更改未在Interface Builder中创建的UIButton的文本

Question

This question seems to have been answered a lot but none of the posted solutions work for me. So I thought I would give this a shot. I have a boolean posNeg and every time its value changes, the title of three buttons should change but they don't.

- (void) posNegButtonPressed{
    if (posNeg) {
        posNeg = NO;
        [oneButton setTitle:@"One" forState:UIControlStateNormal];
        [xButton setTitle:@"X" forState:UIControlStateNormal];
        [x2Button setTitle:@"X2" forState:UIControlStateNormal];
        NSLog(@"Was True");
    }
    else{
        posNeg = YES;
        [oneButton setTitle:@"-One" forState:UIControlStateNormal];
        [xButton setTitle:@"-X" forState:UIControlStateNormal];
        [x2Button setTitle:@"-X2" forState:UIControlStateNormal];
        NSLog(@"Was False");
    }
}

The NSLog's are being called, so I keep getting an alternating sequence of "Was True" and "Was False" but the title of each of the buttons is never updated.

Additional Info:

Buttons were initialized as follows

Header File

@interface ...{ 
    UIButton* oneButton;
    UIButton* xButton;
    UIButton* x2Button; 
} 
@end

Implementation File

@implementation ...

- (id)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        [self setUpButton : oneButton : UIButtonTypeRoundedRect : @"One" :UIControlStateNormal : @"Helvetica-Bold" : 20
                      : width - width/4 + 2 * initialWidth : height/3 + 6 * (buttonHeight + spaceBetweenButtons)
                      : width/4 - 2 * initialWidth : buttonHeight : @selector(oneButtonPressed) : UIControlEventTouchUpInside];

        [self setUpButton : xButton : UIButtonTypeRoundedRect : @"X" :UIControlStateNormal : @"Helvetica-Bold" : 20
                      : width - width/4 + 2 * initialWidth : height/3 + 7 * (buttonHeight + spaceBetweenButtons)
                      : width/4 - 2 * initialWidth : buttonHeight : @selector(xButtonPressed) : UIControlEventTouchUpInside];

        [self setUpButton : x2Button : UIButtonTypeRoundedRect : @"X\u00B2" :UIControlStateNormal : @"Helvetica-Bold" : 20
                      : width - width/4 + 2 * initialWidth : height/3 + 8 * (buttonHeight + spaceBetweenButtons)
                      : width/4 - 2 * initialWidth : buttonHeight : @selector(x2ButtonPressed) : UIControlEventTouchUpInside];
}

- (void) setUpButton: (UIButton *) button : (UIButtonType *) buttonType : (NSString *) title : (UIControlState *) controlState : (NSString *) font : (int) size : (double) xPos (double) yPos : (double) width : (double) height : (SEL) selectorMethod :(UIControlEvents *) controlEvent
{
    button = [UIButton buttonWithType:buttonType];
    button.frame = CGRectMake(xPos, yPos, width, height);
    [button setTitle:title controlState  ];
    [button addTarget:self action: selectorMethod forControlEvents:controlEvent];
    [self addSubview:button];
    button.titleLabel.font = [UIFont fontWithName:font size:size];
}

@end

I tried [mybutton setNeedsDisplay] but that didn't work either

Any ideas? Are my buttons not initialized properly?

Edit 1: Added NSLog(@"%@ %@ %@", oneButton, xButton, x2Button); to the last line in initWithFrame as requested and got (null) (null) (null). Does anyone know why this they're null?

Answer 1

Please set IBOutlet for button if you are using XIB,below code is working for me

- (IBAction)sliderButtonAction:(UIButton *)sender {

    [self.suggestedTableView reloadData];
    if ([sender.titleLabel.text isEqualToString:@"<<"]) {
        [sender setTitle:@">>" forState:UIControlStateNormal];
    }
    else {
        [sender setTitle: @"<<" forState: UIControlStateNormal];

    }
}

Answer 2

If it is create by XIB then you need to set IBOutlet for each button. And i think you have done silly mistake. So please check your IBOutlet is connected or not. Because in this code there is no mistake.

Answer 3

This is problem of pass by value and pointer.

When you call this:

[self setUpButton : oneButton : UIButtonTypeRoundedRect : @"One" :UIControlStateNormal : @"Helvetica-Bold" : 20
                      : width - width/4 + 2 * initialWidth : height/3 + 6 * (buttonHeight + spaceBetweenButtons)
                      : width/4 - 2 * initialWidth : buttonHeight : @selector(oneButtonPressed) : UIControlEventTouchUpInside];

The value of oneButton is passed as value not as pointer (Which is Nil is other problem).

So what ever change you do with (UIButton *) button will not reflect to oneButton or other two.

So If you want to use different method to do this than return reference.

Try this:

- (UIButton *) setUpButton: (UIButtonType *) buttonType : (NSString *) title : (UIControlState *) controlState : (NSString *) font : (int) size : (double) xPos : (double) yPos : (double) width : (double) height : (SEL) selectorMethod :(UIControlEvents *) controlEvent
{
    UIButton * button = [UIButton buttonWithType:buttonType];
    button.frame = CGRectMake(xPos, yPos, width, height);
    [button setTitle:title controlState  ];
    [button addTarget:self action: selectorMethod forControlEvents:controlEvent];
    [self addSubview:button];
    button.titleLabel.font = [UIFont fontWithName:font size:size];
    return button;
}

And call It Like:

oneButton = [self setUpButton : UIButtonTypeRoundedRect : @"One" :UIControlStateNormal : @"Helvetica-Bold" : 20
                      : width - width/4 + 2 * initialWidth : height/3 + 6 * (buttonHeight + spaceBetweenButtons)
                      : width/4 - 2 * initialWidth : buttonHeight : @selector(oneButtonPressed) : UIControlEventTouchUpInside];

Comment me if you face any problem.

All the best....