ios - UIImage resizableImageWithCapInsets - 这可以使用 Nib 指定吗？

Question

我有一个 UIImage 使用 resizableImageWithCapInsets 完美调整大小来制作包含文本标签的角标(Badge)。我很想知道有没有办法在 Storyboard或使用 Nib 创建的 View 中执行此操作？

没有技术理由要求这样做。大部分 UI 是在 Nib 中完成的，我想尽可能多地保留在那里，而不是加载图像、使其可调整大小、查找文本尺寸、调整 UIImageView 大小，然后在代码中应用标签。

我还不能使这个项目仅限 iOS6(部署目标 ios5+)，所以使用布局约束不是一个选项。

Answer 1

是的，有。

诀窍是覆盖 -initWithCoder: 和图像 setter (setImage:forState: 和 setBackgroundImage:forState:)来创建您在 xib 中设置的相同图像的可调整大小版本。显然，它们仍然不会在 xib 本身中正确调整大小，但会在初始化后正确调整大小。不要忘记将 NAResizableButton 设置为 UIButton 的自定义类。

当然胜过以编程方式进行。 :)

接口(interface):

#import <UIKit/UIKit.h>

@interface NAResizableButton : UIButton

@end

实现:

#import "NAResizableButton.h"

@implementation NAResizableButton

- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if (self)
    {
        [self setImage:[self imageForState:UIControlStateNormal] forState:UIControlStateNormal];
        [self setImage:[self imageForState:UIControlStateHighlighted] forState:UIControlStateHighlighted];
        [self setImage:[self imageForState:UIControlStateSelected] forState:UIControlStateSelected];
        [self setImage:[self imageForState:UIControlStateDisabled] forState:UIControlStateDisabled];

        [self setBackgroundImage:[self backgroundImageForState:UIControlStateNormal] forState:UIControlStateNormal];
        [self setBackgroundImage:[self backgroundImageForState:UIControlStateHighlighted] forState:UIControlStateHighlighted];
        [self setBackgroundImage:[self backgroundImageForState:UIControlStateSelected] forState:UIControlStateSelected];
        [self setBackgroundImage:[self backgroundImageForState:UIControlStateDisabled] forState:UIControlStateDisabled];
    }
    return self;
}

- (void)setImage:(UIImage *)inImage forState:(UIControlState)inState
{
    UIEdgeInsets edgeInsets = UIEdgeInsetsMake(ceilf(inImage.size.height / 2), ceilf(inImage.size.width / 2), ceilf(inImage.size.height / 2), ceilf(inImage.size.width / 2));
    if ([inImage respondsToSelector:@selector(resizableImageWithCapInsets:)])
    {
        // iOS 5
        inImage = [inImage resizableImageWithCapInsets:edgeInsets];
    }
    else
        inImage = [inImage stretchableImageWithLeftCapWidth:edgeInsets.left topCapHeight:edgeInsets.top];

    [super setImage:inImage forState:inState];
}

- (void)setBackgroundImage:(UIImage *)inImage forState:(UIControlState)inState
{
    UIEdgeInsets edgeInsets = UIEdgeInsetsMake(ceilf(inImage.size.height / 2), ceilf(inImage.size.width / 2), ceilf(inImage.size.height / 2), ceilf(inImage.size.width / 2));
    if ([inImage respondsToSelector:@selector(resizableImageWithCapInsets:)])
    {
        // iOS 5
        inImage = [inImage resizableImageWithCapInsets:edgeInsets];
    }
    else
        inImage = [inImage stretchableImageWithLeftCapWidth:edgeInsets.left topCapHeight:edgeInsets.top];

    [super setBackgroundImage:inImage forState:inState];
}

@end