Check Battery Level iOS Swift

Check Battery Level iOS Swift

Xcode 11 • Swift 5.1

First just enable battery monitoring:

UIDevice.current.isBatteryMonitoringEnabled = true

Then you can create a computed property to return the battery level:

Battery level ranges from 0.0 (fully discharged) to 1.0 (100%
charged). Before accessing this property, ensure that battery
monitoring is enabled. If battery monitoring is not enabled, battery
state is UIDevice.BatteryState.unknown and the value of this property
is –1.0.

var batteryLevel: Float { UIDevice.current.batteryLevel }

To monitor your device battery level you can add an observer for the UIDevice.batteryLevelDidChangeNotification:

NotificationCenter.default.addObserver(self, selector: #selector(batteryLevelDidChange), name: UIDevice.batteryLevelDidChangeNotification, object: nil)

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Battery level ranges from 0.0 (fully discharged) to 1.0 (100% charged). Before accessing this property, ensure that battery monitoring is enabled.

If battery monitoring is not enabled, battery state is UIDevice.BatteryState.unknown and the value of this property is –1.0.

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@objc func batteryLevelDidChange(_ notification: Notification) {
    print(batteryLevel)
}

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You can also verify the battery state:

var batteryState: UIDevice.BatteryState { UIDevice.current.batteryState }

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case .unknown   //  "The battery state for the device cannot be determined."
case .unplugged //  "The device is not plugged into power; the battery is discharging"
case .charging  //  "The device is plugged into power and the battery is less than 100% charged."
case .full      //   "The device is plugged into power and the battery is 100% charged."

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and add an observer for UIDevice.batteryStateDidChangeNotification:

NotificationCenter.default.addObserver(self, selector: #selector(batteryStateDidChange), name: UIDevice.batteryStateDidChangeNotification, object: nil)

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@objc func batteryStateDidChange(_ notification: Notification) {
    switch batteryState {
    case .unplugged, .unknown:
        print("not charging")
    case .charging, .full:
        print("charging or full")
    }
}

Check if battery charging status changes in real time Swift

Basically you did everything to display the current status, now you need to add something that is notified, or checks regularly for said status.
In this case, I believe the best way would be to register to the batteryStateDidChangeNotification notification, which is only sent by the system when isBatteryMonitoringEnabled is set to true, as you did in the viewDidLoad

I think adding

NotificationCenter.default.addObserver(
    self,
    selector: #selector(batteryStatus),
    name: UIDevice.batteryStateDidChangeNotification,
    object: nil
)

Should do the trick. In the viewDidLoad for instance.

Swift 3 Xcode: How to display battery levels as an integer?

Try this instead:

func someFunction() {
    self.infoLabel.text = String(format: "%.0f%%", batteryLevel * 100)
}

For future reference, all string format specifiers are listed here.

How to monitor battery level and state changes using swift

You can use the battery state notification UIDeviceBatteryStateDidChangeNotification and UIDeviceBatteryLevelDidChangeNotification to be notified when its state changed:

override func viewDidLoad() {
    super.viewDidLoad()
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "batteryStateDidChange:", name: UIDeviceBatteryStateDidChangeNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "batteryLevelDidChange:", name: UIDeviceBatteryLevelDidChangeNotification, object: nil)   

    // Stuff...
}

func batteryStateDidChange(notification: NSNotification){     
    // The stage did change: plugged, unplugged, full charge...
}

func batteryLevelDidChange(notification: NSNotification){     
   // The battery's level did change (98%, 99%, ...)
}

how to access device battery level from lock screen

I went through this this tutorial

and this seems to be working perfectly. I made only one change, that is, in info.plist file I added a new property Application does not run in background & gave it a value YES.

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