我正在开发一个 react-native 应用程序，它可以获取支持蓝牙的秤（MI SCALE2）的重量值。（我对蓝牙一无所知。）
// 版本
“反应原生”：“0.66.1”，
“react-native-ble-plx”：“https://github.com/below/react-native-ble-plx”，
当我上秤时，我能够得到这些值。
# feature
{"data": [33, 0, 0, 0], "type": "Buffer"}
# Weight
{"data": [2, 156, 74, 178, 7, 1, 7, 22, 33, 1], "type": "Buffer"}
{"data": [2, 156, 74, 178, 7, 1, 7, 22, 33, 1], "type": "Buffer"}
{"data": [2, 156, 74, 178, 7, 1, 7, 22, 33, 1], "type": "Buffer"}
{"data": [2, 156, 74, 178, 7, 1, 7, 22, 33, 2], "type": "Buffer"}
{"data": [2, 156, 74, 178, 7, 1, 7, 22, 33, 2], "type": "Buffer"}
{"data": [34, 156, 74, 178, 7, 1, 7, 22, 33, 2], "type": "Buffer"}
{"data": [162, 156, 74, 178, 7, 1, 7, 22, 33, 6], "type": "Buffer"}
看了几个地方的Q&A，才知道需要把特征的值和权重数组的值结合起来。
我想知道如何从我的结果中获取重量值，例如“94.9kg，95.5kg，...”
下面是我写的代码。
manager.startDeviceScan(null, null, (error, device) => {
if (error) {
console.log('error : ' + error);
return;
}
console.log(device.name);
if (device.name === 'MI SCALE2') {
console.log('detected!!');
manager.stopDeviceScan();
device
.connect()
.then(device => {
return device.discoverAllServicesAndCharacteristics();
})
.then(device => {
return device.services();
})
.then(services => {
const result = services.filter(id => id.uuid.indexOf('181d') != -1); // 181d is Weight Scale -> org.bluetooth.service.weight_scale;
return result[0].characteristics();
})
.then(characters => {
const resultDateObject = characters.filter(
data => data.uuid.indexOf('2a2b') != -1, // 2a2b is Current Time -> org.bluetooth.characteristic.current_time;
);
const resultWeightFeature = characters.filter(
data => data.uuid.indexOf('2a9e') != -1, // 2a9e is Weight Scale Feature -> org.bluetooth.characteristic.weight_scale_feature
);
const resultWeight = characters.filter(
data => data.uuid.indexOf('2a9d') != -1, // 2a9d is Weight Measurement -> org.bluetooth.characteristic.weight_measurement;
);
const resultPosition2D = characters.filter(
data => data.uuid.indexOf('2a2f') != -1, // 2a2f is Position 2D -> org.bluetooth.characteristic.position_2d;
);
// const DeviceID = resultWeightFeature[0].deviceID;
// const ServiceUUID = resultWeightFeature[0].serviceUUID;
// const DateCharacterUUID = resultDateObject[0].uuid;
// const WeightFeatureCharacterUUID = resultWeightFeature[0].uuid;
// const WeightCharacterUUID = resultWeight[0].uuid;
// const PositionCharacterUUID = resultPosition2D[0].uuid;
resultWeight[0].monitor((error, characteristic) => {
if (error) {
console.log('error:::::', error);
return;
}
let your_bytes = Buffer.from(characteristic.value, "base64");
console.log(your_bytes);
})
return resultWeightFeature[0].read();
}).then(feature => {
let feature_bytes = Buffer.from(feature.value, "base64");
console.log('feature.value');
console.log(feature_bytes);
})
}
});