微信小程序蓝牙打印机demo

对于蓝牙有写入数据的话，需要时低功耗的蓝牙。向低功耗蓝牙设备特征值中写入二进制数据。注意：必须设备的特征值支持 write 才可以成功调用。

https://developers.weixin.qq.com/miniprogram/dev/api/device/bluetooth-ble/wx.writeBLECharacteristicValue.html

先搜索蓝牙设备

wxml

<button class="btn" type="primary" bindtap="startSearch" loading='{{isScanning}}'> 开始搜索 </button>
  <view  wx:for="{{list}}" wx:for-item="item" 
         data-title="{{item.deviceId}}" 
         data-name="{{item.name}}" 
         data-advertisData="{{item.advertisServiceUUIDs}}" 
         wx:key="{{item.deviceId}}"
         bindtap="bindViewTap">
      <view  class="item">
      <div class="deviceId block">{{item.deviceId}}</div>
      <div class="name block">{{item.name}}</div>
     </view>    
</view>  

js

app.BLEInformation.platform = getApp().getPlatform()

  data: {
    list: [],
    services: [],
    serviceId: 0,
    writeCharacter: false,
    readCharacter: false,
    notifyCharacter: false,
    isScanning:false
  },

  startSearch: function () {
    var that = this
    wx.openBluetoothAdapter({
      success: function (res) {
        wx.getBluetoothAdapterState({
          success: function (res) {
            if (res.available) {
              if (res.discovering) {
                wx.stopBluetoothDevicesDiscovery({
                  success: function (res) {
                    console.log(res)
                  }
                })
              }
              that.checkPemission()
            } else {
              wx.showModal({
                title: '提示',
                content: '本机蓝牙不可用',
              })
            }
          },
        })
      }, fail: function () {
        wx.showModal({
          title: '提示',
          content: '蓝牙初始化失败，请打开蓝牙',
        })
      }
    })
  },
  checkPemission: function () {  //android 6.0以上需授权地理位置权限
    var that = this
    var platform = app.BLEInformation.platform
    if (platform == "ios") {
      app.globalData.platform = "ios"
      that.getBluetoothDevices()
    } else if (platform == "android") {
      app.globalData.platform = "android"
      console.log(app.getSystem().substring(app.getSystem().length - (app.getSystem().length - 8), app.getSystem().length - (app.getSystem().length - 8) + 1))
      if (app.getSystem().substring(app.getSystem().length - (app.getSystem().length - 8), app.getSystem().length - (app.getSystem().length - 8) + 1) > 5) {
        wx.getSetting({
          success: function (res) {
            console.log(res)
            if (!res.authSetting['scope.userLocation']) {
              wx.authorize({
                scope: 'scope.userLocation',
                complete: function (res) {
                  that.getBluetoothDevices()
                }
              })
            } else {
              that.getBluetoothDevices()
            }
          }
        })
      }
    }
  },
  getBluetoothDevices: function () {  //获取蓝牙设备信息
    var that = this
    console.log("start search")
    wx.showLoading({
      title: '正在加载',
    })
    that.setData({
      isScanning:true
    })
    wx.startBluetoothDevicesDiscovery({
      success: function (res) {
        console.log(res)
        setTimeout(function () {
          wx.getBluetoothDevices({
            success: function (res) {
              var devices = []
              var num = 0
              for (var i = 0; i < res.devices.length; ++i) {
                if (res.devices[i].name != "未知设备") {
                  devices[num] = res.devices[i]
                  num++
                }
              }
              that.setData({
                list: devices,
                isScanning:false
              })
              wx.hideLoading()
              wx.stopPullDownRefresh()
            },
          })
        }, 3000)
      },
    })
  },
  bindViewTap: function (e) {
    var that = this
    wx.stopBluetoothDevicesDiscovery({
      success: function (res) { console.log(res) },
    })
    that.setData({
      serviceId: 0,
      writeCharacter: false,
      readCharacter: false,
      notifyCharacter: false
    })
    console.log(e.currentTarget.dataset.title)
    wx.showLoading({
      title: '正在连接',
    })
    wx.createBLEConnection({
      deviceId: e.currentTarget.dataset.title,
      success: function (res) {
        console.log(res)
        app.BLEInformation.deviceId = e.currentTarget.dataset.title
        that.getSeviceId()
      }, fail: function (e) {
        wx.showModal({
          title: '提示',
          content: '连接失败',
        })
        console.log(e)
        wx.hideLoading()
      }, complete: function (e) {
        console.log(e)
      }
    })
  },
  getSeviceId: function () {
    var that = this
    var platform = app.BLEInformation.platform
    console.log(app.BLEInformation.deviceId)
    wx.getBLEDeviceServices({
      deviceId: app.BLEInformation.deviceId,
      success: function (res) {
        console.log(res)
        that.setData({
          services: res.services
        })
        that.getCharacteristics()
      }, fail: function (e) {
        console.log(e)
      }, complete: function (e) {
        console.log(e)
      }
    })
  },
  getCharacteristics: function () {
    var that = this
    var list = that.data.services
    var num = that.data.serviceId
    var write = that.data.writeCharacter
    var read = that.data.readCharacter
    var notify = that.data.notifyCharacter
    wx.getBLEDeviceCharacteristics({
      deviceId: app.BLEInformation.deviceId,
      serviceId: list[num].uuid,
      success: function (res) {
        console.log(res)
        for (var i = 0; i < res.characteristics.length; ++i) {
          var properties = res.characteristics[i].properties
          var item = res.characteristics[i].uuid
          if (!notify) {
            if (properties.notify) {
              app.BLEInformation.notifyCharaterId = item
              app.BLEInformation.notifyServiceId = list[num].uuid
              notify = true
            }
          }
          if (!write) {
            if (properties.write) {
              app.BLEInformation.writeCharaterId = item
              app.BLEInformation.writeServiceId = list[num].uuid
              write = true
            }
          }
          if (!read) {
            if (properties.read) {
              app.BLEInformation.readCharaterId = item
              app.BLEInformation.readServiceId = list[num].uuid
              read = true
            }
          }
        }
        if (!write || !notify || !read) {
          num++
          that.setData({
            writeCharacter: write,
            readCharacter: read,
            notifyCharacter: notify,
            serviceId: num
          })
         if(num == list.length){
           wx.showModal({
             title: '提示',
             content: '找不到该读写的特征值',
           })
         }else{
           that.getCharacteristics()
         }
        } else {
          that.openControl()
        }
      }, fail: function (e) {
        console.log(e)
      }, complete: function (e) {
        console.log("write:"+app.BLEInformation.writeCharaterId)
        console.log("read:"+app.BLEInformation.readCharaterId)
        console.log("notify:"+app.BLEInformation.notifyCharaterId)
      }
    })
  },
  openControl: function () {
    wx.navigateTo({
      url: '../startPrint/startPrint',
    })
  },

