这里给大家分享我在网上总结出来的一些知识，希望对大家有所帮助
说明
基于uni-app开发，调用官方蓝牙相关api实现连接蓝牙与向蓝牙热敏打印机发送字节流，可打印文字，二维码，图片，调整字体大小等，本文提供大概思路
结构
- bluetooth.js 蓝牙连接相关模块封装
- commands.js 打印十六进制相关代码库
- gbk.js 编码转换库地址
- printerjobs.js 打印实现库
bluetooth.js
蓝牙连接相关封装代码
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 | class Bluetooth { constructor() { this.isOpenBle = false; this.deviceId = ""; this.serviceId = ""; this.writeId = ""; this.notifyId = ""; this.BluetoothConnectStatus = false this.printStatus = false this.init() } init() { this.closeBluetoothAdapter().then(() = >{ console.log("init初始关闭蓝牙模块") this.openBluetoothAdapter().then(() = >{ console.log("init初始化蓝牙模块") this.reconnect() //自动连接蓝牙设备 }) }) } showToast(title) { uni.showToast({ title: title, icon: 'none', 'duration': 2000 }); } openBluetoothAdapter() { return new Promise((resolve, reject) = >{ uni.openBluetoothAdapter({ success: res = >{ this.isOpenBle = true; resolve(res); }, fail: err = >{ this.showToast(`蓝牙未打开`); reject(err); }, }); }); } startBluetoothDevicesDiscovery() { if (!this.isOpenBle) { this.showToast(`初始化蓝牙模块失败`) return; } let self = this; uni.showLoading({ title: '蓝牙搜索中' }) return new Promise((resolve, reject) = >{ setTimeout(() = >{ uni.startBluetoothDevicesDiscovery({ success: res = >{ resolve(res) }, fail: res = >{ self.showToast(`搜索设备失败` + JSON.stringify(err)); reject(err); } }) }, 300); }); } stopBluetoothDevicesDiscovery() { let self = this; return new Promise((resolve, reject) = >{ uni.stopBluetoothDevicesDiscovery({ success: e = >{ uni.hideLoading(); }, fail: e = >{ uni.hideLoading(); self.showToast(`停止搜索蓝牙设备失败` + JSON.stringify(err)); } }) }); } createBLEConnection() { //设备deviceId let deviceId = this.deviceId; let self = this; // uni.showLoading({ // mask: true, // title: '设别连接中,请稍候...' // }) console.log(this.deviceId); return new Promise((resolve, reject) = >{ uni.createBLEConnection({ deviceId, success: (res) = >{ console.log("res:createBLEConnection " + JSON.stringify(res)); resolve(res) }, fail: err = >{ uni.hideLoading(); self.showToast(`停止搜索蓝牙设备失败` + JSON.stringify(err)); reject(err); } }) }); } //获取蓝牙设备所有服务(service) getBLEDeviceServices() { let _serviceList = []; let deviceId = this.deviceId; let self = this; return new Promise((resolve, reject) = >{ setTimeout(() = >{ uni.getBLEDeviceServices({ deviceId, success: res = >{ for (let service of res.services) { if (service.isPrimary) { _serviceList.push(service); } } uni.hideLoading(); console.log("_serviceList: " + JSON.stringify(_serviceList)); resolve(_serviceList) }, fail: err = >{ uni.hideLoading(); // self.showToast(`获取设备Services` + JSON.stringify(err)); reject(err); }, }) }, 500); }); } //获取蓝牙设备某个服务中所有特征值(characteristic) getBLEDeviceCharacteristics() { // console.log("getBLEDeviceCharacteristics") let deviceId = this.deviceId; let serviceId = this.serviceId; let self = this; return new Promise((resolve, reject) = >{ uni.getBLEDeviceCharacteristics({ deviceId, serviceId, success: res = >{ for (let _obj of res.characteristics) { //获取notify