CODEWITHSUNDEEP
iphoneobjective-ciosuibutton
user1010563
user1010563

Reputation:

UIButton created programmatically but doesn't show up on view (addSubview was called)

Have an AppDelegate and a MainViewController. In MainViewController the UIButton was created, AppDelegate sets a background image and should show it on MainViewController. That's pretty much it but I can't see the UIButton.

Just for alignment purpose I created an IBOutlet and connected the button in IB.

MainViewController.h

@property (strong, nonatomic) IBOutlet UIButton *searchBtn;

MainViewController.m

@synthesize searchBtn;

AppDelegate.m

@synthesize mainVC;


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // ViewController > setup:
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.mainVC = [[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil];
    self.window.rootViewController = self.mainVC;
    self.window.backgroundColor = [UIColor whiteColor];

    // Buttons > Set background images:
    [self.mainVC.searchBtn setImage:[UIImage imageNamed:@"search.png"] forState:UIControlStateNormal];

    [self.mainVC.view addSubview:self.mainVC.searchBtn];

    [self.window makeKeyAndVisible];

    return YES;
}

Upvotes: 1

Views: 2128

Answers (2)

random
random

Reputation: 8608

You should be adding buttons in your MainViewController class, not the AppDelegate first off.

You should also set the background of the view in MainViewController, not the AppDelegate.

It should look like this:

AppDelegate.m

@synthesize mainVC;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // ViewController > setup:
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.mainVC = [[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil];
    self.window.rootViewController = self.mainVC;

    [self.window makeKeyAndVisible];

    return YES;
}

In your MainViewController.m's viewDidLoad put this

- (void)viewDidLoad {
    [super viewDidLoad];
    // Buttons > Set background images:
    [searchBtn setBackgroundImage:[UIImage imageNamed:@"search.png"] forState:UIControlStateNormal];

    //If you adding the button in Interface Builder you don't need to add it again
    //[self.view addSubview:self.mainVC.searchBtn];
}

Upvotes: 1

danqing
danqing

Reputation: 3668

First you don't need IBOutlet if you are creating it programmatically.

Second you probably want to move the creation of the button in viewDidLoad of your view controller rather than in your AppDelegate. It's your view controller's business.

Third you should probably alloc init your button if you create it programmatically:

UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(...)];
[button setBackgroundImage:someImage];
[button addTarget:self action:@selector(something:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:button];

something like that.

Upvotes: 6

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