I can't figure out why that code leads to app crash.
AppDelegate.h
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
self.rootViewController = [[[RootViewController alloc]init]autorelease];
[self.window setRootViewController:self.rootViewController];
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
Here is RootViewController.m code
-(void)loadView
{
UIView *view = [[UIView alloc]initWithFrame:CGRectMake(10, 10, 10, 10)];
[view setBackgroundColor:[UIColor lightGrayColor]];
[self.view addSubview:view];
[view release];
}
I get that message in the debugger
Unable to restore previously selected frame.
loadView is supposed to set the view. It is called when self.view is nil. Now you're calling [self.view addSubview:view]; UIKit calls loadView, and that creates an infinite recursion. You're supposed to do self.view = view; here.
loadView is responsible to set the view first. you missed to do that. Instead you added a view to self.view.
Change the code by below line:
self.view = view;
instead of [self.view addSubview:view];
Also it is advisable to call [super loadView] before returning from the function.
Related
I have a Navigation based Application named as diffView and in it I want to open new view on button click. For this a have created a view as file-new file-cocoa touch class-UIViewControllerSubclass named next1.
In diffViewAppDelegate.h I wrote as
IBOutlet UIButton *btn1;
#property (nonatomic,retain) UIButton *btn1;
-(IBAction)buttonPressed:(id)sender;
and in diffViewAppDelegate.m-
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
CGRect bounds=window.bounds;
UIView* view=[[UIView alloc]initWithFrame:bounds];
[view setBackgroundColor:[UIColor redColor]];
[window addSubview:view];
CGRect buttonFrame= CGRectMake(80, 240, 200, 30);
btn1=[[UIButton alloc] initWithFrame:buttonFrame];
[btn1 setTitle:#"space" forState:UIControlStateNormal];
[btn1.titleLabel setFont:[UIFont fontWithName:#"Verdana" size:20]];
[btn1 addTarget:self action:#selector(buttonPressed:) forControlEvents:UIControlEventTouchDown];
[view addSubview:btn1];
[self.window makeKeyAndVisible];
return YES;
}
-(IBAction)buttonPressed:(id)sender
{
next1 * nxt=[[next1 alloc] initWithNibName:nil bundle:nil];
[self.navigationController pushViewController:nxt animated:YES];
[nxt release];
}
I am not getting any error but when I click on the button nothing happens.
Please suggest me any solution.
Yes I have created the button in RootViewController but its not working.Even the button is not visible now. My code is like this-
CGRect buttonFrame= CGRectMake(80, 240, 200, 30);
btn1=[[UIButton alloc] initWithFrame:buttonFrame];
[btn1 setTitle:#"space" forState:UIControlStateNormal];
[btn1.titleLabel setFont:[UIFont fontWithName:#"Verdana" size:20]];
[btn1 addTarget:self action:#selector(buttonPressed:) forControlEvents:UIControlEventTouchDown];
[self.view addSubview:btn1];
How i imagine it:
In your delegate you load - alloc/init the UINaviagationController and set its rootViewController property or just using initWithRootViewController: method when you init the NavigationController. Something like that.
viewController = [RootViewController alloc] init];
nvc = [[UINavigationController alloc] initWithRootViewController:viewController];
nvc.navigationBarHidden = YES;
[self.window setRootViewController:nvc];
[window makeKeyAndVisible];
In your RootViewController, from 'viewDidLoad:' method you create the button and add it to 'self.view' after that you implement the target selector and everything will be fine.
EDIT 1:
That is my application:didFinishLaunchingWithOptions: method in my AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
// Override point for customization after application launch.
self.viewController = [[[ViewController alloc] init] autorelease];
self.navigationController = [[UINavigationController alloc] initWithRootViewController:self.viewController];
self.window.rootViewController = self.navigationController;
[self.window makeKeyAndVisible];
return YES;
}
That is my RootViewController
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
CGRect buttonFrame= CGRectMake(80, 240, 200, 30);
UIButton *btn1=[[UIButton alloc] initWithFrame:buttonFrame];
btn1.backgroundColor = [UIColor greenColor];
[btn1 setTitle:#"space" forState:UIControlStateNormal];
[btn1.titleLabel setFont:[UIFont fontWithName:#"Verdana" size:20]];
[btn1 addTarget:self action:#selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:btn1];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)buttonPressed:(id)sender
{
NSLog(#"sender: %#", sender);
}
#end
I want to know if it is possible to make multi view app without using the Interface Builder.
I know how to make it with just using Xcode and Storyboards, but I just want to be able make it programmatically.
For example : If I have a UIViewController A (default view) with a UIButton and than I have another UIViewController B with UIWebView so when I click on the UIButton of UIViewController A I want to be able to display the second View (Without IB).
How can I set the action to the UIButton to display my second View (Without Interface Builder) ?
