textFieldShouldReturn: 方法无效化！

问题描述

问题代码

@interface ViewController : UIViewController<UITextFieldDelegate>//已经签订delegate
......
UITextField * tf;
tf.delegate = self;
tf = [[UITextField alloc]initWithFrame:CGRectMake(100, 100, 200, 50)];
[self.view addSubview:tf];
[tf setPlaceholder:@"hhee"];

问题原因

tf.delegate = self;

修改方案

UITextField * tf;
tf = [[UITextField alloc]initWithFrame:CGRectMake(100, 100, 200, 50)];
tf.delegate = self;
[self.view addSubview:tf];
[tf setPlaceholder:@"hhee"];