自适应UITextView和键盘位置

来源：互联网发布：排序算法有几种编辑：程序博客网时间：2024/05/29 01:52

在UITextView输入时视图被键盘挡住，这可是非常常见的事，这里说一个解决方案。

基本思想就是在键盘将要出现时设置UITextView的frame在弹出的键盘之上，在键盘将要消失时重置UITextView的位置。

首先在消息中心中注册自己为事件观察者：

#pragma mark - View life cycle- (void)viewDidLoad {    [super viewDidLoad];        self.textView.keyboardDismissMode = UIScrollViewKeyboardDismissModeInteractive;}- (void)viewDidAppear:(BOOL)animated {    // 当键盘出现时发送消息给self    [[NSNotificationCenter defaultCenter] addObserver:self                                             selector:@selector(keyboardWillShow:)                                                 name:UIKeyboardWillShowNotification                                               object:nil];        // 当键盘消失时发送消息给self    [[NSNotificationCenter defaultCenter] addObserver:self                                             selector:@selector(keyboardWillHide:)                                                 name:UIKeyboardWillHideNotification                                               object:nil];}- (void)viewDidDisappear:(BOOL)animated {    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];}

然后是对应的方法：

#pragma mark - Keyboard management- (void)keyboardWillShow:(NSNotification *)noti {    [UIView beginAnimations:nil context:nil];    [UIView setAnimationDuration:0.5];        CGSize keyboardSize = [[[noti userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;    CGFloat height = keyboardSize.height;    self.textView.frame = CGRectMake(0.0,                                     20.0,                                     self.view.bounds.size.width,                                     self.view.bounds.size.height - height - 20.0);        [UIView commitAnimations];}- (void)keyboardWillHide:(NSNotification *)noti {    [UIView beginAnimations:nil context:nil];    [UIView setAnimationDuration:0.1];        self.textView.frame = CGRectMake(0.0, 20.0, self.view.bounds.size.width, self.view.bounds.size.height - 20.0);        [UIView commitAnimations];}

为了让键盘出现得自然点，这里加了点动画。

也可以将其写成宏，让代码更加简洁：

#define TEXTVIEW_DEFAULT_FRAME CGRectMake(0.0, 20.0, self.view.bounds.size.width, self.view.bounds.size.height - 20.0)#define ADJUST_TEXTVIEW_FRAME(nofi) \CGRectMake(0.0, 20.0, \self.view.bounds.size.width, \self.view.bounds.size.height -\[[[noti userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size.height - 20.0)

TEXTVIEW_DEFAULT_FRAME表示默认情况下的位置，ADJUST_TEXTVIEW_FRAME表示键盘出现后进行调整的位置。

修改后代码为：

#pragma mark - Keyboard management- (void)keyboardWillShow:(NSNotification *)noti {    [UIView beginAnimations:nil context:nil];    [UIView setAnimationDuration:0.5];    self.textView.frame = ADJUST_TEXTVIEW_FRAME(noti);    [UIView commitAnimations];}- (void)keyboardWillHide:(NSNotification *)noti {    [UIView beginAnimations:nil context:nil];    [UIView setAnimationDuration:0.1];    self.textView.frame = TEXTVIEW_DEFAULT_FRAME;    [UIView commitAnimations];}

尝试下运行：

不足之处：

这里UITextView中隐藏键盘的方法是UIScrollViewKeyboardDismissModeInteractive，在隐藏键盘时如果有下滑手势，那么在TextView和键盘之间将会出现一段空白：

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