iOS监听键盘弹出

在iOS开发过程中，监听键盘的弹出是十分常用的一项功能，可以有效地提升用户在使用过程中的体验

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概括的讲，监听键盘的弹出是很简单的一项功能，本质就是给当前的控制器添加两个观察者observer,一个监听键盘弹出，另一个监听键盘收起，然后相应的改变输入框和当前View的frame就可以了

• 下面可以用简洁的Demo示范一下（只改变输入框）

textView.PNG

- (void)viewDidLoad {
    
    [super viewDidLoad];

//  输入框
    UITextView *tf = [[UITextView alloc] initWithFrame:CGRectMake(10, 10, [UIScreen mainScreen].bounds.size.width - 20, 50)];
    
    tf.delegate = self;
    
    tf.backgroundColor = [UIColor orangeColor];
    
    [tf.layer setCornerRadius:6];
    
    [self.view addSubview:tf];
    
    //  添加观察者，监听键盘弹出
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyBoardDidShow:) name:UIKeyboardWillShowNotification object:nil];

    //  添加观察者，监听键盘收起
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyBoardDidHide:) name:UIKeyboardWillHideNotification object:nil];
    
    //  创建一个textView的容器View
    UIView *keyView = [[UIView alloc]initWithFrame:CGRectMake(0, [UIScreen mainScreen].bounds.size.height - 70, [UIScreen mainScreen].bounds.size.width, 70)];
    keyView.backgroundColor = [UIColor lightGrayColor];
    keyView.tag = 1000;
    
    [keyView addSubview:tf];
    
    [self.view addSubview:keyView];
}

• 以上的代码搭出了简单的界面，简单的示例一下弹出输入框，View的弹出此处就不示例了

键盘弹出的操作

- (void)keyBoardDidShow:(NSNotification*)notifiction {

    //获取键盘高度
    NSValue *keyboardObject = [[notifiction userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey];
    
    NSLog(@"%@",keyboardObject);
    
    CGRect keyboardRect;
    
    [keyboardObject getValue:&keyboardRect];
    
    //得到键盘的高度
    //CGRect keyboardRect = [[notification.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey]CGRectValue];
    
    // 取得键盘的动画时间，这样可以在视图上移的时候更连贯
    double duration = [[notifiction.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    NSLog(@"%f",duration);
    //调整放置有textView的view的位置
    
    //设置动画
    [UIView beginAnimations:nil context:nil];
    
    //定义动画时间
    [UIView setAnimationDuration:duration];
    [UIView setAnimationDelay:0];
    
    //设置view的frame，往上平移
    [(UIView *)[self.view viewWithTag:1000] setFrame:CGRectMake(0, [UIScreen mainScreen].bounds.size.height-keyboardRect.size.height-70, [UIScreen mainScreen].bounds.size.width, 70)];
    
    //提交动画
    [UIView commitAnimations];
}

键盘收起的操作

- (void)keyBoardDidHide:(NSNotification*)notification {

    //定义动画
    [UIView beginAnimations:nil context:nil];
     [UIView setAnimationDuration:0.25];
    
    //设置view的frame，往下平移
    [(UIView *)[self.view viewWithTag:1000] setFrame:CGRectMake(0, [UIScreen mainScreen].bounds.size.height - 70, [UIScreen mainScreen].bounds.size.width, 70)];
     [UIView commitAnimations];
}

供大家参考一下