Initializing Bluetooth
Before using Bluetooth, you need to initialize The Bluetooth (openBluetoothAdapter) first, then you can call various bluetooth apis. Initial state is divided into two kinds: initial success: when can go to search the bluetooth devices (startBluetoothDevicesDiscovery). Initialization failed: this time need to prompt the user to open the bluetooth, monitor the state of the bluetooth (onBluetoothAdapterStateChange) at the same time, while bluetooth enabled, to search for equipment.
openBluetoothAdapter() {
const that = this
wx.openBluetoothAdapter({
success: (res) = > {
console.log('openBluetoothAdapter success', res)
// Initialization is successful, go to search the device
this.startBluetoothDevicesDiscovery()
},
fail: (res) = > {
if (res.errCode === 10001) {
// Bluetooth is not enabled
wx.onBluetoothAdapterStateChange(function (res) {
console.log('onBluetoothAdapterStateChange', res)
if (res.available) {
that.startBluetoothDevicesDiscovery()
}
})
}
}
})
}
Copy the codeSearch for Bluetooth devices
Began to search nearby bluetooth devices (startBluetoothDevicesDiscovery), the operation is consuming resources, advice after the connection to the bluetooth device, manually stop the search.
startBluetoothDevicesDiscovery() {
if (this._discoveryStarted) {
return
}
this._discoveryStarted = true
// Start searching for Bluetooth devices. AllowDuplicatesKey will search for the same device repeatedly
wx.startBluetoothDevicesDiscovery({
allowDuplicatesKey: true.success: (res) = > {
console.log('startBluetoothDevicesDiscovery success', res)
this.onBluetoothDeviceFound()
},
})
}
Copy the codeObtaining bluetooth Devices
There are two apis for obtaining bluetooth devices.
onBluetoothDeviceFound: Get the newly discovered device, willstartBluetoothDevicesDiscoveryIn theallowDuplicatesKeySet totrue, the method repeatedly reports the same Bluetooth device.getBluetoothDevices: Obtains the list of discovered Bluetooth devices. The number of Bluetooth devices obtained by this method is related to the search time. After the search for Bluetooth devices starts, this method is invoked after a period of time.
onBluetoothDeviceFound() {
// Get the newly discovered Bluetooth device
wx.onBluetoothDeviceFound((res) = > {
res.devices.forEach(device= > {
if(! device.name && ! device.localName) {return
}
const foundDevices = this.data.devices
const idx = inArray(foundDevices, 'deviceId', device.deviceId)
const data = {}
if (idx === - 1) {
data[`devices[${foundDevices.length}] `] = device
} else {
data[`devices[${idx}] `] = device
}
this.setData(data)
})
})
}
Copy the codeConnect bluetooth device
CreateBLEConnection: Connect the Bluetooth device, basically at this point, the Bluetooth device is connected. To avoid multiple connection instances for a device, closeBLEConnection is usually called in pairs. After the connection is successful, you need to call stopBluetoothDevicesDiscovery, stop search the bluetooth.
createBLEConnection(e) {
const ds = e.currentTarget.dataset
const deviceId = ds.deviceId
const name = ds.name
// Start to connect bluetooth device
wx.createBLEConnection({
deviceId,
success: (res) = > {
this.setData({
connected: true,
name,
deviceId,
})
this.getBLEDeviceServices(deviceId)
}
})
// Stop searching for Bluetooth after the bluetooth device is connected.
this.stopBluetoothDevicesDiscovery()
}
Copy the codeStop searching for Bluetooth devices
StopBluetoothDevicesDiscovery: after the bluetooth connection is successful, need to stop search the bluetooth devices.
stopBluetoothDevicesDiscovery() {
wx.stopBluetoothDevicesDiscovery()
}
Copy the codeMonitor the connection status of bluetooth devices
OnBLEConnectionStateChange: monitored bluetooth connection status, including the loss of a bluetooth device, disconnect, can be processed in this method the abnormal situation happened after connection.
wx.onBLEConnectionStateChange(function (res) {
// This method can be used to handle exceptions such as unexpected disconnections
console.log(`device ${res.deviceId} state has changed, connected: ${res.connected}`)})Copy the codeObtain bluetooth device services
After connecting to the Bluetooth device, we still want to communicate with the Bluetooth device, or read data from the Bluetooth device, or write data to the Bluetooth device. First, you need to obtain the service information of the Bluetooth device.