然后打印

下面就是startPrint的代码
wxml

<view class="body">
  <textarea class="input" bindinput="inputEvent" />  
  <button type="primary" bindtap="sendData">发送(票据可使用)</button>  
   <button type='primary' bindtap='labelTest' loading='{{isLabelSend}}' disabled='{{isLabelSend}}'>标签测试</button>  
</view>  

下面是 js 的代码，首先是设置变量

data: {
    sendContent: "",
    looptime: 0,
    currentTime: 1,
    lastData: 0,
    oneTimeData: 0,
    returnResult: "returnResult",
    canvasWidth: 80,
    canvasHeight: 80,
    buffSize: [],
    buffIndex: 0,
    printNum: [],
    printNumIndex: 0,
    printerNum: 1,
    currentPrint: 1,
    isReceiptSend: false,
    isLabelSend: false
  },

command.setCls() ，需要设置这个，不然内容和上一次重复

onLoad: function(options) {
    var that = this;
    wx.notifyBLECharacteristicValueChange({
      deviceId: app.BLEInformation.deviceId,
      serviceId: app.BLEInformation.notifyServiceId,
      characteristicId: app.BLEInformation.notifyCharaterId,
      state: true,
      success: function(res) {
        wx.onBLECharacteristicValueChange(function(r) {
          console.log(`characteristic ${r.characteristicId} has changed, now is ${r}`)
        })
      },
      fail: function(e) {
        console.log('fail', e)
      },
      complete: function(e) {
        console.log('complete', e)
      }
    })
  },

  inputEvent: function(e) { 
    this.setData({
      sendContent: e.detail.value
    })
    console.log('sendContent: ', this.sendContent)
  },

