# wx.onBLECharacteristicValueChange(function callback)
Start from base library version 1.1.0. Please remaining backward compatible.
with Promise style call: Not supported
Mini Program plugin: Support, need to Mini Program base library version no less than 2.9.1
Monitor eigenvalue change events for Bluetooth low-power devices. Must be invoked first wx.notifyBLECharacteristicValueChange Interface to receive the device push notification。
# parameter
# function callback
Callback Functions for Eigenvalue Change Events of Bluetooth Low Power Devices
# parameter
# Object res
attribute | type | Introductions |
---|---|---|
deviceId | string | Bluetooth Device id |
serviceId | string | Bluetooth Feature Corresponding Service UUID |
characteristicId | string | Bluetooth characteristic UUID |
value | ArrayBuffer | Characteristic latest value |
# sample code
// ArrayBuffer to hexadecimal string example
function ab2hex(buffer) {
let hexArr = Array.prototype.map.call(
new Uint8Array(buffer),
function(bit) {
return ('00' + bit.toString(16)).slice(-2)
}
)
return hexArr.join('')
}
wx.onBLECharacteristicValueChange(function(res) {
console.log(`characteristic ${res.characteristicId} has changed, now is ${res.value}`)
console.log(ab2hex(res.value))
})