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iOS---防止UIButton重复点击的三种实现方式

通常, 我们会采用如下的一些措施来防止重复点击UIButton:

使用UIButton的enabled或userInteractionEnabled

使用UIButton的enabled属性, 在点击后, 禁止UIButton的交互, 直到完成指定任务之后再将其enable即可.

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

// xxx

- (void)actionFixMultiClick_enabled:(UIButton *)sender {
    sender.enabled = NO;
    [self btnClickedOperations];
}

- (void)btnClickedOperations {
    self.view.backgroundColor = [UIColor colorWithRed:((arc4random() % 255) / 255.0)
                                                green:((arc4random() % 255) / 255.0)
                                                 blue:((arc4random() % 255) / 255.0)
                                                alpha:1.0f];

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        NSLog(@"btnClickedOperations");
        btn.enabled = YES;
    });
}

使用performSelector:withObject:afterDelay:和cancelPreviousPerformRequestsWithTarget

使用这种方式, 会在连续重复点击UIButton的时候, 自动取消掉之前的操作, 延时1s后执行实际的操作.

这样, 看起来会比第一种和第三种稍微延迟执行实际的操作.

[btn addTarget:self action:@selector(actionFixMultiClick_performSelector:) for

// xxx

- (void)actionFixMultiClick_performSelector:(UIButton *)sender {
    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(btnClickedOperations) object:nil];

    [self performSelector:@selector(btnClickedOperations) withObject:nil afterDelay:1];
}

使用runtime来对sendAction:to:forEvent:方法进行hook

UIControl的sendAction:to:forEvent:方法用于处理事件响应.如果我们在该方法的实现中, 添加针对点击事件的时间间隔相关的处理代码, 则能够做到在指定时间间隔中防止重复点击.

首先, 为UIButton添加一个Category:

@interface UIButton (CS_FixMultiClick)

@property (nonatomic, assign) NSTimeInterval cs_acceptEventInterval; // 重复点击的间隔

@property (nonatomic, assign) NSTimeInterval cs_acceptEventTime;

@end

Category不能给类添加属性, 所以以上的cs_acceptEventInterval和cs_acceptEventTime只会有对应的getter和setter方法, 不会添加真正的成员变量.

如果我们不在实现文件中添加其getter和setter方法, 则采用 btn.cs_acceptEventInterval = 1; 这种方法尝试访问该属性会出错.

2016-06-29 14:04:52.538 DemoRuntime[17380:1387981] -[UIButton setCs_acceptEventInterval:]: unrecognized selector sent to instance 0x7fe8e154e470

在实现文件中通过runtime的关联对象的方式, 为UIButton添加以上两个属性. 代码如下:

#import "UIControl+CS_FixMultiClick.h"
#import <objc/runtime.h>

@implementation UIButton (CS_FixMultiClick)

// 因category不能添加属性，只能通过关联对象的方式。
static const char *UIControl_acceptEventInterval = "UIControl_acceptEventInterval";

- (NSTimeInterval)cs_acceptEventInterval {
    return  [objc_getAssociatedObject(self, UIControl_acceptEventInterval) doubleValue];
}

- (void)setCs_acceptEventInterval:(NSTimeInterval)cs_acceptEventInterval {
    objc_setAssociatedObject(self, UIControl_acceptEventInterval, @(cs_acceptEventInterval), OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

static const char *UIControl_acceptEventTime = "UIControl_acceptEventTime";

- (NSTimeInterval)cs_acceptEventTime {
    return  [objc_getAssociatedObject(self, UIControl_acceptEventTime) doubleValue];
}

- (void)setCs_acceptEventTime:(NSTimeInterval)cs_acceptEventTime {
    objc_setAssociatedObject(self, UIControl_acceptEventTime, @(cs_acceptEventTime), OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}


// 在load时执行hook
+ (void)load {
    Method before   = class_getInstanceMethod(self, @selector(sendAction:to:forEvent:));
    Method after    = class_getInstanceMethod(self, @selector(cs_sendAction:to:forEvent:));
    method_exchangeImplementations(before, after);
}

- (void)cs_sendAction:(SEL)action to:(id)target forEvent:(UIEvent *)event {
    if ([NSDate date].timeIntervalSince1970 - self.cs_acceptEventTime < self.cs_acceptEventInterval) {
        return;
    }

    if (self.cs_acceptEventInterval > 0) {
        self.cs_acceptEventTime = [NSDate date].timeIntervalSince1970;
    }

    [self cs_sendAction:action to:target forEvent:event];
}

@end