小程序蓝牙打印机实现连接和写入分开
时间: 2023-07-29 16:07:11 浏览: 54
小程序蓝牙打印机连接和写入可以分开实现,以下是一个简单的示例:
连接:
1. 引入 wx.createBLEConnection API,并创建一个变量存储连接状态:
```javascript
var connected = false;
var deviceId = 'xxxxxx'; // 打印机设备ID
```
2. 监听连接状态变化:
```javascript
wx.onBLEConnectionStateChange(function (res) {
console.log(`device ${res.deviceId} state has changed, connected: ${res.connected}`);
connected = res.connected;
})
```
3. 连接设备:
```javascript
wx.createBLEConnection({
deviceId: deviceId,
success: function(res) {
console.log('connect success:', res)
connected = true;
},
fail: function(res) {
console.log('connect fail:', res)
connected = false;
}
})
```
写入:
1. 引入 wx.writeBLECharacteristicValue API,并创建一个变量存储是否正在写入:
```javascript
var writing = false;
var serviceId = 'xxxxxx'; // 打印机服务ID
var characteristicId = 'xxxxxx'; // 打印机特征值ID
var buffer = new ArrayBuffer(20); // 写入的数据
```
2. 监听写入状态变化:
```javascript
wx.onBLECharacteristicValueChange(function(res) {
console.log('characteristic value:', res.value)
writing = false;
})
```
3. 写入数据:
```javascript
wx.writeBLECharacteristicValue({
deviceId: deviceId,
serviceId: serviceId,
characteristicId: characteristicId,
value: buffer,
success: function(res) {
console.log('write success:', res)
writing = true;
},
fail: function(res) {
console.log('write fail:', res)
writing = false;
}
})
```
需要注意的是,写入数据时要确保已经连接成功,并且不要频繁写入数据,否则会影响打印效果。