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前面博客有讲触摸事件提过响应事件和响应者链，而管理响应者链的正是UIResponder。
一、代码
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSLog(@"window:%@",[self.window nextResponder]);
NSLog(@"AppDelegate: %@",[self nextResponder]);
return YES;
}
//
// ViewController.m
// UIResponder
//
// Created by cyw on 15-5-16.
// Copyright (c) 2015年 cyw. All rights reserved.
//
#import "ViewController.h"
@interface ViewController ()<UITextFieldDelegate>
@end
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
UITextField *textField=[[UITextField alloc]init];
textField.frame=CGRectMake(100, 100, 100, 40);
textField.borderStyle=UITextBorderStyleLine;
textField.backgroundColor=[UIColor redColor];
textField.delegate=self;
textField.tag=10001;
BOOL canBecomeFirstResponder=[textField canBecomeFirstResponder ];
BOOL canResignFirstResponder=[textField canResignFirstResponder];
NSLog(@"%d %d",canBecomeFirstResponder,canResignFirstResponder);
[textField becomeFirstResponder];
[self.view addSubview:textField];
UITextField *textField1=[[UITextField alloc]init];
textField1.frame=CGRectMake(100, 200, 100, 40);
textField1.borderStyle=UITextBorderStyleLine;
textField1.backgroundColor=[UIColor redColor];
textField1.delegate=self;
textField1.tag=10002;
[self.view addSubview:textField1];
UIResponder *responder1= [textField nextResponder];
UIResponder *responder2=[self nextResponder];
UIResponder *responder3=[self.view nextResponder];
NSLog(@"textField:%@\nViewController:%@\nself.view:%@",responder1,responder2,responder3);
}
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
BOOL isFirstResponder= [textField isFirstResponder];
NSLog(@"textField%d isFirstResponder %d:",textField.tag,isFirstResponder);
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
二、结果
2015-05-17 00:30:02.427 UIResponder[1132:60b] window:<UIApplication: 0x8d71b80> 2015-05-17 00:30:02.437 UIResponder[1132:60b] AppDelegate: (null) 2015-05-17 00:30:02.446 UIResponder[1132:60b] 1 1 2015-05-17 00:30:02.449 UIResponder[1132:60b] textField:<UIView: 0x8e742d0; frame = (0 0; 320 480); autoresize = RM+BM; layer = <CALayer: 0x8e739e0>> ViewController:(null) self.view:<ViewController: 0x8c9b8c0> 2015-05-17 00:30:02.463 UIResponder[1132:60b] textField10001 isFirstResponder 1:
三、由上面的输出结果有一点比较纳闷，为什么ViewController返回的是NULL？我想了半天也没想到什么原因，也请高手给指点一下
四、其实UIResponder不仅仅只有这些，具体可以参考:http://southpeak.github.io/blog/2015/03/07/uiresponder/?utm_source=tuicool
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原文地址：http://www.cnblogs.com/cuiyw/p/4508876.html
