Launch iOS simulator from Xcode and getting a black screen followed by Xcode hanging and unable to stop tasks

Question

I m having trouble running my basic iPhone application  while going through the Stanford iTunes CS193p lectures  in the iOS simulator   I ve been searching for a while  both Google and SO   but unable to find a solution so far  There are many similar bugs  but the solutions don t seem to fix this   In Xcode I click  run   It compiles and builds successfully  launches iOS simulator but it never gets to loading the app  Only the status bar at the top   With a black screen   I ve only written very basic code  following along with the lectures  and can t get past this problem     To confuse matters more  I wrote a web wrapper  UIWebView  before these lectures and this works fine  But there is barely any difference in the code   All new apps I create from scratch all fail with the same black screen problem    If I hit the home button on the simulator and launch the app  it will display  But Xcode doesn t seem to know what s going on   It s as if Xcode has lost the ability to talk to iOS Simulator and assumes it s running  even if I quit iOS simulator   I try and quit Xcode  and it asks me to stop the tasks  Then it just hangs   So I have to force restart to get out of Xcode   I m using   OSX 10 8 2 Xcode 4 5 2 iOS Simulator 6 0  CalculatorAppDelegate h   import  lt UIKit UIKit h gt    interface CalculatorAppDelegate   UIResponder  lt UIApplicationDelegate gt    property  strong  nonatomic  UIWindow  window    end   CalculatorAppDelegate m   import  CalculatorAppDelegate h    implementation CalculatorAppDelegate  -  BOOL application  UIApplication   application didFinishLaunchingWithOptions  NSDictionary   launchOptions          Override point for customization after application launch      return YES     -  void applicationWillResignActive  UIApplication   application      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 throttle down OpenGL ES frame rates  Games should use this method to pause the game     -  void applicationDidEnterBackground  UIApplication   application      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     -  void applicationWillEnterForeground  UIApplication   application      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     -  void applicationDidBecomeActive  UIApplication   application      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     -  void applicationWillTerminate  UIApplication   application      Called when the application is about to terminate  Save data if appropriate  See also applicationDidEnterBackground       end   CalculatorViewController h   import  lt UIKit UIKit h gt    interface CalculatorViewController   UIViewController  property  weak  nonatomic  IBOutlet UILabel  display    end   CalculatorViewController m   import  CalculatorViewController h    implementation CalculatorViewController   synthesize display    display   -  IBAction digitPressed  UIButton   sender       NSString  digit    sender currentTitle   NSLog   digit pressed        digit       end

User · Answer

I had the same issue with Xcode    black screen on launching apps  no debugging and clicking would lock up Xcode    I finally found the problem    following the lead that the simulator could not connect to Xcode I took a look at my etc hosts file and found that months ago to solve a different issue I had edited the host file to map localhost to my fixed IP instead of the default    my value   10 0 1 17 localhost  This should work since that is my IP  but changing it back to the default IP fixed Xcode     127 0 0 1  localhost   Hope this helps

User · Answer

Another Solution is that if you are building UI programatically in  Objective C project  then you might need to add some code to inflate the view  so you will need to add those 3 lines to make the window s interface interacts with the code  the outer 2 are actually interacting with the code and the other one will change the screen to white so you will know it works    -  BOOL application  UIApplication   application didFinishLaunchingWithOptions  NSDictionary   launchOptions    self window     UIWindow alloc  initWithFrame    UIScreen mainScreen  bounds       Override point for customization after application launch        self window backgroundColor    UIColor whiteColor    self window makeKeyAndVisible     return YES

User · Answer

you could also go to Hardware -  reboot  then Hardware -  Home  and click on your App

User · Answer

In case you recently updated to Xcode 11 beta 3 and try to run an older SwiftUI project  you have to make some changes in the SceneDelegate where the views are loaded  otherwise the screens will remain black on devices running iOS 13 beta 3 which of course includes all simulators        func scene   scene  UIScene  willConnectTo session  UISceneSession  options connectionOptions  UIScene ConnectionOptions           Use this method to optionally configure and attach the UIWindow  window  to the provided UIWindowScene  scene          If using a storyboard  the  window  property will automatically be initialized and attached to the scene         This delegate does not imply the connecting scene or session are new  see  application configurationForConnectingSceneSession  instead           Use a UIHostingController as window root view controller     if let windowScene   scene as  UIWindowScene           let window   UIWindow windowScene  windowScene          window rootViewController   UIHostingController rootView  ContentView            self window   window         window makeKeyAndVisible             The behavior not strictly limited to the simulators  but since most people will run beta software exclusively on simulators it will only occur in this context  It baffled me for quite a while  so hope it helps

User · Answer

Please check for all the constraints for all the views and review complete storyboard  Usually this happens because of that   Regards  Arora

User · Answer

Please make sure you have done this if you are getting black screen after copying the storyboard from another project

User · Answer

To make sure it s a simulator issue  see if you can connect to the simulator with a brand new project without changing any code   Try the tab bar template   If you think it s a simulator issue  press the iOS Simulator menu   Select  Reset Content and Settings       Press  Reset    I can t see your XIB and what  properties you have connected in Interface Builder  but it could also be that you re not loading your window  or that your window is not loading your view controller

User · Answer

I was developing flutter using android studio and running the simulator  the simulator was dark and I reset the contents as per accepted answer  But that didn t fix my issue  My CPU was running somehow high enough  so I restarted   but not fixed the issue  I opened Xcode and run one of my native iOS apps  the simulator re-opened as usual  I closed the Xcode and opened Android Studio  then started developing flutter app again

