RemoveFromSuperView not working on UIButton - ios

Question

It seems like such a simple thing to remove a button from a view, but it is not working.
MyViewController.h
#import <UIKit/UIKit.h>
#interface MyViewController : UIViewController
#property (strong, nonatomic, readonly, getter = getMyButton) UIButton* myButton;
- (id) init;
- (id) getMyButton;
#end
MyViewController.m
#import "MyViewController.h"
#interface MyViewController ()
#end
#implementation MyViewController
#synthesize myButton = _myButton;
- (id) init
{
if([super initWithNibName: nil bundle: nil])
{
_myButton = nil;
}
return self;
}
- (id) getMyButton
{
if(!_myButton) _myButton = [self createMyButton];
return _myButton;
}
- (void) viewDidLoad
{
[super viewDidLoad];
UIButton* myButton = self.myButton;
[self.view addSubview: myButton];
}
- (void) didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
- (UIButton*) createMyButton
{
UIButton *button = [[UIButton alloc] init];
[button setTitle: #"My Button"
forState: UIControlStateNormal];
[button addTarget: self
action: #selector(myAction:)
forControlEvents: UIControlEventTouchUpInside];
button.frame = CGRectMake(10, 10, 100, 40);
return button;
}
- (void) myAction: (id) sender
{
[self.myButton performSelectorOnMainThread: #selector(removeFromSuperview) withObject: nil waitUntilDone: NO];
}
#end
But no luck. Clicking the button simply does nothing.
If it is not a problem of concurrency then maybe it is a memory management problem? Maybe it is just something daft, I don't know.
I tried putting the following line into the myAction method
NSLog(#"Test 1");
if(_startButton.superview) NSLog(#"Test 2");
Only 'Test 1' is logged. Perhaps that is a clue but what I don't know is why the button has no superview when it is added to view and is visible on the screen
Additional information
I don't know, if any of this is relevant, but maybe
I just updated Xcode to the latest version from the developer program (it supported up to iOS version 7.0 before, now 7.1)
I just started testing the app on an actual iPhone (I get the same problem testing with the simulator though)
Around the same time as this problem I also noticed that NSLog function doesn't work inside AppDelegate applicationHasLaunched method
Thanks

Answer 1

You didn't set the action for that button.
Change your createMyButton method like:
- (UIButton*) createMyButton
{
UIButton *button = [[UIButton alloc] init];
[button setTitle: #"My Button"
forState: UIControlStateNormal];
button.frame = CGRectMake(10, 10, 100, 40);
[button addTarget:self action:#selector(myAction:) forControlEvents:UIControlEventTouchUpInside];
return button;
}
Also change myAction method like:
- (void)myAction:(UIButton *)sender
{
[sender performSelectorOnMainThread: #selector(removeFromSuperview) withObject: nil waitUntilDone: NO];
}

Answer 2

Your code seems overly complicated:
Why do you need to lazy create the button?
Why does it need to be readonly?
Why do you need the performselector in your action?
I have taken the liberty to rewrite your code:
Header file
#property (nonatomic,strong) UIButton * button;
Code file
- (void)viewDidLoad
{
[super viewDidLoad];
self.button = [UIButton buttonWithType:UIButtonTypeSystem];
[self.button setTitle:#"MyButton" forState:UIControlStateNormal];
self.button.frame = self.view.bounds;
[self.button addTarget:self action:#selector(myAction:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.button];
}
-(void)myAction:(UIButton*)sender
{
[sender removeFromSuperview];
}
Happy coding!
Edit
If you insist on going with your original code, try changing
- (id) getMyButton
to
-(UIButton*)myButton

Answer 3

Buttons are a class family and should be created with [UIButton buttonWithType:]

Answer 4

I am sure that your myAction is not get fired. Cause you forget to addTarget
on your createMyButton method just add one more line
[button addTarget:self action:#selector(myAction:) forControlEvents:UIControlEventTouchUpInside];

Answer 5

UPDATE: You've also marked this question as iOS but you are importing OSX headers
#import "NSViewController.h"
#interface MyViewController: NSViewController
you should be inheriting from UIViewController
#import <UIKit/UIKit.h>
#interface MyViewController : UIViewController
Are you creating the view controller via the init code you've posted?
- (id) init
{
if([super initWithNibName: nil bundle: nil])
{
_myButton = nil;
}
return self;
}
Here you are not allocating anything to self the code should be
- (id) init
{
self = [super initWithNibName: nil bundle: nil];
if(self)
{
_myButton = nil;
}
return self;
}