我正试图从找到的CBService中读取CBCharacteristic值,并不断得到错误
fatal error: unexpectedly found nil while unwrapping an Optional value
我的代码如下
func peripheral(peripheral: CBPeripheral!, didDiscoverCharacteristicsForService service: CBService!, error: NSError!)
{
for characteristic in service.characteristics as! [CBCharacteristic]
{
peripheral.readValueForCharacteristic(characteristic)
}
}
检查以确保CBService不是nil,并且看起来是健全的。有没有人知道用什么正确的快捷方式来打开这个清单?
最佳答案
多谢狗粮!
func peripheral(peripheral: CBPeripheral!, didDiscoverCharacteristicsForService service: CBService!, error: NSError!)
{
if let characteristics = service.characteristics as? [CBCharacteristic]
{
for characteristic in characteristics
{
peripheral.readValueForCharacteristic(characteristic)
}
}
}
关于xcode - 在For In循环中展开 optional 值时意外发现nil,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/30370085/