Button for centering the map to our own geolocation

[cusspvz]

This issue is a proposal for introducing a button that handles the map centering to the user's geolocation.

[cusspvz]

@dagatsoin @EddyVerbruggen @anothar what's the difficulty we would have to implement this?

[Nauzer]

Hi @cusspvz.

Why not use your own button that you position on top of the map and use:

Mapbox.setCenter(
  {
    lat: 52.3602160, // mandatory
    lng: 4.8891680,  // mandatory
    animated: false  // default true
  }
);

[cusspvz]

Hey @Nauzer, thanks for your reply. Because we cannot place elements over the mapview yet.

[dagatsoin]

Right. I see those steps:

• create a custom View/Button
• add a click listener to it
• write a method to retrieve position
• add a RegisterUserPositionCallback to register a callback to send back the position to the JS part.
• optional: add an option to pass down a custom image for the button (inspired by https://github.com/Telerik-Verified-Plugins/Mapbox/pull/42)

[cusspvz]

@dagatsoin nice! Seems we got a path.

Although the button placement and position should be optional, don't you agree?

If I had to design an API I would do it like:

• having a boolean option on map creation that sets if the button will be actually visible/placed or not - geolocationButton
• having a callback, in case we want to pass to the JS side whenever that button was clicked - onGeolocationButtonClickCallback
• having an option to determine the button's position over the map - ENUM( 'top-left', 'top-right', 'bottom-left', 'bottom-right', 'middle-left', 'middle-right' ), as it should have a default I would choose 'top-left'.

Note: Doesn't the mapbox gl native provides some sort of controls mechanisms already?

[dagatsoin]

That seems good, but I would prefer the option to specify the layout params for the button instead of restrictive ENUM values so: (int width, int height, int left, int top, int right, int bottom)

[cusspvz]

Nice come up @dagatsoin ! I prefer it as well, but how would you handle the non-specified ones? Should they be int or either null, being null the default?

[dagatsoin]

What about passing an object {width, height, left, top, right, bottom}?

The native method should also have a default place/dimension. So the passing value will just override the default position.

About the implementation of the default position in the native method, I used to use LayoutParams object to set size and margin. I don't know a lot about android layout. Maybe @anothar could help us find a better way?