
changeWindowTopColor();
this.mCurrent_forecast_fragment = new Current_forecast_fragment();
this.mHourly_forecast_fragment = new Hourly_forecast_fragment();
this.mDaily_forecast_fragment = new Daily_forecast_fragment();
locationListner = new MyLocationListener();
// Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
adapter = new ViewPagerAdapter(getSupportFragmentManager(), Titles, Numboftabs, mCurrent_forecast_fragment,
mHourly_forecast_fragment, mDaily_forecast_fragment);
// Assigning ViewPager View and setting the adapter
pager = (ViewPager) findViewById(R.id.pager);
pager.setOffscreenPageLimit(3);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setDistributeEvenly(true); // To make the Tabs Fixed set this true, This makes the tabs Space Evenly in Available width
// Setting Custom Color for the Scroll bar indicator of the Tab View
tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
@Override
public int getIndicatorColor(int position) {
return ContextCompat.getColor(MainActivity.this, R.color.tabsScrollColor);
}
});
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
}
@Override
protected void onResume() {
super.onResume();
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
if (locationManager == null) {
getLocation();
Log.d(TAG, "OnResume locationManager == null");
}
}
@Override
protected void onStart() {
super.onStart();
getLocation();
Log.d(TAG, "onStart getLocation");
}
@Override
protected void onPause() {
super.onPause();
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
locationManager.removeUpdates(locationListner);
//EVERY HALF AN HOUR
long minTime = 30 * 60 * 1000;
//EVERY 200 meters
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, minTime , 200 , locationListner);
Log.d(TAG, "requestLocationUpdates in the BACKGROUND...");
}
@Override
protected void onDestroy() {
if(locationManager != null) {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
locationManager.removeUpdates(locationListner);
Log.d(TAG,"removeUpdates - onDestroy");
}
super.onDestroy();
Log.d(TAG, "onDestroy called");
}
public void getLocation() {
if(!isFirstTimeLaunchingTheApp && isNetworkAvailable()){
final Snackbar snackbar = Snackbar
.make(mainActivityLayout, "Initial launch may take a bit more to load.", Snackbar.LENGTH_LONG)
.setAction("OK", new View.OnClickListener() {
@Override
public void onClick(View view) {
}
});
snackbar.show();
}
Log.d(TAG,"getLocation initiated...");
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
if (isNetworkAvailable()) {
// mCurrent_forecast_fragment.toggleRefresh();
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
//check if the if the location services are enabled
if( !isLocationServicesEnabled()) {
alertForNoLocationEnabled();
}else {
Log.d(TAG,"getLocation requestLocationUpdates...");
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER, 0, 0, locationListner);
}
} else {
alertForNoInternet();
Log.d(TAG, "Alert No Internet" + 366);
}
}
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location loc) {
Log.d(TAG,"On Location changed...");
latitude = loc.getLatitude();
longitude = loc.getLongitude();
//check if this is the first time that the app starts
//if it is not, get the forecast only with the swiperefresh layout
if(!isFirstTimeLaunchingTheApp) {
getForecast(latitude, longitude);
isFirstTimeLaunchingTheApp = true;
}
}
答案 0 :(得分：0)
requestlocationUpdate()都会调用侦听器的onLocationChanged()方法，并且它也会在后台执行。
您可以使用AsyncTask或Service解决此问题。
使用Service：
public class loc extends Service
{
LocationManager loc_manager;
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// TODO Auto-generated method stub
loc_manager=(LocationManager)getSystemService(Context.LOCATION_SERVICE);
loc_manager.requestLocationUpdates("gps",0,0,listener);
return super.onStartCommand(intent, flags, startId);
}
LocationListener listener=new LocationListener() {
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
}
};
}
别忘了在Manifest文件中注册您的服务和位置权限。