键盘的通知 使文本框跟随键盘移动

一、前期工作  定义全局变量的文本框 和 分别宏定义屏幕的宽和高

#define SCREEN_HEIGHT CGRectGetHeight([UIScreen mainScreen].bounds)
#define SCREEN_WIDTH CGRectGetWidth([UIScreen mainScreen].bounds)

@interface ViewController ()<UITextFieldDelegate>
{
    UITextField *myTextFileld;
}

myTextFileld = [[UITextField alloc]initWithFrame:CGRectMake(0, SCREEN_HEIGHT-40, SCREEN_WIDTH,40 )];
    myTextFileld.placeholder = @"请输入内容";
    myTextFileld.delegate = self;
    myTextFileld.borderStyle = UITextBorderStyleRoundedRect;
    [self.view addSubview:myTextFileld];

二 、 分别给键盘的两个状态增加通知观察者

 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(KeyBordAction:) name:UIKeyboardWillShowNotification object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(KeyBordAction:) name:UIKeyboardWillHideNotification object:nil];

调用的方法

- (void)KeyBordAction:(NSNotification *)not{
    NSDictionary *info = not.userInfo;
    CGRect frame = [info[UIKeyboardFrameEndUserInfoKey] CGRectValue];
    CGFloat y = CGRectGetMinY(frame);
    myTextFileld.frame = CGRectMake(0, y-40, SCREEN_WIDTH, 40);
}

文本框的代理方法

- (BOOL)textFieldShouldReturn:(UITextField *)textField{
    [textField resignFirstResponder];
    return YES;
}