无法在UITableViewCell中以编程方式创建的UIButton上设置图像

Question

I have a custom UITableViewCell that's defined in a storyboard, and I'm programmatically creating a UIButton within each cell (in awakeFromNib). (So much for refactoring.)

I seem unable to set the image on that button. The image is present in an asset catalog and I'm able to set it on buttons in other (non-tableview) views. And the button is created properly and works properly. But the image does not appear, and when I pause the simulator and examine the exploded view, the button shows "no image" in the sidebar. I'm a bit stumped.

Relevant code (from the UITableViewCell subclass):

- (id)initWithCoder:(NSCoder *)aDecoder {
    if (self) {
        self = [super initWithCoder:aDecoder];
        viewsDict = [[NSMutableDictionary alloc] initWithCapacity:24]; // for constraints
    }
}

- (void)awakeFromNib {
    [super awakeFromNib];

    [self.contentView addSubview:self.heartButton]; // instantiates the button (see below)
    [[self.heartButton superview] bringSubviewToFront:self.heartButton];

    [viewsDict setObject:self.heartButton forKey:@"heartButton"];
    [viewsDict setObject:self.containerView forKey:@"containerView"];

    // constraints
    [self.heartButton addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[heartButton(32)]" options:0 metrics:nil views:viewsDict]];
    [self.heartButton addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:[heartButton(32)]" options:0 metrics:nil views:viewsDict]];
    [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-8-[heartButton]" options:0 metrics:nil views:viewsDict]];
    [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[containerView][heartButton]" options:0 metrics:nil views:viewsDict]];
}

- (UIButton *)heartButton {
    if (_heartButton == nil) {
        _heartButton = [UIButton buttonWithType:UIButtonTypeCustom];
        [_heartButton setTranslatesAutoresizingMaskIntoConstraints:NO];
        SEL selector = NSSelectorFromString(@"heartButtonTapped:");
        [_heartButton addTarget:self action:selector forControlEvents:UIControlEventTouchUpInside];
        [_heartButton setImage:[UIImage imageNamed:@"heart"] forState:UIControlStateNormal | UIControlStateHighlighted];
    }
    return _heartButton;
}

- (IBAction)heartButtonTapped:(id)sender {
    NSLog(@"This gets logged when the button gets tapped");
}

I'm sure it's something terribly obvious. Please embarrass me.

Answer 1

The problem is in here.

[_heartButton setImage:[UIImage imageNamed:@"heart"] forState:UIControlStateNormal | UIControlStateHighlighted];

You have to set those two statues by two lines as below.

[_heartButton setImage:[UIImage imageNamed:@"heart"] forState:UIControlStateNormal];
[_heartButton setImage:[UIImage imageNamed:@"heart"] forState:UIControlStateHighlighted];