iOS自定义UIBarButtonItem的target和action示例代码

2022-05-15 07:33

短信预约 -IT技能 免费直播动态提醒

需求描述：

在项目开发过程中，遇到一种情况，需要自定义UIBarButtonItem，来实现分享样式，并在iPad中弹出系统分享框（UIActivityViewController），系统分享框需要指定显示位置（barButtonItem）。而自定义的UIBarButtonItem target指向的是UIButton。这与需求不符，需自定义UIBarButtonItem。

在介绍自定义UIBarButtonItem前，先介绍一下相关控件的子父类关系（也可以说继承关系）。

1、UIBarItem


NS_CLASS_AVAILABLE_IOS(2_0) @interface UIBarItem : NSObject <NSCoding, UIAppearance>

UIBarButtonItem


NS_CLASS_AVAILABLE_IOS(2_0) @interface UIBarButtonItem : UIBarItem <NSCoding>

UITabBarItem


NS_CLASS_AVAILABLE_IOS(2_0) @interface UITabBarItem : UIBarItem

下面是在界面上的显示效果

UIBarButtonItem和UITabBarItem效果显示

从上图中看到UIBarButtonItem有三种效果显示，分别是

导航左侧返回按钮，UINavigationItem中的backBarButtonItem属性


@property(nullable,nonatomic,strong) UIBarButtonItem *backBarButtonItem

纯文本的UIBarButtonItem


- (instancetype)initWithTitle:(nullable NSString *)title style:(UIBarButtonItemStyle)style target:(nullable id)target action:(nullable SEL)action;

纯图片的UIBarButtonItem，其中包括自定义图片和系统样式


- (instancetype)initWithImage:(nullable UIImage *)image style:(UIBarButtonItemStyle)style target:(nullable id)target action:(nullable SEL)action;


- (instancetype)initWithBarButtonSystemItem:(UIBarButtonSystemItem)systemItem target:(nullable id)target action:(nullable SEL)action;

UIToolBar使用UIBarButtonItem与导航效果一致。

关于UITabBarItem在这里就不多介绍，只是拿其显示效果与UIBarButtonItem对比。

在开发过程中，我们会使用到自定义UIBarButtonItem，来显示我们想要的界面效果。使用的方法常为：


- (instancetype)initWithCustomView:(UIView *)customView;


- (void)viewDidLoad {
 [super viewDidLoad];
 //自定义View
 UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 60.0, 40.0)];
 view.backgroundColor = [UIColor redColor];
 //自定义按钮
 UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
 btn.frame = view.bounds;
 [btn addTarget:self action:@selector(clickRight:) forControlEvents:UIControlEventTouchUpInside];
 [view addSubview:btn];
 //自定义Item
 UIBarButtonItem *barItem = [[UIBarButtonItem alloc] initWithCustomView:view];
 //
 self.navigationItem.leftBarButtonItem = barItem;
}

#pragma mark -

- (void)clickRight:(id)sender {
 NSLog(@"sender:%@",sender);
}

其中打印sender，其类型是UIButton。

2017-10-17 16:08:43.917 TestImage[5482:163865] sender:<UIButton: 0x7fb9bad12e60; frame = (0 0; 60 40); opaque = NO; layer = <CALayer: 0x61000003b940>>

通过上面描述，发现系统方法不能实现项目需求效果。当然也可以通过属性保存UIBarButtonItem方法来实现需求效果。即在点击按钮响应后，直接使用保存的UIBarButtonItem，但是我没有采用这种方法。

下面是我给出的两种解决方案:

方案一

继承UIBarButtonItem，实现子类。

定义子类


#import <UIKit/UIKit.h>

@interface LLBarButtonItem : UIBarButtonItem


@end


#import "LLBarButtonItem.h"

@implementation LLBarButtonItem

- (id)initWithCustomView:(UIView *)customView {
 self = [super initWithCustomView:customView];
 if (self) {
 UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
 btn.frame = customView.bounds;
 btn.backgroundColor = [UIColor clearColor];
 [btn addTarget:self action:@selector(clickButton:) forControlEvents:UIControlEventTouchUpInside];
 [customView addSubview:btn];
 }
 return self;
}

- (void)clickButton:(UIButton *)sender {
 if (self.target && [self.target respondsToSelector:self.action]) {
 //[self.target performSelector:self.action withObject:self];
 IMP imp = [self.target methodForSelector:self.action];
 
 void (*func)(id, SEL, id) = (void *)imp;
 
 func(self.target, self.action, self);
 }
}

@end

定义子类对象，调用子类对象


- (void)viewDidLoad {
 [super viewDidLoad];
 //自定义View
 UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 60.0, 40.0)];
 view.backgroundColor = [UIColor clearColor];
 //自定义Item
 LLBarButtonItem *barItem = [[LLBarButtonItem alloc] initWithCustomView:view];
 barItem.target = self;
 barItem.action = @selector(clickRight:);
 //
 self.navigationItem.leftBarButtonItem = barItem;
}

#pragma mark -

- (void)clickRight:(id)sender {
 NSLog(@"sender:%@",sender);
}

打印target对象

2017-10-17 16:24:11.696 TestImage[5557:170144] sender:<LLBarButtonItem: 0x7fb403c16080>

方案二

UIBarButtonItem类别

定义类别


#import <UIKit/UIKit.h>

@interface UIBarButtonItem (Custom)

- (void)addCutomTarget:(id)target action:(SEL)action;

@end


#import "UIBarButtonItem+Custom.h"

@implementation UIBarButtonItem (Custom)

- (void)addCutomTarget:(id)target action:(SEL)action {
 if (self.customView != nil) {
 self.target = target;
 self.action = action;
 //
 UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
 btn.frame = self.customView.bounds;
 btn.backgroundColor = [UIColor clearColor];
 [btn addTarget:self action:@selector(clickButton:) forControlEvents:UIControlEventTouchUpInside];
 [self.customView addSubview:btn];
 }
}

- (void)clickButton:(UIButton *)sender {
 if (self.target && [self.target respondsToSelector:self.action]) {
 //[self.target performSelector:self.action withObject:self];
 IMP imp = [self.target methodForSelector:self.action];
 
 void (*func)(id, SEL, id) = (void *)imp;
 
 func(self.target, self.action, self);
 }
}

@end

调用类别方法


- (void)viewDidLoad {
 [super viewDidLoad];
 //自定义View
 UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 60.0, 40.0)];
 view.backgroundColor = [UIColor clearColor];
 //自定义Item
 UIBarButtonItem *barItem = [[UIBarButtonItem alloc] initWithCustomView:view];
 [barItem addCutomTarget:self action:@selector(clickRight:)];
 //
 self.navigationItem.leftBarButtonItem = barItem;
}

#pragma mark -

- (void)clickRight:(id)sender {
 NSLog(@"sender:%@",sender);
}

打印target对象