Skip to main content

Semaphore | Delay splash screen in iOS + Objective C

  • How to wait for an asynchronously dispatched block to finish?
  • How to integrate semaphore in iOS?
  • How to delay splash screen for longer time, so that developer can prefetch or execute something before start of iOS App.

The answer of all the above questions is SEMAPHORE.  A semaphore is a variable or abstract data type used to control access to a common resource by multiple processes in a concurrent system such as a multiprogramming operating system. 

Suppose you want to perform some task before root view controller is shown to user. 
Goto AppDelegate's method didFinishLaunchingWithOptions, create a method as below:- 

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [self performTaskToDelaySplash];
}


-(void) performTaskToDelaySplash {
    
    dispatch_semaphore_t semaphore = dispatch_semaphore_create(0); //1. Create semaphore
    
//Perform your task here, i.e Any webservice call or any database operation

         dispatch_semaphore_signal(semaphore); //3, write this line when your task completes

    while (dispatch_semaphore_wait(semaphore, DISPATCH_TIME_NOW)) { //2
        [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate dateWithTimeIntervalSinceNow:100]];
    }
}


Stackover flow reference post.

Comments

  1. i love this put up. I understand that my intention readers are my students within the beyond. best essay writing service I’d want to mark like this too appealing occasion and actual hard art work to make a super article. thank you for the guidelines, I in reality loved analyzing this. it's so lots inspiring.

    ReplyDelete

Post a Comment

Popular posts from this blog

Play youtube video in iOS app

Youtube video can be played in iOS app using webview. MPMoviePlayerController is not able to open youtube video automatically. Integrate the below script to show thumbnail, clicking on it the video will play in full screen.


NSString *url = @"https://www.youtube.com/embed/8aMHGC6A5zc"; NSString* embedHTML = @"\     <html><head>\     <style type=\"text/css\">\     body {\     background-color: transparent;\     color: white;\     }\     </style>\     </head><body style=\"margin:0\">\     <iframe id=\"yt\" src=\"%@\" type=\"application/x-shockwave-flash\" \     width=\"%0.0f\" height=\"%0.0f\" frameborder=\"0\" feature=player_detailpage allowfullscreen></iframe>\     </body></html>"; NSString* html = [NSStringstringWithFormat:embedHTML, url, self.view.frame.size.width, 200.0];
    [webviewloadHTMLString:html baseURL:nil];


///*******************A…

Disabling print for Production In Swift Project

You'll need to set up a compiler flag to use the Swift preprocessor - go to the Swift Compiler - Custom Flags section of Build Settings to set up a -D DEBUG flag:



Then in your code you can define a DLog() function and only print your message if the DEBUG flag is set:
func DLog(message: String, function: String = __FUNCTION__) { #if DEBUG     println("\(function): \(message)") #endif }

Return multiple values from a function in objective C

We can return tuples in swift as follows:-

func getData()->(Int,Int,Int){//...code herereturn( hour, minute, second)}You can't do that in objective-c. Best option is using parameters by reference. Something like this.