iOS对键盘的处理

方法１.　使用<UITextFeildDelegate>,使用的UITextField示例 设置其Delegate为self，点击return按钮隐藏键盘。实现函数如下：

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

return YES;
   }

方法2. 点击界面的其它空白地方隐藏
     由于UIViewController是继承自UIResponder的，所以可以覆写- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;这个开始触摸的方法来取消第一响应者，代码如下：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

[_tfPassword resignFirstResponder];

[_tfUsername resignFirstResponder];

}

以上两种方法是初学iOS的时候使用的。

3. 最好还是使用NotificationCenter的方法比较好，能获取键盘高度等详细信息

#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UITextField *tfTest;
@property (weak, nonatomic) IBOutlet UITextField *tfTest2;
@end

@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
}

- (void)viewDidappear:(BOOL)animated
{
    [super viewDidDisappear:animated];
    //移除键盘监听消息
    [[NSNotificationCenter defaultCenter]removeObserver:self name:UIKeyboardWillShowNotificationobject:nil];
    [[NSNotificationCenter defaultCenter]removeObserver:self name:UIKeyboardWillHideNotificationobject:nil];
    //注册键盘监听消息
    [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyShow:)name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyHide:)name:UIKeyboardWillHideNotification object:nil];
}

//弹出键盘消息响应
- (void)keyShow:(NSNotification *)no
{
    NSLog(@"keyShow");

    NSDictionary *dic = [no valueForKey:@"userInfo"];
    CGFloat heightKeyboard = [[dicvalueForKey:@"UIKeyboardBoundsUserInfoKey"]CGRectValue].size.height;

    UIView *firstResponderView = [self getFirstResponderView];
    CGFloat distanceToBottom = self.view.frame.size.height -CGRectGetMaxY(firstResponderView.frame);

    //动画
    if(distanceToBottom < heightKeyboard){
        CGRect frame = self.view.frame;
        frame.origin.y = -(heightKeyboard - distanceToBottom);
        [UIView animateWithDuration:0.3f animations:^{
            [self.view setFrame:frame];
        } completion:^(BOOL finished) {
        }];
    }
}

//关闭键盘消息响应
- (void)keyHide:(NSNotification *)no
{
    NSLog(@"keyHide");
    CGRect frame = self.view.frame;
    frame.origin.y = 0;

    //动画
    [UIView animateWithDuration:0.3f animations:^{
        [self.view setFrame:frame];
    } completion:^(BOOL finished) {
    }];
}

//点击背景区域自动隐藏键盘
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    UIView *firstResponderView = [self getFirstResponderView];
    [firstResponderView resignFirstResponder];
}

//获取当前焦点所在的控件
- (UIView *)getFirstResponderView{
    UIWindow *keyWindow = [[UIApplication sharedApplication]keyWindow];
    UIView *firstResponder = [keyWindow performSelector:@selector(firstResponder)];
    return firstResponder;
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
}
@end