getBLEDeviceServices(deviceId) {
// Get the service information of the Bluetooth device.
wx.getBLEDeviceServices({
deviceId,
success: (res) = > {
for (let i = 0; i < res.services.length; i++) {
if (res.services[i].isPrimary) {
// Get the eigenvalue of the Bluetooth device
this.getBLEDeviceCharacteristics(deviceId, res.services[i].uuid)
return}}}})}Copy the codeGet the eigenvalue of the Bluetooth device
GetBLEDeviceCharacteristics: according to the bluetooth service information, can communicate with bluetooth for eigenvalues. Generally, the characteristic values of notify or indicate are true and read or write are true.
Enable notification on bluetooth devices
NotifyBLECharacteristicValueChange: enable notifications of bluetooth devices, this method requires the eigenvalues of the bluetooth device notify or indicate to true. Data changes of bluetooth devices can be monitored only when this function is enabled on the Bluetooth device.
Get bluetooth device data
OnBLECharacteristicValueChange: listening to the bluetooth device data changes, when a bluetooth device data changes, can obtain the data after the corresponding change. You need to enable the notification function of bluetooth device to use.
Write data to bluetooth device
WriteBLECharacteristicValue: write data to the bluetooth device, it is necessary to characteristic values of the write is true.
// Get the eigenvalue of the Bluetooth device
getBLEDeviceCharacteristics(deviceId, serviceId) {
wx.getBLEDeviceCharacteristics({
deviceId,
serviceId,
success: (res) = > {
console.log('getBLEDeviceCharacteristics success', res.characteristics)
for (let i = 0; i < res.characteristics.length; i++) {
let item = res.characteristics[i]
if (item.properties.read) {
// Read bluetooth device data
wx.readBLECharacteristicValue({
deviceId,
serviceId,
characteristicId: item.uuid,
})
}
if (item.properties.write) {
this.setData({
canWrite: true
})
this._deviceId = deviceId
this._serviceId = serviceId
this._characteristicId = item.uuid
// Write data to bluetooth device
this.writeBLECharacteristicValue()
}
if (item.properties.notify || item.properties.indicate) {
// Enable the notification function of the Bluetooth device to listen to the changes of bluetooth data
wx.notifyBLECharacteristicValueChange({
deviceId,
serviceId,
characteristicId: item.uuid,
state: true,
})
}
}
},
fail(res) {
console.error('getBLEDeviceCharacteristics', res)
}
})
// Monitor bluetooth device data changes
wx.onBLECharacteristicValueChange((characteristic) = > {
const idx = inArray(this.data.chs, 'uuid', characteristic.characteristicId)
const data = {}
if (idx === - 1) {
data[`chs[The ${this.data.chs.length}] `] = {
uuid: characteristic.characteristicId,
value: ab2hex(characteristic.value)
}
} else {
data[`chs[${idx}] `] = {
uuid: characteristic.characteristicId,
value: ab2hex(characteristic.value)
}
}
this.setData(data)
})
}
// Write data to bluetooth device
writeBLECharacteristicValue() {
// Send a 0x00 hexadecimal data to the Bluetooth device
let buffer = new ArrayBuffer(1)
let dataView = new DataView(buffer)
dataView.setUint8(0.Math.random() * 255 | 0)
wx.writeBLECharacteristicValue({
deviceId: this._deviceId,
serviceId: this._serviceId,
characteristicId: this._characteristicId,
value: buffer,
})
}
Copy the codeDisconnect the Bluetooth device
CloseBLEConnection: Disconnect from the Bluetooth device
closeBLEConnection() {
// Disconnect the Bluetooth device
wx.closeBLEConnection({
deviceId: this.data.deviceId
})
this.setData({
connected: false.chs: [].canWrite: false})},Copy the codeDisabling the Bluetooth Module
CloseBluetoothAdapter: When bluetooth is finished, close the Bluetooth module and release system resources.
// Disable the Bluetooth module
wx.closeBluetoothAdapter({
success(res) {
console.log(res)
}
})
Copy the code