  sendData: function() { 
    var data = this.data.sendContent + "\n"
    var that = this;
    var command = tsc.jpPrinter.createNew()
    command.setGap(0)
    command.setCls()
    command.setText(60, 90, "TSS24.BF2", 1, 1, data)
    command.setPagePrint()
    that.prepareSend(command.getData())
  },

  labelTest: function() { 
    var that = this;
    var canvasWidth = that.data.canvasWidth
    var canvasHeight = that.data.canvasHeight
    var command = tsc.jpPrinter.createNew()
    command.setSize(48, 40)
    command.setGap(0)
    command.setCls() //需要设置这个，不然内容和上一次重复
    command.setQR(1, 120, "L", 5, "A", "airenao.com")
    command.setText(60, 90, "TSS24.BF2", 1, 1, "成都爱热闹")
    command.setText(170, 50, "TSS24.BF2", 1, 1, "小程序测试")
    command.setText(170, 90, "TSS24.BF2", 1, 1, "测试数字12345678")
    command.setText(170, 120, "TSS24.BF2", 1, 1, "测试英文abcdefg")
    command.setText(170, 150, "TSS24.BF2", 1, 1, "测试符号/*-+!@#$")
    wx.canvasGetImageData({
      canvasId: 'edit_area_canvas',
      x: 0,
      y: 0,
      width: canvasWidth,
      height: canvasHeight,
      success: function(res) {
        command.setBitmap(60, 0, 0, res)
      },
      complete: function() {
        command.setPagePrint()
        that.setData({
          isLabelSend: true
        })
        that.prepareSend(command.getData())
      }
    })

  },

准备发送内容, printNum 这个是需要打印多少份，buff 是每次打印多少字节数

prepareSend: function(buff) { 
    console.log('buff', buff)
    var that = this
    var time = that.data.oneTimeData
    var looptime = parseInt(buff.length / time);
    var lastData = parseInt(buff.length % time);
    console.log(looptime + "---" + lastData)
    that.setData({
      looptime: looptime + 1,
      lastData: lastData,
      currentTime: 1,
    })
    that.Send(buff)
  },

  queryStatus: function() { //查询打印机状态
    var command = esc.jpPrinter.Query();
    command.getRealtimeStatusTransmission(1);
    this.setData({
      returnResult: "查询成功"
    })
  },

  Send: function(buff) { //分包发送
    var that = this
    var currentTime = that.data.currentTime
    var loopTime = that.data.looptime
    var lastData = that.data.lastData
    var onTimeData = that.data.oneTimeData
    var printNum = that.data.printerNum //打印多少份
    var currentPrint = that.data.currentPrint
    var buf
    var dataView
    if (currentTime < loopTime) {
      buf = new ArrayBuffer(onTimeData)
      dataView = new DataView(buf)
      for (var i = 0; i < onTimeData; ++i) {
        dataView.setUint8(i, buff[(currentTime - 1) * onTimeData + i])
      }
    } else {
      buf = new ArrayBuffer(lastData)
      dataView = new DataView(buf)
      for (var i = 0; i < lastData; ++i) {
        dataView.setUint8(i, buff[(currentTime - 1) * onTimeData + i])
      }
    }
    console.log("第" + currentTime + "次发送数据大小为：" + buf.byteLength)
    wx.writeBLECharacteristicValue({
      deviceId: app.BLEInformation.deviceId,
      serviceId: app.BLEInformation.writeServiceId,
      characteristicId: app.BLEInformation.writeCharaterId,
      value: buf,
      success: function(res) {
        console.log('写入成功', res)
      },
      fail: function(e) {
        console.fail('写入失败', e)
      },
      complete: function() {
        currentTime++
        if (currentTime <= loopTime) {
          that.setData({
            currentTime: currentTime
          })
          that.Send(buff)
        } else {
          wx.showToast({
            title: '已打印第' + currentPrint + '张',
          })
          if (currentPrint == printNum) {
            that.setData({
              looptime: 0,
              lastData: 0,
              currentTime: 1,
              isReceiptSend: false,
              isLabelSend: false,
              currentPrint: 1
            })
          } else {
            currentPrint++
            that.setData({
              currentPrint: currentPrint,
              currentTime: 1,
            })
            console.log("开始打印")
            that.Send(buff)
          }
        }
      }
    })
  },

最后的成品样子