Gluon position service is taking too long to display the coordinates - gps

Question

I tried the following code, it's working, but making the first click on the button after launching the app, the message with the coordinates show right when the button is clicked, but for the next clicks, the message takes long time unfortunately to display the message.
My code is as follows:
button.setOnAction(e->{
PositionService positionService = Services.get(PositionService.class).orElseThrow(() -> new RuntimeException("PositionService not available."));
positionService.positionProperty().addListener((obs, ov, nv) -> MobileApplication.getInstance().showMessage("Latest known GPS coordinates from device: " + nv.getLatitude() + ", " + nv.getLongitude()));
});
Thanks in advance.

Answer 1

Let's say you have a single view project created with the Gluon plugin for your IDE, and you have added the required location service and the permission to the Android manifest:
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
In the BasicView you can do for instance:
public BasicView(String name) {
super(name);
Label label = new Label("GPS is not active");
Button button = new Button("Active GPS");
button.setGraphic(new Icon(MaterialDesignIcon.LOCATION_ON));
button.setOnAction(e -> {
Services.get(PositionService.class).ifPresent(service -> {
// if there is GPS service, disable button to avoid adding more
// listeners
button.setDisable(true);
label.setText("Waiting for GPS signal");
service.positionProperty().addListener((obs, ov, nv) ->
label.setText("Latest known GPS coordinates:\n" + nv.getLatitude() + ", " + nv.getLongitude()));
});
});
VBox controls = new VBox(15.0, label, button);
controls.setAlignment(Pos.CENTER);
setCenter(controls);
}
Or you can initialize the service when you create the view, without the need to activate it:
public BasicView(String name) {
super(name);
Label label = new Label("GPS is not active");
Services.get(PositionService.class).ifPresent(service -> {
label.setText("Waiting for GPS signal");
service.positionProperty().addListener((obs, ov, nv) ->
label.setText("Latest known GPS coordinates:\n" + nv.getLatitude() + ", " + nv.getLongitude()));
});
}
Either way, you can deploy the app to your Android/iOS device and test.
EDIT
Optionally, if you want to include a button, so you can click on it as many time as you want.
public BasicView(String name) {
super(name);
Label label = new Label("GPS is not active");
Button button = new Button("Get GPS coordinates");
button.setGraphic(new Icon(MaterialDesignIcon.LOCATION_ON));
button.setDisable(true);
Services.get(PositionService.class).ifPresent(service -> {
label.setText("Waiting for GPS signal");
service.positionProperty().addListener((obs, ov, nv) -> {
label.setText("Latest known GPS coordinates:\n" + nv.getLatitude() + ", " + nv.getLongitude());
});
// enable button and add listener to retrieve coordinates
button.setDisable(false);
button.setOnAction(e -> {
Position position = service.getPosition();
MobileApplication.getInstance().showMessage("Latest known GPS coordinates from device:\n" +
position.getLatitude() + ", " + position.getLongitude());
});
});
VBox controls = new VBox(15.0, label, button);
controls.setAlignment(Pos.CENTER);
setCenter(controls);
}
Note that when clicking the button you should use service.getPosition().