首页 文章

在Core Bluetooth Framework中创建Writable特性的问题

提问于
浏览 次
4

我是Core Bluetooth Framework的新手 . 我正在开发一个充当外围设备的应用程序 . 我需要应用程序通知特定值到订阅的中心，并且还通过连接的中心写出特征值 . 我在创建它时设置了特征值 . 问题是当我设置要通知或写入的特性属性时显示错误“具有缓存值的特征必须是只读的” . 有谁能够帮我 ？

var charValue = characteristicDetail["value"] as String
 var charProperties:CBCharacteristicProperties = getProperty(characteristicDetail["properties"] as String )
 let data = charValue.dataUsingEncoding(NSUTF8StringEncoding)
 var characteristic = CBMutableCharacteristic(type: charId, properties: charProperties, value: data, permissions: CBAttributePermissions.Readable)



func getProperty(string:String) -> CBCharacteristicProperties
    {
    var propertyString:CBCharacteristicProperties?
    switch string{
    case "r","R":
        propertyString = CBCharacteristicProperties.Read
    case "w","W":
        propertyString = CBCharacteristicProperties.Write
    case "n","N":
        propertyString = CBCharacteristicProperties.Notify
    case "i","I":
        propertyString = CBCharacteristicProperties.Indicate
    case "rw","wr","WR","RW":
        propertyString = CBCharacteristicProperties.Read|CBCharacteristicProperties.Write
    case "rn","nr","NR","RN":
        propertyString = CBCharacteristicProperties.Read|CBCharacteristicProperties.Notify
    case "wn","nw","NW","WN":
        propertyString = CBCharacteristicProperties.Write|CBCharacteristicProperties.Notify
    default:
        propertyString = CBCharacteristicProperties.Read
    }
    return propertyString!

}
ios swift bluetooth core-bluetooth

2 回答

  • 0

    如果在创建 CBMutableCharacteristic 时指定了非零 value ，那么它是'cached characteristic'，并且如错误消息所示，您以后无法更改该值 .

    从 CBMutableCharacteristic init 方法的文档 -

    value - 要缓存的特征值 . 如果为零，则该值为动态值，将根据需要进行请求 .

    创建 CBMutableCharacteristic 时指定 nil - 在 didReceiveReadRequest CBPeripheralManagerDelegate 方法中请求时提供值 .

    如果您有已订阅特征的中心，那么每当值发生变化时，您也应该在 CBPeripheralManager 上调用 updateValue .

    请务必阅读Core Bluetooth Programming Guide中执行常见外设角色任务一节

    回复于
  • 8

    我找到了一个坚实的帖子中，在BLE方面包含了大量用于不同任务的优秀片段：

    创建服务：

    let serviceUUID = CBUUID(string: kServiceUUID)
let service = CBMutableService(type: serviceUUID, primary: true)

    创造特色：

    let characteristicUUID = CBUUID(string: kCharacteristicUUID)
let properties: CBCharacteristicProperties = [.Notify, .Read, .Write]
let permissions: CBAttributePermissions = [.Readable, .Writeable]
let characteristic = CBMutableCharacteristic(
    type: characteristicUUID,
    properties: properties,
    value: nil,
    permissions: permissions)

    为服务添加特征：

    service.characteristics = [characteristic1, characteristic2]

    将服务添加到外围设备管理器：

    peripheralManager.addService(service)

    Source

    回复于

相关问题