You can add a target to your button:
[button addTarget:self action:#selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
Then in ControllerA, add this method:
-(void)buttonPressed:(id)sender
{
[self.superview addSubview:controllerB.view];
[self.view removeFromSuperview];
}
On ViewControllerA
- (void)viewDidLoad
{
UIButton *btn=[UIButton buttonWithType:UIButtonTypeRoundedRect];
[btn setFrame:CGRectMake(50.0f,200.0f,60.0f,30.0f)];
[btn setTitle:#"Next" forState:UIControlStateNormal];
[btn setTitleColor:[UIColor blackColor] forState:UIControlStateHighlighted];
[btn addTarget:self action:#selector(btnPressed:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:btn];
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
-(IBAction)btnPressed:(id)sender
{
NextViewController *nxt=[[NextViewController alloc]initWithNibName:nil bundle:nil];
[self.navigationController pushViewController:nxt animated:YES];
}
On viewControllerB
- (void)viewDidLoad
{
UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectMake(0,0, 320, 460)];
NSURL *targetURL = [NSURL URLWithString:#"http://developer.apple.com/iphone/library/documentation/UIKit/Reference/UIWebView_Class/UIWebView_Class.pdf"];
NSURLRequest *request = [NSURLRequest requestWithURL:targetURL];
[webView loadRequest:request];
[self.view addSubview:webView];
}
Make sure that in AppDelegate.h should be navigation controller like this
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.viewController = [[ViewController alloc] initWithNibName:#"ViewController" bundle:nil];
UINavigationController* navController = [[UINavigationController alloc] initWithRootViewController:self.self.viewController ];
self.window.rootViewController = navController;
[self.window makeKeyAndVisible];
return YES;
}
I have an iPad app I am making, but it crashes on startup even though there are no errors or warnings, the output doesn't output anything besides "(lldb)", and it marks a pointer.
This is the image of the post build crash.
And here is the code:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
/* UIImage *myImage = [UIImage imageNamed:#"de_dust2.png"];
myImageView = [[UIImageView alloc] initWithImage:myImage];
myScrollView.contentSize = CGSizeMake(myImageView.frame.size.width, myImageView.frame.size.height);
myScrollView.maximumZoomScale = 4.0;
myScrollView.minimumZoomScale = 0.75;
myScrollView.clipsToBounds = YES;
myScrollView.delegate = self;
// [myScrollView addSubview:myImageView];*/
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.viewController = [[ViewController alloc] initWithNibName:#"ViewController" bundle:nil];
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
[self.viewController setRed:1];
[self.viewController setGreen:0];
[self.viewController setBlue:0];
[self.viewController setAlpha:1];
[self.viewController checkRotation];
return YES;
}
I now also noticed that the error was given at the [self.window makeKeyAndVisible]; line.
Your code looks ok, the crash could be caused by some exception thrown parsing the XIB file of the window ...
Take a look at the Window in Interface Builder and try to temporary remove all reference to any IBOutlet present in the View Controller ...
I am using Xcode 4.5 and iOS 6.0, I have selected the default single view template from the xcode, I just want to add the label on the application window but I am unable to do so. Please correct me.
- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.viewController = [[ViewController alloc] initWithNibName:#"ViewController" bundle:nil];
self.window.rootViewController = self.viewController;
label =[[UILabel alloc] initWithFrame:CGRectMake(100, 100, 200, 20)];
label.text = #"Test";
[label setBackgroundColor:[UIColor whiteColor]];
[self.window addSubview:label];
[self.window bringSubviewToFront:label];
[self.window makeKeyAndVisible];
return YES;
}
PS - I want my label on top of my ViewController view i.e. on the window so it will be always there despite changes in the views presented by window. I dont want to only show the label here.
I got the answer
[self.window.rootViewController.view addSubview:label];
Thanks all for giving the pointers.
Just Remove the RootviewController.
- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
label =[[UILabel alloc] initWithFrame:CGRectMake(100, 100, 200, 20)];
label.text = #"Test";
[label setBackgroundColor:[UIColor whiteColor]];
[self.window addSubview:label];
[self.window bringSubviewToFront:label];
[self.window makeKeyAndVisible];
return YES;
}
if you dont want to only show the label here then use like below.
self.viewController = [[ViewController alloc] initWithNibName:#"ViewController" bundle:nil];
self.window.rootViewController = self.viewController;
[self.Viewcontroller.view addSubview:label];
Add the label to self.window.rootViewController.view instead of self.window
UILabel *label =[[UILabel alloc] initWithFrame:CGRectMake(100, 100, 200, 20)];
label.text = #"Test"; [label setBackgroundColor:[UIColor whiteColor]];
[self.window.rootViewController.view addSubview:label];
I am trying to actually test out how to hard code interfaces just using the single view template Xcode provides for now.
I have given AppDelegate.h an ivar and property of UILabel *titleLabel; and my AppDelegate.m code is declared in the -(void) did finish launching:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
// Set the view controller as the window's root view controller and display.
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
return YES;
UIButton *button = [UIButton buttonWithType: UIButtonTypeRoundedRect];
button.titleLabel.font = [UIFont systemFontOfSize: 12];
button.titleLabel.lineBreakMode = UILineBreakModeTailTruncation;
button.titleLabel.shadowOffset = CGSizeMake (1.0, 0.0);
[self.window addSubview: button];
}
I get a successful compile, but the button is not drawn on the screen--I just get the standard blank template running in the simulator. How do I get it to draw?
Your window appears to be uninitialized, and your function is returning too early. Try this:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
self.window = [[UIWindow alloc]initWithFrame:[[UIScreen mainScreen]bounds]];
// Set the view controller as the window's root view controller and display.
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
UIButton *button = [UIButton buttonWithType: UIButtonTypeRoundedRect];
button.titleLabel.font = [UIFont systemFontOfSize: 12];
button.titleLabel.lineBreakMode = UILineBreakModeTailTruncation;
button.titleLabel.shadowOffset = CGSizeMake (1.0, 0.0);
[self.window addSubview: button];
return YES;
}
Remember that return immediately exits a function, and any code below it will not be executed.