Revisit headless device selection #34
Description
Since implementing the Web Bluetooth extensions for bleat here, I've ben thinking about possibly implementing the headless device selection UI in a different way. I think maybe having a way of registering a developer-created UI which doesn't dirty the main specification could be a different way to go. This could be implemented in one of two ways.
- With an event handler
// New, separate root function to register a requestDevice() scan handler
bluetooth.addScanHandler(function(scanner) {
// This function is called whenever 'requestDevice()' is executed.
// The scanner object looks like:
// {
// scan: function to start a scan
// devices: [] of found devices
// resolve: requestDevice.Promise.resolve
// reject: requestDevice.Promise.reject
// }
// This event fires when scanner.devices are changed
scanner.addEventListener("deviceschanged", updateUI);
// When scanner.devices have changed
function updateUI(device) {
// Show UI
scanner.devices.forEach(function(device) {
...
});
}
// When a user chooses
function chooseDevice(index) {
var device = scanner.devices[index];
scanner.resolve(device);
}
// Begin scan
scanner.scan();
});- With a callback function
// New, separate root function to register a requestDevice() scan handler
bluetooth.addScanHandler(function(scanner) {
// This function is called whenever 'requestDevice()' is executed.
// The scanner object looks like:
// {
// scan: function to start a scan
// onDeviceFound: function to register a device found callback
// resolve: requestDevice.Promise.resolve
// reject: requestDevice.Promise.reject
// }
// This function is called when a device is found
scanner.onDeviceFound(updateUI);
// Store devices
var devices = [];
function updateUI(device) {
devices.push(device);
// Show UI
}
// When a user chooses
function chooseDevice(index) {
var device = devices[index];
scanner.resolve(device);
}
// Begin scan
scanner.scan();
});You can then use requestDevice() just as before:
bluetooth.requestDevice({
...
})
.then(device => ...Either of these methods could be used to undertake eddystone scanning, too.
@mikaelkindborg, @jyasskin is this a preferable approach, or do you have any further thoughts?