#在藍牙連接的過程中部分api需要加定時器延時1秒到2秒左右再執行，原因為何不知道，小程序有這樣的要求
#1.首先是要初始化藍牙：openBluetoothAdapter()
```js
if (wx.openBluetoothAdapter) {
wx.openBluetoothAdapter({
success: function(res) {
/* 獲取本機的藍牙狀態 */
setTimeout(() => {
getBluetoothAdapterState()
}, 1000)
},
fail: function(err) {
// 初始化失敗
}
})
} else {
}
```
#2.檢測本機藍牙是否可用：
#? 要在上述的初始化藍牙成功之後回調裏調用
```js
getBluetoothAdapterState() {
var that= this;
that.toastTitle= '檢查藍牙狀態'
wx.getBluetoothAdapterState({
success: function(res) {
startBluetoothDevicesDiscovery()
},
fail(res) {
console.log(res)
}
})
}
```
#3. 開始搜索藍牙設備：
```js
startBluetoothDevicesDiscovery() {
var that= this;
setTimeout(() => {
wx.startBluetoothDevicesDiscovery({
success: function(res) {
/* 獲取藍牙設備列表 */
that.getBluetoothDevices()
},
fail(res) {
}
})
}, 1000)
}
```
#4. 獲取搜索到的藍牙設備列表
# /* that.deviceName 是獲取到的藍牙設備的名稱， 因為藍牙設備在安卓和蘋果手機上搜到的藍牙地址顯示是不壹樣的，所以根據設備名稱匹配藍牙*/
```js
getBluetoothDevices() {
var that= this;
setTimeout(() => {
wx.getBluetoothDevices({
services: [],
allowDuplicatesKey: false,
interval: 0,
success: function(res) {
if (res.devices.length> 0) {
if (JSON.stringify(res.devices).indexOf(that.deviceName) !== -1) {
for (let i = 0; i < res.devices.length; i++) {
if (that.deviceName === res.devices[i].name) {
/* 根據指定的藍牙設備名稱匹配到deviceId */
that.deviceId = that.devices[i].deviceId;
setTimeout(() => {
that.connectTO();
}, 2000);
};
};
} else {
}
} else {
}
},
fail(res) {
console.log(res, '獲取藍牙設備列表失敗=====')
}
})
}, 2000)
},
```
#5.連接藍牙
# 匹配到的藍牙設備ID 發送連接藍牙的請求， 連接成功之後 應該斷開藍牙搜索的api，然後去獲取所連接藍牙設備的service服務
```js
connectTO() {
wx.createBLEConnection({
deviceId: deviceId,
success: function(res) {
that.connectedDeviceId = deviceId;
/* 4.獲取連接設備的service服務 */
that.getBLEDeviceServices();
wx.stopBluetoothDevicesDiscovery({
success: function(res) {
console.log(res, '停止搜索')
},
fail(res) {
}
})
},
fail: function(res) {
}
})
}
```
#6. 獲取藍牙設備的service服務,獲取的serviceId有多個要試著連接最終確定哪個是穩定版本的service 獲取服務完後獲取設備特征值
```js
getBLEDeviceServices() {
setTimeout(() => {
wx.getBLEDeviceServices({
deviceId: that.connectedDeviceId,
success: function(res) {
that.services= res.services
/* 獲取連接設備的所有特征值 */
that.getBLEDeviceCharacteristics()
},
fail: (res) => {
}
})
}, 2000)
},
```
#7.獲取藍牙設備特征值
# 獲取到的特征值有多個，最後要用的事能讀，能寫，能監聽的那個值的uuid作為特征值id，
```js
getBLEDeviceCharacteristics() {
setTimeout(() => {
wx.getBLEDeviceCharacteristics({
deviceId: connectedDeviceId,
serviceId: services[2].uuid,
success: function(res) {
for (var i = 0; i < res.characteristics.length; i++) {
if ((res.characteristics[i].properties.notify || res.characteristics[i].properties.indicate) &&
(res.characteristics[i].properties.read && res.characteristics[i].properties.write)) {
console.log(res.characteristics[i].uuid, '藍牙特征值 ==========')
/* 獲取藍牙特征值 */
that.notifyCharacteristicsId = res.characteristics[i].uuid
