当你得到centralManager的回调时状态已更改为 CBCentralManagerStatePoweredOff ，您需要遍历所有外围设备并在其上调用 cancelConnection：。那你就好了。

When you get the callback that the centralManager state has changed to CBCentralManagerStatePoweredOff, you need to loop through all your peripherals and call cancelConnection: on them. Then you'll be good to go.

[_yourCentralManager cancelPeripheralConnection:yourPeripheral];