Reputation: 1633
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 <UIKit/UIKit.h>
@interface CalculatorAppDelegate : UIResponder <UIApplicationDelegate>
@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 <UIKit/UIKit.h>
@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
Upvotes: 135
Views: 195443
Reputation: 2111
Surprisingly, what worked for me was going to iOS Simulator menu, and pressing "Erase all Content and Settings...".
Go to Device
> Erase all Content and Settings...
Upvotes: 150
Reputation: 345
None of the suggested approaches resolved the issue I was facing, I was able to understand and resolve the issue on my own. I first put my doings and then explain my issue.
First I enabled my developer mode and dev security tools via the terminal:
defaults write com.apple.dt.Xcode DVTEnableCoreDevice enabled
sudo DevToolsSecurity -enable
Second I removed my simulator cache:
sudo rm -rf ~/Library/*/CoreSimulator
Third I force quit(kill) my simulator app service:
sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService
Fourth I attach the core simulator service from the Xcode top menu bar:
And finally, to make sure everything works fine I restart the system. And then I ran Xcode and was able to run the simulator without a problem.
So my issue was that the simulator app was not able to connect to the Xcode and it hung while trying.
Upvotes: 10
Reputation: 5055
What worked for me is remove the cache for Xcode and simulators. No need to uninstall them.
Goto ~/Library/Developer/Xcode
remove, caches, ios device logs etc (all the temporary things, it will be pretty clear there which things are just temporary).
Then goto ~/Library/Developer/CoreSimulator
and do the same with all the temporary files.
And note that, most probably, it is not an issue with your project but with the xcode and simulators.
Upvotes: 5
Reputation: 105
I've Xcode 13.2.1
What worked for me is on the Simulator Menu. Go to Device
and Erase All Content and Settings...
Upvotes: -1
Reputation: 95
Check right path for info.plist in Project - Build Sittings
Put info.plist into search field, and find line “info.plist File”
This in case of you move your info file into another folder.
Upvotes: -1
Reputation: 11
I was also getting the same problem but surprisingly what worked for me is
Upvotes: 0
Reputation: 381
For me, the simulator that was crashing was iPhone 13 with iOS 15.2. None of the solutions worked.
The CPU usage of the process 'syspolicyd' shot up whenever this issue occurred as well, but killing the process didn't help either.
Changing the device to a different one (File > Open Simulator > iOS 15.2 > iPhone 13 Pro Max) fixed the issue. After that, I started the previous device (iPhone 13) again, and it worked too.
Upvotes: 0
Reputation: 61
Faced this issue in Dec 2021 with iOS 13.7 simulator after Macbook Air went to sleep. The simulator screen was black with no signs of life. Resetting the simulator didn't help. Closing all windows and restarting the laptop didn't help. Ultimately it turned out that syspolicyd
was hogging 350% of the CPU. Killing this process solved the problem.
Upvotes: 0
Reputation: 5111
For me all it was needed was to shake the device (Device > Shake
). Weird but worked for me. If this doesn't work try resetting (Device > Erase All Content and Settings
) and then shake the device again.
Upvotes: 2
Reputation: 1547
I struggled with this for a couple of hours. Finally what solved it for me was:
sudo xcrun simctl erase all
xcrun simctl shutdown all
Upvotes: 13
Reputation: 886
I fixed this issue by cleaning the project by pressing
cmd + shift + k
and exited my simulator and built again.
Upvotes: 2
Reputation: 1450
I noticed I had accidentally deleted var window:UIWindow?
line from AppDelegate. Introducing it again fixed the issue for me!
Upvotes: 0
Reputation: 189
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: "Main", bundle: nil)
// workaround for svprogresshud
let appDelegate = UIApplication.shared.delegate as! AppDelegate
appDelegate.window = window
}
}
Upvotes: 2
Reputation: 118
This was my reason for having this issue.
For some reason, the "Is Initial View Controller" (for my main View Controller) was unchecked which was causing the black screen on load up.
Hope this helps someone out there!
Upvotes: 0
Reputation: 2315
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.
Upvotes: 0
Reputation: 2179
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)
Upvotes: 0
Reputation: 6156
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()
}
Upvotes: 17
Reputation: 876
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.
Upvotes: 0
Reputation: 121
Please check for all the constraints for all the views and review complete storyboard. Usually this happens because of that.
Regards, Arora
Upvotes: 0
Reputation: 885
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
Upvotes: 0
Reputation: 1927
I solved this only after removing simulators with prior iOS versions.
Upvotes: 0
Reputation: 345
Please make sure you have done this,if you are getting black screen after copying the storyboard from another project
Upvotes: 4
Reputation: 41
you could also go to Hardware -> reboot, then Hardware -> Home, and click on your App
Upvotes: 0
Reputation: 485
Just reset your simulator by clicking Simulator-> Reset Contents and Settings..
Upvotes: 0
Reputation: 11114
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;
}
Upvotes: 5
Reputation: 205
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.
Upvotes: 0
Reputation: 36447
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.
Upvotes: 7
Reputation: 69
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/
Upvotes: 4
Reputation: 91
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
Upvotes: 9