if (_obj.properties.notify) { self.notifyId = _obj.uuid; uni.setStorageSync('notifyId', self.notifyId); } //获取writeId if (_obj.properties.write) { self.writeId = _obj.uuid; uni.setStorageSync('writeId', self.writeId); } } //console.log("res:getBLEDeviceCharacteristics " + JSON.stringify(res)); let result = { 'notifyId': self.notifyId, 'writeId': self.writeId }; // self.showToast(`获取服务中所有特征值OK,${JSON.stringify(result)}`); this.BluetoothStatus = true resolve(result) }, fail: err = >{ self.showToast(`getBLEDeviceCharacteristics` + JSON.stringify(err)); reject(err); } }) }); } //断开联链接 closeBLEConnection() { let deviceId = this.deviceId; uni.closeBLEConnection({ deviceId, success(res) { console.log("closeBLEConnection" + res) } }) } notifyBLECharacteristicValue() { let deviceId = this.deviceId; let serviceId = this.serviceId; let characteristicId = this.notifyId; uni.notifyBLECharacteristicValueChange({ state: true, // 启用 notify 功能 deviceId, serviceId, characteristicId, success(res) { uni.onBLECharacteristicValueChange(function(res) { console.log('onBLECharacteristicValueChange', res); }); }, fail(res) { console.log('notifyBLECharacteristicValueChange failed:' + res.errMsg); } }); } writeBLECharacteristicValue(buffer) { let deviceId = this.deviceId; let serviceId = this.serviceId; let characteristicId = this.writeId; // console.log(deviceId); // console.log(serviceId); // console.log(characteristicId); return new Promise((resolve, reject) = >{ uni.writeBLECharacteristicValue({ deviceId, serviceId, characteristicId, value: buffer, success(res) { // console.log('message发送成功', JSON.stringify(res)); resolve(res); }, fail(err) { // console.log('message发送失败', JSON.stringify(err)); reject(err); } }); }); } closeBluetoothAdapter() { return new Promise((resolve, reject) = >{ uni.closeBluetoothAdapter({ success: res = >{ resolve() } }); }) } //若APP在之前已有搜索过某个蓝牙设备，并成功建立连接，可直接传入之前搜索获取的 deviceId 直接尝试连接该设备，无需进行搜索操作。 reconnect() { (async() = >{ try { this.deviceId = this.deviceId || uni.getStorageSync("deviceId"); this.serviceId = this.serviceId || uni.getStorageSync("serviceId"); console.log("this.deviceId", this.deviceId) console.log("this.serviceId", this.serviceId) let result1 = await this.createBLEConnection(); console.log("createBLEConnection: " + JSON.stringify(result1)); let result2 = await this.getBLEDeviceServices(); console.log("getBLEDeviceServices: " + JSON.stringify(result2)); let result3 = await this.getBLEDeviceCharacteristics(); console.log("getBLEDeviceCharacteristics: " + JSON.stringify(result3)); this.BluetoothConnectStatus = true this.showToast("蓝牙打印设备连接成功") // this.writeId = uni.getStorageSync("writeId"); // this.notifyId = uni.getStorageSync("notifyId"); } catch(err) { console.log("err: " + err); // this.showToast("蓝牙打印设备连接失败") } })(); }}exportdefault Bluetooth; |
commands.js
打印机ESC/POS十六进制编码库
