iOS自定義UIBarButtonItem的target和action示例代碼

2020-07-26 02:21:15

字體：大中小

供稿：網(wǎng)友

需求描述：

在項目開發(fā)過程中，遇到一種情況，需要自定義UIBarButtonItem，來實現(xiàn)分享樣式，并在iPad中彈出系統(tǒng)分享框（UIActivityViewController），系統(tǒng)分享框需要指定顯示位置（barButtonItem）。而自定義的UIBarButtonItem target指向的是UIButton。這與需求不符，需自定義UIBarButtonItem。

在介紹自定義UIBarButtonItem前，先介紹一下相關(guān)控件的子父類關(guān)系（也可以說繼承關(guān)系）。

1、UIBarItem

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

2、UIBarButtonItem

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

3、UITabBarItem

NS_CLASS_AVAILABLE_IOS(2_0) @interface UITabBarItem : UIBarItem

下面是在界面上的顯示效果

UIBarButtonItem和UITabBarItem效果顯示

從上圖中看到UIBarButtonItem有三種效果顯示，分別是

1、導(dǎo)航左側(cè)返回按鈕，UINavigationItem中的backBarButtonItem屬性

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

2、純文本的UIBarButtonItem

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

3、純圖片的UIBarButtonItem，其中包括自定義圖片和系統(tǒng)樣式

- (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與導(dǎo)航效果一致。

關(guān)于UITabBarItem在這里就不多介紹，只是拿其顯示效果與UIBarButtonItem對比。

在開發(fā)過程中，我們會使用到自定義UIBarButtonItem，來顯示我們想要的界面效果。使用的方法常為：

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

- (void)viewDidLoad { [super viewDidLoad]; //自定義View UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 60.0, 40.0)]; view.backgroundColor = [UIColor redColor]; //自定義按鈕 UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom]; btn.frame = view.bounds; [btn addTarget:self action:@selector(clickRight:) forControlEvents:UIControlEventTouchUpInside]; [view addSubview:btn]; //自定義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，其類型是UIButton。

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

通過上面描述，發(fā)現(xiàn)系統(tǒng)方法不能實現(xiàn)項目需求效果。當然也可以通過屬性保存UIBarButtonItem方法來實現(xiàn)需求效果。即在點擊按鈕響應(yīng)后，直接使用保存的UIBarButtonItem，但是我沒有采用這種方法。

下面是我給出的兩種解決方案:

方案一

繼承UIBarButtonItem，實現(xiàn)子類。

定義子類

#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

定義子類對象，調(diào)用子類對象

- (void)viewDidLoad { [super viewDidLoad]; //自定義View UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 60.0, 40.0)]; view.backgroundColor = [UIColor clearColor]; //自定義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對象

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

方案二

UIBarButtonItem類別

定義類別

#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

調(diào)用類別方法

- (void)viewDidLoad { [super viewDidLoad]; //自定義View UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 60.0, 40.0)]; view.backgroundColor = [UIColor clearColor]; //自定義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對象