我需要能够调用泛型类型的方法,以便可以从SensorDescBattery获得常量SENSOR_ID的值。我使用的方法称为getSensorId(),但是当我使用通用类型sensorDescBattery调用该函数时,它要求我为getSensorId()方法提供一个参数,但它没有一个参数。
我在下面介绍了SensorDescBattery类:
class SensorDescBattery: SensorDescSingleValue {
let SENSOR_ID : UInt64 = 0x0000000000000001 { get{ return SENSOR_ID}}
var sensorIdentifier: Int64 = 0x0000000000000001
var timestamp: UInt64
var batteryPercent: Float
var isCharging: Bool
var isUsbCharge: Bool
var isAcCharge: Bool
init(timestamp: UInt64, batteryPercent: Float, isCharging: Bool, isUsbCharge: Bool, isAcCharge: Bool) {
self.timestamp = timestamp
self.batteryPercent = batteryPercent;
self.isCharging = isCharging;
self.isUsbCharge = isUsbCharge;
self.isAcCharge = isAcCharge;
}
/*
override keyword always needed here
*/
required init(sensorData: SensorUploadSensorData) {
self.timestamp = sensorData.recordTime
self.batteryPercent = sensorData.valueFloat[0]
self.isCharging = sensorData.valueBool[0]
self.isUsbCharge = sensorData.valueBool[1]
self.isAcCharge = sensorData.valueBool[2]
}
init (battery: UIDevice, timestamp: UInt64) {
self.timestamp = timestamp
self.batteryPercent = battery.batteryLevel
if UIDeviceBatteryState.Charging.rawValue == 3{
self.isCharging = true
self.isUsbCharge = false
self.isAcCharge = true
}
else {
self.isCharging = false
self.isUsbCharge = false
self.isAcCharge = false
}
}
/*
Override keyword needed
*/
func toProtoSensor() -> SensorUploadSensorData {
let builder = SensorUploadSensorData.builder()
/*
Always set the record time! also it's important to put the values in the
array in the same exact order as in Android
*/
builder.recordTime = timestamp
builder.valueFloat = [self.batteryPercent]
builder.valueBool = [self.isCharging, self.isUsbCharge, self.isAcCharge]
return builder.build()
}
func getSensorId() -> UInt64 {
return SENSOR_ID;
}
func getValue() -> Float {
return self.batteryPercent;
}
}
这是QueryNumSingleValue类:
类QueryNumSingleValue {
var List : Array<SensorUploadSensorData>
func getSensorID() -> UInt64{
fatalError("Must Override")
}
init(from timestamp_from :UInt64,to timestamp_to : UInt64){
let vm = NervousVM()
self.List = vm.retrieve(0, fromTimeStamp: 0, toTimeStamp: 0)
self.List = vm.retrieve(getSensorID(), fromTimeStamp: timestamp_from, toTimeStamp: timestamp_to)
if(containsReading()){
println("retreived list of size /(getCount())")
}
}
func getCount() -> Int
{
return List.count
}
这是SensorDescSingleValue
protocol SensorDescSingleValue : SensorDesc {
func getValue() -> Float
}
我想做的是以下几点:
class SensorQueriesBattery<T : SensorDescBattery> : QueryNumSingleValue<SensorDescBattery>{
override func getSensorID() -> UInt64 {
return T.getSensorId()
}
}
但这不让我。我该如何进行?
编译器要求您提供一个参数,因为您在代码的这一部分中使用的是Class而不是对象来调用方法(并且该方法不是静态的):
override func getSensorID() -> UInt64 {
return T.getSensorId()
}
使代码与方法兼容的一种方法是:
class SensorQueriesBattery<T : SensorDescBattery> : QueryNumSingleValue{
var batteryDesc: T
init(desc:T) {
self.batteryDesc = desc
}
override func getSensorID() -> UInt64 {
return self.batteryDesc.getSensorId()
}
}
您必须在init中传递Generic对象才能调用该方法 getSensorId()
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