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What does it mean to put something in my application didFinishLaunchingWithOptions method:. And how do i do it in swift?
There is a boiler plate method provided in your iOS project's AppDelegate file defined as
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch. Here you can out the code you want.
return true
}
If you want to handle cases such as if app is opened by a URL or by remote notification then you might want to put your code before return.
If the app can handle the url then keep the return value true otherwise false. In case of push notification, the return value would anyway be ignored.
Hope this would help.
This function gets invoked right before your app is fully loaded. If you're familiar with jQuery, it's sort of like $(document).ready(function() {}) Below is a link to documentation from Apple on how to implement this function:
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIApplicationDelegate_Protocol/index.html?hl=ar#//apple_ref/occ/intfm/UIApplicationDelegate/application:didFinishLaunchingWithOptions:
application:didFinishLaunchingWithOptions: is part of the UIApplicationDelegate protocol, which is responsible with handling different changes over your application state. You can find out more about this method and about the app delegate protocol in the Apple documentation from here. I strongly recommend reading it before moving forward.
You should get the below code automatically generated by Xcode if you create a brand new Swift iOS project:
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
// ...
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.
return true
}
You can place the code you need into that method, or add the method to your UIApplicationDelegate if it's not already there.
Related
iOS Extension - Fatal Exception: com.firebase.core Default app has already been configured.
enter image description here
From the message it is clear that FIRApp's configure function is called twice by your app. It is supposed to call once. The best place to call it, is in the func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool in your AppDelegate.
In order to identify from where it is being called you can use 2 approaches.
Press CMD + Shift + F and search for configure keyword and identify from the results.
Add a symbolic break point and app will pause when configure function get called. See the screenshots below:
I have this code that show a message "Msg Background" when the application is in Background. What I need is that as long as the application continues in the background show that message every 2 minutes (just an example of time). So far the code I have shows the message only once, apparently this sentence is not working properly.
UIApplication.shared.setMinimumBackgroundFetchInterval (UIApplication.backgroundFetchIntervalMinimum)
I also have this warning: 'setMinimumBackgroundFetchInterval' was deprecated in iOS 13.0: Use a BGAppRefreshTask in the BackgroundTasks framework instead
I am using swift 5 and Xcode 11
class AppDelegate: UIResponder, UIApplicationDelegate {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
GMSServices.provideAPIKey("AIzaSyBSpAt5zqvbh73FmG_Kb6xpiFMkWRmHppg")
UIApplication.shared.setMinimumBackgroundFetchInterval(UIApplication.backgroundFetchIntervalMinimum)
return true
}
func application(_ application: UIApplication, performFetchWithCompletionHandler completionHandler: #escaping (UIBackgroundFetchResult) -> Void) {
print("Msg Background")
}
}
As Paulw11 said, it's not called in fixed interval. The OS controls when it is going to be executed. We cannot expect the specific time because of it.
You probably know this, but I'm going to add this bit just in case, setMinimumBackgroundFetchInterval has deprecated on iOS 13 and later. You might want to consider to use BackgroundTasks Framework instead.
but if you want to test performFetchWithCompletionHandler, you can use XCode Navigation Bar > Debug > perform Background Fetch.
screenshot of XCode navigation bar to find option
I hope it can help!
I want to call an action which will get called every time any app start.
Example:
Showing a modal with app name saying Welcome to Twitter.
you can add that action in this method of app delegate
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
perfornAction()
return true
}
There are 2 methods in which you can write your code.
applicationWillEnterForeground: Gets called when you app comes into picture after INACTIVE or TERMINATED state
didFinishLaunchingWithOptions: Gets called when app gets called for first time. Also this method will get called when app is in terminated state and you open the app.
So if you want to perform it every time when app opens, prefer applicationWillEnterForeground. And for first time user call same method in didFinishLaunchingWithOptions with some flag value(Set it to true when your code runs successfully) so that your method will not get called twice.
I had updated my Xcode 7.3 to Xcode 8.
It is showing multiple warnings in AppDelegate. The warning is as follows.
Extraneous '_' in parameter: 'application' has no keyword argument name
My AppDelagate.swift file is this:
import UIKit
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
return true
}
func applicationWillResignActive(_ application: UIApplication) {
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
}
func applicationDidEnterBackground(_ application: UIApplication) {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}
func applicationWillEnterForeground(_ application: UIApplication) {
// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
}
func applicationDidBecomeActive(_ application: UIApplication) {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}
func applicationWillTerminate(_ application: UIApplication) {
// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}
}
when I followed the Xcode suggestion to remove _ in the functions that shows warning.
I got rid of the above warning. But now I get a new warning for
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
return true
}
The warning is:
Non-#objc method 'application(_:didFinishLaunchingWithOptions:)' cannot satisfy optional requirement of #objc protocol 'UIApplicationDelegate'
I followed the solutions online. But had no luck in getting rid of this warning.
Any help would be appreciated.
Thanks.
Your code is correct for Swift 3. But the environment you are in clearly thinks it is supposed to be Swift 2, and that is the reason for the error messages.
It sounds as if you have accidentally opened the file in Xcode 7. That would explain it. Your code is now Swift 3. Xcode 7 is Swift 2; it does not know about Swift 3 and doesn't understand your code.
Now that you have converted to Swift 3, you can never use Xcode 7 with this project ever again.
Or maybe this is Xcode 8 but the legacy build setting is still on, so it thinks this is supposed to be Swift 2. But it isn't. It is Swift 3.
I am learning iOS development and the following code is from the book Programming iOS8 by Matt Neuberg. It is an app delegate class to create a window. I do not understand -
In the second line what is #UIApplicationMain and why is it there? Is it a declaration of a global varibale?
What is the purpose of the parameter didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?? I don't see it used anywhere in the function body.
import UIKIT
#UIApplicationMain
class AppDelegate : UIResponder, UIApplicationDelegate {
var window : UIWindow?
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
self.window = UIWindow(frame:UIScreen.mainScreen().bounds)
self.window!.backgroundColor = UIColor.whiteColor()
self.window!.makeKeyAndVisible()
return true
}
}
The #UIApplicationMain attribute in Swift replaces the trivial
main.m file found in Objective-C projects (whose purpose is to
implement the main function that's the entry point for all C programs
and call UIApplicationMain to kick off the Cocoa Touch run loop and
app infrastructure).
In Objective-C, the main (heh) bit of per-app configuration that the
UIApplicationMain function provides is designating one of your app's
custom classes as the delegate of the shared UIApplication object.
In Swift, you can easily designate this class by adding the
#UIApplicationMain attribute to that class' declaration. (You can
also still invoke the UIApplicationMain function directly if you
have reason to. In Swift you put that call in top-level code in a
main.swift file.)
#UIApplicationMain is for iOS only. In OS X, the app delegate is
traditionally set in the main nib file designated by the Info.plist
(the same for Swift as for ObjC) — but with OS X storyboards there's
no main nib file, so #NSApplicationMain does the same thing there.
Reference from HERE.
And for your second point didFinishLaunchingWithOptions:
Every app begins with UIApplicationDelegate -application:didFinishLaunchingWithOptions: (or more accurately, -application:willFinishLaunchingWithOptions:, when implemented). It is called by the application to notify its delegate that the launch process is finishing, and nearly ready to run.