如何按状态设置UIButton背景颜色

Question

我们知道,UIButton提供基于的图像设置器UIControlState.但似乎它没有提供基于的设置背景颜色UIControlState.
怎么做？

Answer 1

获取一个UIImage从UIColor使用该图像作为背景图像按钮.

- (UIImage *)imageWithColor:(UIColor *)color
{
    CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, rect);

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return image;
}

[button setBackgroundImage:[self imageWithColor:[UIColor lightGrayColor]] forState:UIControlStateNormal];
[button setBackgroundImage:[self imageWithColor:[UIColor redColor]] forState:UIControlStateHighlighted];

Answer 2

是的，这是正确的……您需要在UIButton子类中处理它。

这是我使用的StyleKitButton,UIButton子类。它将每个模式的背景颜色存储在一个字典中，然后一些奇特的处理让触摸正确转换。

用法

StyleKitButton *button = [[StyleKitButton alloc] init];
button.layer.borderColor = [UIColor blue].CGColor;

[button setTitleColor:[UIColor white] forState:UIControlStateNormal];
[button setBackgroundColor:[UIColor blue] forState:UIControlStateNormal];

[button setTitleColor:[UIColor white] forState:UIControlStateHighlighted];
[button setBackgroundColor:[UIColor purple] forState:UIControlStateHighlighted];

班级：

#import <UIKit/UIKit.h>

@interface StyleKitButton : UIButton

@end

//------------------------------------------------------


#import "StyleKitButton.h"

@interface StyleKitButton()

@property (nonatomic, strong) NSMutableDictionary *backgroundColors;

@end

@implementation StyleKitButton

#pragma mark - Background Colors

- (void)setBackgroundColor:(UIColor *)backgroundColor forState:(UIControlState)state {
    if (!self.backgroundColors) {
        self.backgroundColors = [[NSMutableDictionary alloc] init];
    }

    if (backgroundColor) {
        self.backgroundColors[@(state)] = backgroundColor;
    }

    if (state == UIControlStateNormal) {
        self.backgroundColor = backgroundColor;
    }
}

- (void)transitionBackgroundToColor:(UIColor*)color {
    CATransition *animation = [CATransition animation];
    animation.type = kCATransitionFade;
    [animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
    [self.layer addAnimation:animation forKey:@"EaseOut"];
    self.backgroundColor = color;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];

    UIColor *selectedColor = self.backgroundColors[@(UIControlStateHighlighted)];
    if (selectedColor) {
        [self transitionBackgroundToColor:selectedColor];
    }
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesCancelled:touches withEvent:event];

    UIColor *normalColor = self.backgroundColors[@(UIControlStateNormal)];
    if (normalColor) {
        [self transitionBackgroundToColor:normalColor];
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesEnded:touches withEvent:event];

    UIColor *normalColor = self.backgroundColors[@(UIControlStateNormal)];
    if (normalColor) {
        [self transitionBackgroundToColor:normalColor];
    }
}

@end