我是android新手。我想开发一个应用程序，我想只显示用户当前的纬度和经度，即使互联网没有连接。像这样的应用程序
https://play.google.com/store/apps/details?id=com.AndLocation.AndLocation&hl=en
我尝试过以下代码。如果连接互联网，纬度和长度会发生变化。但如果没有连接互联网，如果我改变我的位置，经度和经度保持不变。但另一个应用程序，即链接上面的应用程序运行良好..请帮助我。怎么做。
这是我的MainActivity
$ cygdb .
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License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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Traceback (most recent call last):
File "<string>", line 11, in <module>
ImportError: No module named 'Cython'
/tmp/tmpEkb_tX:19: Error in sourced command file:
Error while executing Python code.
(gdb) cy run abc.py
Undefined command: "cy". Try "help".
这是GPSTracker类
public class MainActivity extends AppCompatActivity {
private Toolbar toolbar;
GPSTracker gps;
TextView lat1, long1;
Button exit, refresh;
private PendingIntent pendingIntent;
private static MainActivity mInst;
double newLat, newLong;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.app_bar);
toolbar.setTitle("GPSFinder");
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
lat1 = (TextView) findViewById(R.id.latitude);
long1 = (TextView) findViewById(R.id.longitude);
exit = (Button) findViewById(R.id.button);
exit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
});
refresh = (Button) findViewById(R.id.buttonRefresh);
Intent alarmIntent = new Intent(MainActivity.this, AlarmReceiver.class);
pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, alarmIntent, 0);
startAlarm();
refresh.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
gps = new GPSTracker(MainActivity.this);
// check if GPS enable
if(gps.canGetLocation()){
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
lat1.setText(""+latitude);
long1.setText(""+longitude);
}else{
gps.showSettingsAlert();
}
}
});
gps = new GPSTracker(MainActivity.this);
// check if GPS enabled
if(gps.canGetLocation()){
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
lat1.setText(""+latitude);
long1.setText(""+longitude);
}else{
gps.showSettingsAlert();
}
}
public void startAlarm(){
AlarmManager manager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
/* Repeating on every 20 minutes interval */
manager.setRepeating(AlarmManager.RTC_WAKEUP, 0,
10 * 60 * 20, pendingIntent);
}
@Override
protected void onResume() {
super.onResume();
// Other onResume() code here
this.registerReceiver(mMessageReceiver, new IntentFilter("some_unique_name"));
}
@Override
protected void onPause() {
super.onPause();
this.unregisterReceiver(mMessageReceiver);
// Other onPause() code here
}
private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
// Extract data included in the Intent
String message = intent.getStringExtra("lat");
String msg2 = intent.getStringExtra("long");
// updateYourActivity(context);
lat1.setText(""+message);
long1.setText(""+msg2);
Log.e("dfsfdsf", "" + message);
Log.e("dsfdgdgdfgfd",""+msg2);
//update the TextView
// Toast.makeText(context, "Alarm Settttttttt", Toast.LENGTH_SHORT).show();
}
};
}
和AlarmReceiver类
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 0; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 5 minutes
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
} else {
this.canGetLocation = true;
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
* */
public void stopUsingGPS() {
if (locationManager != null) {
// if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// public void requestPermissions(@NonNull String[] permissions, int requestCode)
// 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 Activity#requestPermissions for more details.
return;
}
locationManager.removeUpdates(GPSTracker.this);
// }
}
/**
* Function to get latitude
* */
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
* @return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
}
我尝试使用闹钟管理器不断更新纬度和经度值。
我提供链接的应用程序在应用程序运行时显示设备状态栏上的位置图标，在我退出应用程序后它就消失了..
请帮我解决这个问题。
答案 0 :(得分：0)
在函数GetLocation中，您应该在代码的开头重置Location属性，否则它将不会进入从GPS获取if (location == null)代码块
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
在功能OnLocationChanged (Android.Locations.Location location)中，您应该收到新的GPS位置
@Override
public void onLocationChanged(Location location) {
double lon = location.Longitude;
double lat = location.Latitude;
}