键盘的弹出和隐藏

知识补充

---利用通知的方法监听键盘位置的改变

代码：

#import "ViewController.h"
@interface ViewController ()
// 获得TextField属性
@property (weak, nonatomic) IBOutlet UITextField *textField;
// 获得TextField的底部间距属性
@property (weak, nonatomic) IBOutlet NSLayoutConstraint *bottomSpace;
@end
@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    // 利用通知，监听键盘的位置
    // 添加监听
//    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyBoardWillShow:) name:UIKeyboardWillShowNotification object:nil];
//    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyBoardWillHide:) name:UIKeyboardWillHideNotification object:nil];
    // 最常用的通知
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyBoardWillChange:) name:UIKeyboardWillChangeFrameNotification object:nil];
}
- (void)dealloc{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}
- (void)keyBoardWillChange:(NSNotification *)note{
    // 获取键盘的frame
    CGRect frame = [note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
    // 获得键盘的动画时间
    CGFloat time = [UIKeyboardAnimationDurationUserInfoKey doubleValue];
    // 修改textfield的底部约束（屏幕的高度 - 键盘的最后Y值）
    [UIView animateWithDuration:time animations:^{
        self.bottomSpace.constant = self.view.frame.size.height - frame.origin.y;
        [self.view layoutIfNeeded];
    }];
}
//- (void)keyBoardWillShow:(NSNotification *)note{
//
//    // 取出键盘的frame
//    CGRect frame = [note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
//    // 修改textField的底部约束
//    
//    CGFloat time = [UIKeyboardAnimationDurationUserInfoKey doubleValue];
//    [UIView animateWithDuration:time animations:^{
//        self.bottomSpace.constant = frame.size.height;
//        [self.view layoutIfNeeded];
//    }];
//    
//}
//
//- (void)keyBoardWillHide:(NSNotification *)note{
//
//    CGFloat time = [UIKeyboardAnimationDurationUserInfoKey doubleValue];
//    [UIView animateWithDuration:time animations:^{
//        self.bottomSpace.constant = 0;
//        [self.view layoutIfNeeded];
//    }];
//    
//}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    // 点击屏幕的时候隐藏键盘
//    [self.textField resignFirstResponder];
//    [self.textField endEditing:YES];
    [self.view endEditing:YES];
}
@end