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 | /** * 修改自https://github.com/song940/node-escpos/blob/master/commands.js * ESC/POS _ (Constants) */var _ = { LF: [0x0a], FS: [0x1c], FF: [0x0c], GS: [0x1d], DLE: [0x10], EOT: [0x04], NUL: [0x00], ESC: [0x1b], EOL: '\n',};/** * [FEED_CONTROL_SEQUENCES Feed control sequences] * @type {Object} */_.FEED_CONTROL_SEQUENCES = { CTL_LF: [0x0a], // Print and line feed CTL_GLF: [0x4a, 0x00], // Print and feed paper (without spaces between lines) CTL_FF: [0x0c], // Form feed CTL_CR: [0x0d], // Carriage return CTL_HT: [0x09], // Horizontal tab CTL_VT: [0x0b], // Vertical tab};_.CHARACTER_SPACING = { CS_DEFAULT: [0x1b, 0x20, 0x00], CS_SET: [0x1b, 0x20]};_.LINE_SPACING = { LS_DEFAULT: [0x1b, 0x32], LS_SET: [0x1b, 0x33]};/** * [HARDWARE Printer hardware] * @type {Object} */_.HARDWARE = { HW_INIT: [0x1b, 0x40], // Clear data in buffer and reset modes HW_SELECT: [0x1b, 0x3d, 0x01], // Printer select HW_RESET: [0x1b, 0x3f, 0x0a, 0x00], // Reset printer hardware Print:[0x1b, 0x64,0x01] //Print and feed paper};/** * [CASH_DRAWER Cash Drawer] * @type {Object} */_.CASH_DRAWER = { CD_KICK_2: [0x1b, 0x70, 0x00], // Sends a pulse to pin 2 [] CD_KICK_5: [0x1b, 0x70, 0x01], // Sends a pulse to pin 5 []};/** * [MARGINS Margins sizes] * @type {Object} */_.MARGINS = { BOTTOM: [0x1b, 0x4f], // Fix bottom size LEFT: [0x1b, 0x6c], // Fix left size RIGHT: [0x1b, 0x51], // Fix right size};/** * [PAPER Paper] * @type {Object} */_.PAPER = { PAPER_FULL_CUT: [0x1d, 0x56, 0x00], // Full cut paper PAPER_PART_CUT: [0x1d, 0x56, 0x01], // Partial cut paper PAPER_CUT_A: [0x1d, 0x56, 0x41], // Partial cut paper PAPER_CUT_B: [0x1d, 0x56, 0x42], // Partial cut paper};/** * [TEXT_FORMAT Text format] * @type {Object} */_.TEXT_FORMAT = { TXT_NORMAL: [0x1b, 0x21, 0x00], // Normal text TXT_2HEIGHT: [0x1b, 0x21, 0x10], // Double height text TXT_2WIDTH: [0x1b, 0x21, 0x20], // Double width text TXT_4SQUARE: [0x1b, 0x21, 0x30], // Double width & height text TXT_UNDERL_OFF: [0x1b, 0x2d, 0x00], // Underline font OFF TXT_UNDERL_ON: [0x1b, 0x2d, 0x01], // Underline font 1-dot ON TXT_UNDERL2_ON: [0x1b, 0x2d, 0x02], // Underline font 2-dot ON TXT_BOLD_OFF: [0x1b, 0x45, 0x00], // Bold font OFF TXT_BOLD_ON: [0x1b, 0x45, 0x01], // Bold font ON TXT_ITALIC_OFF: [0x1b, 0x35], // Italic font ON TXT_ITALIC_ON: [0x1b, 0x34], // Italic font ON TXT_FONT_A: [0x1b, 0x4d, 0x00], // Font type A TXT_FONT_B: [0x1b, 0x4d, 0x01], // Font type B TXT_FONT_C: [0x1b, 0x4d, 0x02], // Font type C TXT_ALIGN_LT: [0x1b, 0x61, 0x00], // Left justification TXT_ALIGN_CT: [0x1b, 0x61, 0x01], // Centering TXT_ALIGN_RT: [0x1b, 0x61, 0x02], // Right justification};/** * [BARCODE_FORMAT Barcode format] * @type {Object} */_.BARCODE_FORMAT = { BARCODE_TXT_OFF: [0x1d, 0x48, 0x00], // HRI barcode chars OFF BARCODE_TXT_ABV: [0x1d, 0x48, 0x01], // HRI barcode chars above BARCODE_TXT_BLW: [0x1d, 0x48, 0x02], // HRI barcode chars below BARCODE_TXT_BTH: [0x1d, 0x48, 0x03], // HRI barcode chars both above and below BARCODE_FONT_A: [0x1d, 0x66, 0x00], // Font type A for HRI barcode chars BARCODE_FONT_B: [0x1d, 0x66, 0x01], // Font type B for