编程技巧 - Button多参数点击

iOS 原生的 UIButton 点击事件是不允许带多参数的，唯一的一个参数就是默认UIButton本身

那么我们该怎么实现传递多个参数的点击事件呢？

1.如果业务场景非常简单，要求传单参数并且是整数类型，可以用tag

[cell.deleteButton setTag:indexPath.row];  //例如，将cell的行数设置成tag

2.利用ObjC关联，runtime之所以被称为iOS 的动态特性是有道理的，当然关联甚至可以帮助NSArray等其他对象实现“多参数传递”

实现起来也非常简便：

UIButton *btn = // create the button
objc_setAssociatedObject(btn, "firstObject", someObject, OBJC_ASSOCIATION_RETAIN_NONATOMIC);   //实际上就是KVC
objc_setAssociatedObject(btn, "secondObject", otherObject, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

[btn addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];

- (void)click:(UIButton *)sender
{
id first = objc_getAssociatedObject(btn, "firstObject");		//取参
id second = objc_setAssociatedObject(btn, "secondObject");
// etc.
}

3.利用自定义，添加一个多参数的字典属性变量即可（为什么要字典？可以装多多的）

自定义Button子类，甚至都不用重写啥的：

@interface MultiParamButton : UIButton

@property (nonatomic, strong) NSDictionary* multiParamDic;

@end

传参：

NSDictionary* paramDic = @{@"one":@"one", @"two":@2, @"third":@(3)};

MultiParamButton* multiParamButton = [[MultiParamButton alloc] init];
[multiParamButton setFrame:CGRectMake(0, 0, 50, 50)];
multiParamButton.center = self.view.center;
[multiParamButton setBackgroundColor:[UIColor grayColor]];
[multiParamButton addTarget:self action:@selector(multiParamButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:multiParamButton];

multiParamButton.multiParamDic = paramDic;

点击：

- (void)multiParamButtonClicked:(UIButton* )button
{
MultiParamButton* multiParamButton = (MultiParamButton* )button;

NSLog(@"Vvvverify : %@", multiParamButton.multiParamDic);
}

爽爽的：



当然，如果用扩展，然后添加property后重写GetSet也是一样一样的

4.完全不在Button上入手，针对业务来，最常见的就是在TableViewCell上面的Button，这种存在（视图）继承树之间的传递，这里举个简单的例子

Button获取所属父视图的所属视图控制器的参数，间接传参

#import "LBMultiParamButtonController.h"

#import "MultiParamButton.h"

@interface LBMultiParamButtonController ()

@property (nonatomic, strong) NSDictionary* paramDic;

@end

@implementation LBMultiParamButtonController

- (id)init
{
self = [super init];

if (self)
{
_paramDic = @{@"one":@"one", @"two":@2, @"third":@(3)};
}

return self;
}

- (void)viewDidLoad
{
[super viewDidLoad];

UIButton* button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setFrame:CGRectMake(0, 0, 50, 50)];
[button setCenter:self.view.center];
[button setBackgroundColor:[UIColor grayColor]];
[button addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:button];
}

- (void)buttonClicked:(UIButton* )button
{

LBMultiParamButtonController* multiParamButtonController = nil;

//获取button所属的视图控制器，如果视图控制器都能获取，还有什么不能获取呢？
for(UIView* next = [button superview]; next; next = next.superview)
{
UIResponder *nextResponder = [next nextResponder];

if ([nextResponder isKindOfClass:[LBMultiParamButtonController class]])
{
multiParamButtonController = (LBMultiParamButtonController* )nextResponder;

break;
}
}

NSLog(@"param : %@", multiParamButtonController.paramDic);
}

@end

这种非常多的用在UITableViewCell上自定义的按钮的参数的情况！

5.利用Delegate和performSelector:withObject:withObject  方法可以传递最多两个参数：

定义protocol：

#pragma mark - SYAccountListCellDelegate.

@class SYAccountListCell;

@protocol  SYAccountListCellDelegate <NSObject>

- (void)accountListCell:(SYAccountListCell* )cell didTapButton:(UIButton* )button;

@end

自定义Cell的时候将你想传的东西传进入，这里用cell和button做例子：

@implementation SYAccountListCell

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];

if (self)
{

self.deleteButton = [UIButton buttonWithType:UIButtonTypeCustom];
[self.deleteButton setFrame:CGRectMake(225,
5,
40,
40)];
[self.deleteButton setBackgroundColor:[UIColor redColor]];
[self.deleteButton addTarget:self action:@selector(deleteButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
[self.contentView addSubview:self.deleteButton];
}

return self;
}

- (void)deleteButtonClicked:(UIButton* )button
{
if ([self.delegate respondsToSelector:@selector(accountListCell:didTapButton:)])
{
[self.delegate performSelector:@selector(accountListCell:didTapButton:) withObject:self withObject:button];
}
}

@end

Delegate实现：

#pragma mark - SYAccountListCellDelegate.

- (void)accountListCell:(SYAccountListCell *)cell didTapButton:(UIButton *)button
{
NSLog(@"Cell : %@ , Button : %@", cell, button);
}

虽然有点曲折，但是传参效果非常到位

这里补充一下，这里的最多两个参数是直面的参数个数，如果将参数设置位结构体，那么就皆大欢喜啦，想怎么传就怎么传！

6.利用Block 和  关联 ， 直接可以当前点击并且操作参数 － 强！

#import <UIKit/UIKit.h>

typedef void (^ActionBlock)();

@interface UIButton (Utility)

@property (readonly) NSMutableDictionary *event;

- (void) handleControlEvent:(UIControlEvents)controlEvent withBlock:(ActionBlock)action;

@end

实现文件：

#import <objc/runtime.h>
#import "UIButton+Utility.h"

@implementation UIButton (Utility)

static char overviewKey;

@dynamic event;

- (void)handleControlEvent:(UIControlEvents)event withBlock:(ActionBlock)block
{
objc_setAssociatedObject(self, &overviewKey, block, OBJC_ASSOCIATION_COPY_NONATOMIC);

[self addTarget:self action:@selector(callActionBlock:) forControlEvents:event];
}

- (void)callActionBlock:(id)sender
{
ActionBlock block = (ActionBlock)objc_getAssociatedObject(self, &overviewKey);

if (block)
{
block();
}
}

@end

操作：

[button handleControlEvent:UIControlEventTouchUpInside withBlock:^{

NSLog(@"ssss : %@", self.paramDic);

}];

转别人的，超强耶！

目前就这6种比较容易实现的传参方式，写这个其实最重要的不是实现的效果，而是我在网上搜集资料的时候看到很多人说，系统不支持，所以不可行，甚至连关联那么简单的都不试试，学技术的态度就是应该直接地，间接地，不断去尝试，才能有收获！！