User · Answer

Be sure that Initial View Controller is set

User · Answer

I am a newbie to the iOS app development  I was practising to develop iOS apps from the very beginning and while running a very basic Hello World app  I also faced same issue that only a black blank screen appears after building and running the app in iOS simulator  Somehow while struggling to find out a solution to the problem I accidentally clicked Window-- Scale-- 50  in iOS simulator and it did solve my problem  I could then see the Home page with my app and clicking on app icon I was able to run my app successfully  App versions  Xcode 5 1 iOS Simulator  7 1 OSX  10 9 3

User · Answer

I solved this only after removing simulators with prior iOS versions

User · Answer

I had black simulator screens only for iOS 11 sims  After trying to reset  reboot  reinstall and creating a brand new useraccount on my machine I found this solution   defaults write com apple CoreSimulator IndigoFramebufferServices FramebufferRendererHint 3   found in this answer here  Xcode 9 iOS Simulator becoming black screen after installing Xcode 10 beta

User · Answer

I noticed I had accidentally deleted var window UIWindow  line from AppDelegate  Introducing it again fixed the issue for me

User · Answer

I ve managed to find the fix for this  It was found courtesy of this blog post    http   vandadnp wordpress com 2012 03 18 xcode-4-3-1-cannot-attach-to-ios-simulator   The solution is to press cmd shift    command  shift and then comma        that loads some options for release or debugging    Change the debugger from LLDB to GDB  This fixes the issue

User · Answer

Surprisingly  what worked for me was going to iOS Simulator menu  and pressing  Reset Content and Settings    in iOS 13  its under Hardware

User · Answer

What happened with me was the Type of class was not UIViewController for the script attached to my view controller  It was for a UITabController      I had mistakenly quickly created the wrong type of class     So make sure the class if the correct type   Hope this helps someone  I was in a rush and made this mistake

User · Answer

This could result from not setting the correct deployment info   i e  if your storyboard isn t set as the main interface

User · Answer

If you re using SwiftUI  If you re updating from a previous version of Xcode 11  there are some changes to the SceneDelegate willConnectTo session  options connectionOptions initialization    The main window is now initialized using UIWindow windowScene  windowScene   where it use to be UIWindow frame  UIScreen main bounds   On previous version       let window   UIWindow frame  UIScreen main bounds      window rootViewController   UIHostingController rootView  ContentView        self window   window     window makeKeyAndVisible     In new version       if let windowScene   scene as  UIWindowScene           let window   UIWindow windowScene  windowScene          window rootViewController   UIHostingController rootView  ContentView            self window   window         window makeKeyAndVisible

User · Answer

I solved this question with set window background color like this in iOS 13  func scene   scene  UIScene  willConnectTo session  UISceneSession  options connectionOptions  UIScene ConnectionOptions        guard let      scene as  UIWindowScene  else   return       if let windowScene   scene as  UIWindowScene           window   UIWindow windowScene  windowScene          window  backgroundColor    white         let storyBoard   UIStoryboard name   quot Main quot   bundle  nil                      workaround for svprogresshud         let appDelegate   UIApplication shared delegate as  AppDelegate         appDelegate window   window

User · Answer

Just reset your simulator by clicking Simulator-  Reset Contents and Settings

User · Answer

Solution 1   You can Quit simulator and try again   Solution 2  Recommended    Go to iOS Simulator -  Reset Content and Settings       This will pop-up an alert stating  Are you sure you want to reset the iOS Simulator content and settings      Select Reset if you wish to or else Don t Reset button   Note that once you reset simulator content all app installed on simulator will be deleted and it will reset to initial settings

User · Answer

Before resetting the emulator first go to your projects  project navigator  screen and under the general -  depoyment info screen check that the main interface  property is properly setup

User · Answer

When i have carried my project on Xcode 11 1  i got that problem  That black screen problem may occur any presentation inter ViewControllers   That answer helped me  Because modal presentation changed with iOS 13   If you don t get that problem before iOS 13  please try to add line below to your ViewController before its presentation   viewController modalPresentationStyle    fullScreen   after your code may seem like below   let vc   UIViewController   vc modalPresentationStyle    fullScreen   or  overFullScreen for transparency self present vc  animated  true  completion  nil

User · Answer

This was my reason for having this issue  For some reason  the  quot Is Initial View Controller quot   for my main View Controller  was unchecked which was causing the black screen on load up  Hope this helps someone out there

User · Answer

Restarting your computer should be all you need to do

User · Answer

I was doing what doug suggests   Reset Content and Settings   which works but takes a lot of time and it is really annoying    until I recently found completely accidental another solution that is much quicker and seems to also work so far  Just hit cmd L on your simulator or go to the simulator menu  Hardware -  Lock   which locks the screen  when you unlock the screen the app works like nothing ever happened

User · Answer

If you should loose your entry point in your Storyboard or simply wish to change the entry point you can specify this in Interface Builder  To set a new entry point you must first decide which ViewController will act as the new entry point and in the Attribute Inspector select the Initial Scene checkbox   You can try  http   www scott-sherwood com ios-5-specifying-the-entry-point-of-your-storyboard

[ios] Launch iOS simulator from Xcode and getting a black screen, followed by Xcode hanging and unable to stop tasks

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