HRI barcode chars BARCODE_HEIGHT: function (height) { // Barcode Height [1-255] return [0x1d, 0x68, height]; }, BARCODE_WIDTH: function (width) { // Barcode Width [2-6] return [0x1d, 0x77, width]; }, BARCODE_HEIGHT_DEFAULT: [0x1d, 0x68, 0x64], // Barcode height default:100 BARCODE_WIDTH_DEFAULT: [0x1d, 0x77, 0x01], // Barcode width default:1 BARCODE_UPC_A: [0x1d, 0x6b, 0x00], // Barcode type UPC-A BARCODE_UPC_E: [0x1d, 0x6b, 0x01], // Barcode type UPC-E BARCODE_EAN13: [0x1d, 0x6b, 0x02], // Barcode type EAN13 BARCODE_EAN8: [0x1d, 0x6b, 0x03], // Barcode type EAN8 BARCODE_CODE39: [0x1d, 0x6b, 0x04], // Barcode type CODE39 BARCODE_ITF: [0x1d, 0x6b, 0x05], // Barcode type ITF BARCODE_NW7: [0x1d, 0x6b, 0x06], // Barcode type NW7 BARCODE_CODE93: [0x1d, 0x6b, 0x48], // Barcode type CODE93 BARCODE_CODE128: [0x1d, 0x6b, 0x49], // Barcode type CODE128};/** * [IMAGE_FORMAT Image format] * @type {Object} */_.IMAGE_FORMAT = { S_RASTER_N: [0x1d, 0x76, 0x30, 0x00], // Set raster image normal size S_RASTER_2W: [0x1d, 0x76, 0x30, 0x01], // Set raster image double width S_RASTER_2H: [0x1d, 0x76, 0x30, 0x02], // Set raster image double height S_RASTER_Q: [0x1d, 0x76, 0x30, 0x03], // Set raster image quadruple};/** * [BITMAP_FORMAT description] * @type {Object} */_.BITMAP_FORMAT = { BITMAP_S8: [0x1b, 0x2a, 0x00], BITMAP_D8: [0x1b, 0x2a, 0x01], BITMAP_S24: [0x1b, 0x2a, 0x20], BITMAP_D24: [0x1b, 0x2a, 0x21]};/** * [GSV0_FORMAT description] * @type {Object} */_.GSV0_FORMAT = { GSV0_NORMAL: [0x1d, 0x76, 0x30, 0x00], GSV0_DW: [0x1d, 0x76, 0x30, 0x01], GSV0_DH: [0x1d, 0x76, 0x30, 0x02], GSV0_DWDH: [0x1d, 0x76, 0x30, 0x03]};/** * [BEEP description] * @type {string} */_.BEEP = [0x1b, 0x42]; // Printer Buzzer pre hex/** * [COLOR description] * @type {Object} */_.COLOR = { 0: [0x1b, 0x72, 0x00], // black 1: [0x1b, 0x72, 0x01] // red};/** * [exports description] * @type {[type]} */module.exports = _; |
printerjobs.js
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 | const commands = require('./commands');const gbk = require('./gbk');const printerJobs = function() { this._queue = Array.from(commands.HARDWARE.HW_INIT); this._enqueue = function(cmd) { this._queue.push.apply(this._queue, cmd); }};/** * 增加打印内容 * @param {string} content 文字内容 */printerJobs.prototype.text = function(content) { if (content) { let uint8Array = gbk.encode(content); let encoded = Array.from(uint8Array); this._enqueue(encoded); } return this;};/** * 打印文字 * @param {string} content 文字内容 */printerJobs.prototype.print = function(content) { this.text(content); // this._enqueue(commands.LF); return this;};printerJobs.prototype.printL = function(content) { this.text(content); this._enqueue(commands.LF); return this;};printerJobs.prototype.printImage = function(content) { if (content) { const cmds = [].concat([29, 118, 48, 0], content); // console.log("cmds",cmds) this._enqueue(cmds); this._enqueue(commands.LF); } return this;};/** * 打印文字并换行 * @param {string} content 文字内容 */printerJobs.prototype.println = function(content = '') { return this.print(content + commands.EOL);};/** * 设置对齐方式 * @param {string} align 对齐方式 LT/CT/RT */printerJobs.prototype.setAlign = function(align) { this._enqueue(commands.TEXT_FORMAT['TXT_ALIGN_' + align.toUpperCase()]); return this;};/** * 设置字体 * @param {string} family A/B/C */printerJobs.prototype.setFont = function(family) { this._enqueue(commands.TEXT_FORMAT['TXT_FONT_' + family.toUpperCase()]); return this;};/** * 设定字体尺寸 * @param {number} width 字体宽度 1~2 * @param {number} height 字体高度 1~2 */printerJobs.prototype.setSize = function(width, height) { if (2 >= width && 2 >= height) { this._enqueue(commands.TEXT_FORMAT.TXT_NORMAL); if (2 === width && 2 === height) { this._enqueue(commands.TEXT_FORMAT.TXT_4SQUARE); } else if (1 === width && 2 === height) { this._enqueue(commands.TEXT_FORMAT.TXT_2HEIGHT); } else if (2 === width && 1 === height) { this._enqueue(commands.TEXT_FORMAT.TXT_2WIDTH); } } return this;};/** * 设定字体是否加粗 * @param {boolean} bold */printerJobs.prototype.setBold = function(bold) { if (typeof bold !== 'boolean') { bold = true; } this._enqueue(bold ? commands.TEXT_FORMAT.TXT_BOLD_ON : commands.TEXT_FORMAT.TXT_BOLD_OFF); return this;};/** * 设定是否开启下划线 * @param {boolean} underline */printerJobs.prototype.setUnderline = function(underline) { if (typeof underline !== 'boolean') { underline = true; } this._enqueue(underline ? commands.TEXT_FORMAT.TXT_UNDERL_ON : commands.TEXT_FORMAT.TXT_UNDERL_OFF); return this;};/** * 设置行间距为 n 点行,默认值行间距是 30 点 * @param {number} n 0≤n≤255 */printerJobs.prototype.setLineSpacing = function(n) { if (n === undefined || n === null) { this._enqueue(commands.LINE_SPACING.LS_DEFAULT); } else { this._enqueue(commands.LINE_SPACING.LS_SET); this._enqueue([n]); } return this;};/** * 打印空行 * @param {number} n */printerJobs.prototype.lineFeed = function(n = 1) { return this.print(new Array(n).fill(commands.EOL).join(''));};/** * 设置字体颜色，需要打印机支持 * @param {number} color - 0 默认颜色黑色 1 红色 */printerJobs.prototype.setColor = function(color) { this._enqueue(commands.COLOR[color === 1 ? 1 : 0]); return this;};/** * https://support.loyverse.com/hardware/printers/use-the-beeper-in-a-escpos-printers * 蜂鸣警报，需要打印机支持 * @param {number} n 蜂鸣次数,1-9 * @param {number} t 蜂鸣长短,1-9 */printerJobs.prototype.beep = function(n, t) { this._enqueue(commands.BEEP); this._enqueue([n, t]); return this;};/** * 清空任务 */printerJobs.prototype.clear = function() { this._queue = Array.from(commands.HARDWARE.HW_RESET); // this._enqueue(commands.HARDWARE.Print); return this;};/** * 返回ArrayBuffer */printerJobs.prototype.buffer = function() { return new Uint8Array(this._queue).buffer;};module.exports = printerJobs; |
代码实现
封装蓝牙连接，搜索，断开相关操作模块
蓝牙搜索
