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标题: iOS 键盘显示事件处理 [打印本页]

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作者: 菜鸟教程小白    时间: 2022-12-13 10:54
标题: iOS 键盘显示事件处理

我正在开发一个聊天应用程序，其中我有一个 TextView (不是文本字段)，当我点击它时，键盘应该显示并且所有内容都应该向上移动。

到目前为止，我已经设法将表格 View 和 TextView 的框架向上移动并使用以下代码显示键盘。

- (void)keyboardWasShownNSNotification *)notification {

    NSDictionary* info = [notification userInfo];

    keyboardSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    CGPoint contentViewOrigin = self.contentView.frame.origin;

    CGFloat contentViewHeight = self.contentView.frame.size.height;

    CGRect visibleRect = self.view.frame;

    visibleRect.size.height -= keyboardSize.height;
    BOOL up = CGRectContainsPoint(visibleRect, contentViewOrigin);

    if (!up){


    self.tableView.frame = CGRectMake(self.tableView.frame.origin.x,self.tableView.frame.origin.y,self.tableView.frame.size.width,280.0f);


    self.contentView.frame = CGRectOffset(self.contentView.frame, 0, 0 - keyboardSize.height);

    if([self.tableView numberOfRowsInSection:0]!=0)
    {
        NSIndexPath* ip = [NSIndexPath indexPathForRow:[self.tableView numberOfRowsInSection:0]-1 inSection:0];
        [self.tableView scrollToRowAtIndexPath:ip atScrollPosition:UITableViewScrollPositionBottom animated:UITableViewRowAnimationLeft];
    }


}

}

- (void)keyboardWillBeHiddenNSNotification *)notification {

self.contentView.frame = originalContentView;
self.tableView.frame = originalTable;
}


- (void)registerForKeyboardNotifications {

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selectorselector(keyboardWasShown
                                             name:UIKeyboardDidShowNotification
                                           object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selectorselector(keyboardWillBeHidden
                                             name:UIKeyboardWillHideNotification
                                           object:nil];

}

- (void)deregisterFromKeyboardNotifications {

[[NSNotificationCenter defaultCenter] removeObserver:self
                                                name:UIKeyboardDidHideNotification
                                              object:nil];

[[NSNotificationCenter defaultCenter] removeObserver:self
                                                name:UIKeyboardWillHideNotification
                                              object:nil];

}

但是当我看到 whatsapp 是如何做到的时，我的看起来就像一个黑客。 Whatsapp 的键盘与所有元素一起向上移动，而我的工作方式如下:首先显示键盘，向应用发送通知，收到通知，代码计算键盘高度并根据高度向上移动元素。

我已经搜索并找到了我实现的解决方案。

有人可以帮忙吗？

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Best Answer-推荐答案

我在我的应用程序中经常使用这个技巧。你想听 UIKeyboardWillShowNotification 和 UIKeyboardWillHideNotification。 在我看来，处理动画的最佳方式是使用自动布局。当你调用 [self.view layoutIfNeeded];您的 View 将与键盘动画一起移动。不需要动画 block 。

我设置了一个简单的 project任何人都可以尝试看看它是如何工作的!

- (void)addKeyboardNotificationsObserver {

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selectorselector(handleKeyboardWillShow name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selectorselector(handleKeyboardWillHide name:UIKeyboardWillHideNotification object:nil];

}

- (void)handleKeyboardWillShowNSNotification *)paramNotification

{

    NSDictionary* info = [paramNotification userInfo];

    //when switching languages keyboard might change its height (emoji keyboard is higher than most keyboards). 
    //You can get both sizes of the previous keyboard and the new one from info dictionary. 

    // size of the keyb that is about to disappear
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    // size of the keyb that is about to appear
    CGSize kbSizeNew = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;

    //make adjustments to constraints here...

    //and here where's magick happen!

    [self.view layoutIfNeeded];

}

- (void)handleKeyboardWillHideNSNotification *)paramNotification

{
    //adjust constraints

    [self.view layoutIfNeeded];

}

关于iOS 键盘显示事件处理，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30664160/

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