如何获取页面上的第一响应者

#import <UIKit/UIKit.h>

@interface UIResponder (FirstResponder)
+ (id)currentFirstResponder; 
@end

#import "UIResponder+FirstResponder.h"

static __weak id currentFirstResponder;
@implementation UIResponder (FirstResponder)
+ (id)currentFirstResponder {
    currentFirstResponder = nil;
    [[UIApplication sharedApplication] sendAction:@selector(findFirstResponder:) to:nil from:nil forEvent:nil];
    return currentFirstResponder;
}

- (void)findFirstResponder:(id)sender {
    currentFirstResponder = self;
}
@end

使用

//获取当前的第一响应者
    id re =  [UIResponder currentFirstResponder];
//辞退第一响应者
    [re resignFirstResponder];