问题
How can I check if the screen is on or off in iOS? I'd like to know if the screen is currently on, even my app is in the background. I'd like to have an event listener on this. thanks.
回答1:
In Swift 3 you can do:
override func viewDidLoad() {
super.viewDidLoad()
// Observer UIApplicationDidBecomeActive,UIApplicationDidEnterBackground
NotificationCenter.default.addObserver(
self,
selector: #selector(MyViewController.applicationDidBecomeActive(notification:)),
name: NSNotification.Name.UIApplicationDidBecomeActive,
object: nil)
NotificationCenter.default.addObserver(
self,
selector: #selector(MyViewController.applicationDidEnterBackground(notification:)),
name:NSNotification.Name.UIApplicationDidEnterBackground,
object: nil)
}
func applicationDidBecomeActive(notification: NSNotification) {
// here my app did become active
}
func applicationDidEnterBackground(notification: NSNotification) {
// here my app did enter background
}
You can find more details in the official guide.
Details from the actual sources:
extension NSNotification.Name {
// These notifications are sent out after the equivalent delegate message is called
@available(iOS 4.0, *)
public static let UIApplicationDidEnterBackground: NSNotification.Name
@available(iOS 4.0, *)
public static let UIApplicationWillEnterForeground: NSNotification.Name
public static let UIApplicationDidFinishLaunching: NSNotification.Name
public static let UIApplicationDidBecomeActive: NSNotification.Name
public static let UIApplicationWillResignActive: NSNotification.Name
public static let UIApplicationDidReceiveMemoryWarning: NSNotification.Name
public static let UIApplicationWillTerminate: NSNotification.Name
public static let UIApplicationSignificantTimeChange: NSNotification.Name
public static let UIApplicationWillChangeStatusBarOrientation: NSNotification.Name // userInfo contains NSNumber with new orientation
public static let UIApplicationDidChangeStatusBarOrientation: NSNotification.Name // userInfo contains NSNumber with old orientation
// userInfo dictionary key for status bar orientation
public static let UIApplicationWillChangeStatusBarFrame: NSNotification.Name // userInfo contains NSValue with new frame
public static let UIApplicationDidChangeStatusBarFrame: NSNotification.Name // userInfo contains NSValue with old frame
// userInfo dictionary key for status bar frame
@available(iOS 7.0, *)
public static let UIApplicationBackgroundRefreshStatusDidChange: NSNotification.Name
@available(iOS 4.0, *)
public static let UIApplicationProtectedDataWillBecomeUnavailable: NSNotification.Name
@available(iOS 4.0, *)
public static let UIApplicationProtectedDataDidBecomeAvailable: NSNotification.Name
// Key in options dict passed to application:[will | did]FinishLaunchingWithOptions and info for UIApplicationDidFinishLaunchingNotification
// This notification is posted after the user takes a screenshot (for example by pressing both the home and lock screen buttons)
@available(iOS 7.0, *)
public static let UIApplicationUserDidTakeScreenshot: NSNotification.Name
}
回答2:
You can try this code for getting state of screen in ios.
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), //center
NULL, // observer
displayStatusChanged, // callback
CFSTR("com.apple.iokit.hid.displayStatus"), // event name
NULL, // object
CFNotificationSuspensionBehaviorDeliverImmediately);
回答3:
In swift 5 only this worked for me:
https://stackoverflow.com/a/55711257/7505029
来源:https://stackoverflow.com/questions/40171495/ios-can-i-detect-if-the-device-screen-is-on-off