Layer loading spinner proof-of-concept

[giswqs]

This is a proof-of-concept of the layer loading spinner. It works in JupyterLab, but does not work VS Code. Bug reported on the ipywdiget repo. jupyter-widgets/ipywidgets#3909

import ee
import geemap
import ipywidgets as widgets

m = geemap.Map()
image = ee.Image('USGS/SRTMGL1_003')
vis = {'min': 0, 'max': 4000, 'palette': 'terrain'}
layer = geemap.ee_tile_layer(image, vis, 'SRTM DEM')
m.add_layer(layer)

spinner = widgets.Button(description='Loading ...', icon='spinner spin lg')
m.add_widget(spinner, position='topright')

def loading_change(change):
    if change['new']:
        spinner.description = "Loading ..."
        spinner.icon = "spinner spin lg"
    else:
        spinner.description = "Loaded"
        spinner.icon = "check"        
layer.observe(loading_change, 'loading')
m