UIBarButtonItem setBackgroundImage forState barMetrics example in Objective C (iOS).

UIBarButtonItem setBackgroundImage forState barMetrics

Sets the background image for a given state and bar metrics.

- (void)setBackgroundImage:(UIImage *)backgroundImage forState:(UIControlState)state barMetrics:(UIBarMetrics)barMetrics

Parameters of [UIBarButtonItem setBackgroundImage forState barMetrics]
backgroundImage
The background image for the specified state and metrics.
state
A control state.
barMetrics
Bar metrics.

Discussion of [UIBarButtonItem setBackgroundImage forState barMetrics]
For good results, backgroundImage must be a stretchable image.

UIBarButtonItem setBackgroundImage forState barMetrics example.

UIBarButtonItem *btnDone = [[UIBarButtonItem alloc] initWithTitle:@"I am done" style:UIBarButtonItemStyleBordered target:self action:nil];
UIImage *stretchable = [[UIImage imageNamed:@"StretchableImage.png"] stretchableImageWithLeftCapWidth:10 topCapHeight:16];
[btnDone setBackgroundImage:stretchable forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[self.navigationItem setRightBarButtonItem:btnDone];

Example of [UIBarButtonItem setBackgroundImage forState barMetrics].

- (void) __setStyle:(UIBarButtonItemStyle)style {
    [self __setStyle:style];

    if(style == UIBarButtonItemStyleDone) {
        [self setBackgroundImage:[[UIImage imageNamed:@"customDoneButton"] resizableImageWithCapInsets: UIEdgeInsetsMake(8, 8, 8, 8)]
                        forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
        [self setBackgroundImage:[UIImage imageNamed:@"customDoneButtonClicked"]
                        forState:UIControlStateHighlighted barMetrics:UIBarMetricsDefault];
    } else {
        [self setBackgroundImage:[[UIImage imageNamed:@"customButton"] resizableImageWithCapInsets: UIEdgeInsetsMake(8, 8, 8, 8)]
                        forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
        [self setBackgroundImage:[UIImage imageNamed:@"customButtonHighlighted"]
                        forState:UIControlStateHighlighted barMetrics:UIBarMetricsDefault];
    }
}

UIBarButtonItem setBackgroundImage forState barMetrics example.

+ (UIBarButtonItem *)createSquareBarButtonItemWithTitle:(NSString *)t target:(id)tgt action:(SEL)a
{
    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    // Since the buttons can be any width we use a thin image with a stretchable center point
    UIImage *buttonImage = [[UIImage imageNamed:@"SquareButton.png"] stretchableImageWithLeftCapWidth:5 topCapHeight:0];
    UIImage *buttonPressedImage = [[UIImage imageNamed:@"SquareButton_pressed.png"] stretchableImageWithLeftCapWidth:5 topCapHeight:0];

    [[button titleLabel] setFont:[UIFont boldSystemFontOfSize:12.0]];
    [button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [button setTitleColor:[UIColor whiteColor] forState:UIControlStateHighlighted];
    [button setTitleShadowColor:[UIColor colorWithWhite:1.0 alpha:0.7] forState:UIControlStateNormal];
    [button setTitleShadowColor:[UIColor clearColor] forState:UIControlStateHighlighted];
    [[button titleLabel] setShadowOffset:CGSizeMake(0.0, 1.0)];

    CGRect buttonFrame = [button frame];
    buttonFrame.size.width = [t sizeWithFont:[UIFont boldSystemFontOfSize:12.0]].width + 24.0;
    buttonFrame.size.height = buttonImage.size.height;
    [button setFrame:buttonFrame];

    [button setBackgroundImage:buttonImage forState:UIControlStateNormal];
    [button setBackgroundImage:buttonPressedImage forState:UIControlStateHighlighted];

    [button setTitle:t forState:UIControlStateNormal];

    [button addTarget:tgt action:a forControlEvents:UIControlEventTouchUpInside];

    UIBarButtonItem *buttonItem = [[UIBarButtonItem alloc] initWithCustomView:button];

    return [buttonItem autorelease];
}

End of UIBarButtonItem setBackgroundImage forState barMetrics example article.