// 啟用低功耗藍牙設備特征值變化時的 notify 功能
that.notifyBLECharacteristicValueChange()
}
}
},
fail: function(res) {
}
})
}, 1000)
},
```
#8.啟動notify 藍牙監聽功能 然後使用 wx.onBLECharacteristicValueChange用來監聽藍牙設備傳遞數據
#接收到的數據和發送的數據必須是二級制數據， 頁面展示的時候需要進行轉換
```js
notifyBLECharacteristicValueChange() { // 啟用低功耗藍牙設備特征值變化時的 notify 功能
var that= this;
console.log('6.啟用低功耗藍牙設備特征值變化時的 notify 功能')
wx.notifyBLECharacteristicValueChange({
state: true,
deviceId: that.connectedDeviceId,
serviceId: that.notifyServicweId,
characteristicId: that.notifyCharacteristicsId,
complete(res) {
/*用來監聽手機藍牙設備的數據變化*/
wx.onBLECharacteristicValueChange(function(res) {
/**/
that.balanceData += that.buf2string(res.value)
that.hexstr += that.receiveData(res.value)
})
},
fail(res) {
console.log(res, '啟用低功耗藍牙設備監聽失敗')
that.measuringTip(res)
}
})
},
/*轉換成需要的格式*/
buf2string(buffer) {
var arr = Array.prototype.map.call(new Uint8Array(buffer), x => x)
return arr.map((char, i) => {
return String.fromCharCode(char);
}).join('');
},
receiveData(buf) {
return this.hexCharCodeToStr(this.ab2hex(buf))
},
/*轉成二進制*/
ab2hex (buffer) {
? var hexArr = Array.prototype.map.call(
? new Uint8Array(buffer), function (bit) {
? return ('00' + bit.toString(16)).slice(-2)
}
)
? return hexArr.join('')
},
/*轉成可展會的文字*/
hexCharCodeToStr(hexCharCodeStr) {
? var trimedStr = hexCharCodeStr.trim();
? var rawStr = trimedStr.substr(0, 2).toLowerCase() === '0x' ? trimedStr.substr(2) : trimedStr;
? var len = rawStr.length;
? var curCharCode;
? var resultStr= [];
? for (var i = 0; i < len; i = i+ 2) {
? curCharCode = parseInt(rawStr.substr(i, 2), 16);
? resultStr.push(String.fromCharCode(curCharCode));
}
? return resultStr.join('');
},
```
# 向藍牙設備發送數據
```js
sendData(str) {
let that= this;
let dataBuffer = new ArrayBuffer(str.length)
let dataView = new DataView(dataBuffer)
for (var i = 0; i < str.length; i++) {
dataView.setUint8(i, str.charAt(i).charCodeAt())
}
let dataHex = that.ab2hex(dataBuffer);
this.writeDatas = that.hexCharCodeToStr(dataHex);
wx.writeBLECharacteristicValue({
deviceId: that.connectedDeviceId,
serviceId: that.notifyServicweId,
characteristicId: that.notifyCharacteristicsId,
value: dataBuffer,
success: function (res) {
console.log('發送的數據：' + that.writeDatas)
console.log('message發送成功')
},
fail: function (res) {
},
complete: function (res) {
}
})
},
```
# 當不需要連接藍牙了後就要關閉藍牙，並關閉藍牙模塊
```js
// 斷開設備連接
closeConnect() {
if (that.connectedDeviceId) {
wx.closeBLEConnection({
deviceId: that.connectedDeviceId,
success: function(res) {
that.closeBluetoothAdapter()
},
fail(res) {
}
})
} else {
that.closeBluetoothAdapter()
}
},
// 關閉藍牙模塊
closeBluetoothAdapter() {
wx.closeBluetoothAdapter({
success: function(res) {
},
fail: function(err) {
}
})
},
```
#在向藍牙設備傳遞數據和接收數據的過程中，並未使用到read的API 不知道有沒有潛在的問題，目前線上運行為發現任何的問題
#今天的藍牙使用心得到此結束，謝謝