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | startBluetoothDeviceDiscovery() { let self = this; self.tempDeviceList = []; uni.startBluetoothDevicesDiscovery({ success: res = >{ uni.onBluetoothDeviceFound(devices = >{ // console.log("发现设备: " + JSON.stringify(devices)); if (!self.tempDeviceList.some(item = >{ return item.deviceId === devices.devices[0].deviceId || item.name === devices.devices[0].name })) { // console.log("new", devices.devices) self.tempDeviceList.push(devices.devices[0]) } }); this.connect = false this.$refs.popup.open() }, fail: err = >{ uni.showToast({ title: '搜索设备失败' + JSON.stringify(err), icon: 'none' }) } })}, |
搜索完成选择设备
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | async select_deviceId(item) { this.deviceId = item.deviceId; this.$bluetooth.deviceId = item.deviceId; uni.setStorageSync('deviceId', this.$bluetooth.deviceId); this.serviceList = []; try { //1.链接设备 let result = await this.$bluetooth.createBLEConnection(); //2.寻找服务 let result2 = null setTimeout(async() = >{ result2 = await this.$bluetooth.getBLEDeviceServices(); console.log("获取服务: " + JSON.stringify(result2)); this.serviceList = result2; console.log("serviceList", this.serviceList.length) if (this.serviceList[2].uuid) { this.select_service(this.serviceList[2].uuid) } else { uni.showToast({ title: '不是打印设备', icon: 'none' }) } }, 1000) } catch(e) { //TODO handle the exception console.log("e: " + JSON.stringify(e)); }}, |
选中服务
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | async select_service(res) { console.log("select_service", res) this.$bluetooth.serviceId = res; console.log("this.$bluetooth.serviceId", this.$bluetooth.serviceId) uni.setStorageSync('serviceId', res); try { let result = await this.$bluetooth.getBLEDeviceCharacteristics(); console.log("resultresult", result) this.$refs.popup.close() uni.showToast({ title: "连接成功" }) // this.pickUpOnce() } catch(e) { //TODO handle the exception console.log("e: " + JSON.stringify(e)); }}, |
打印内容组合
1 2 3 4 5 6 7 8 9 10 11 12 | async writeBLECharacteristicValueTongzhishu() { let Qrcode_res = await this.get_Qrcode() let sign = await this.getSign() console.log("sign") let printerJobs = new PrinterJobs() let p = printerJobs.setAlign('ct') .setBold(true) .printL("打印测试") let buffer = printerJobs.buffer(); this.printbuffs(buffer);}, |
打印内容组合
主要是实现打印编码推送循环，手机蓝牙可能出现编码发送失败情况，这个时候就是要循环保证每个字节准确推送
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | printbuffs(buffer, fun) { console.log("printbuffs", buffer.byteLength) const maxChunk = 8; let p = Promise.resolve(); for (let i = 0, j = 0, length = buffer.byteLength; i < length; i += maxChunk, j++) { let subPackage = buffer.slice(i, i + maxChunk <= length ? (i + maxChunk) : length); p = p.then(() = >{ if (i == 0) { this.$bluetooth.printStatus = true this.$refs.loading.open(); } if ((i + maxChunk) >= length) { console.log("printEnd") setTimeout(() = >{ this.$bluetooth.printStatus = false this.$refs.loading.close(); }, 1000) } return this.printbuff(subPackage) }) } p = p.then(() = >{ console.log("printEve") fun() })},async printbuff(buffer) { while (true) { try { await this.$bluetooth.writeBLECharacteristicValue(buffer); break; } catch(e) {} }}, |
本文转载于:
https://juejin.cn/post/7001752261722537991
如果对您有所帮助，欢迎您点个关注，我会定时更新技术文档，大家一起讨论学习，一起进步。
__EOF__
