iOS鍵盤顯示事件處理

Question

我正在使用一個聊天應用程序，其中有一個textview（不是textfield），當我單擊它時，鍵盤應該會顯示並且一切都應該向上移動。

到現在為止，我已經設法向上移動表格視圖和textview的框架，並使用以下代碼顯示鍵盤。

- (void)keyboardWasShown:(NSNotification *)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)keyboardWillBeHidden:(NSNotification *)notification {

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


- (void)registerForKeyboardNotifications {

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardWasShown:)
                                             name:UIKeyboardDidShowNotification
                                           object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(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，當我看到whatsapp的工作方式時，我的樣子就像是黑客。 Whatsapp的鍵盤與所有元素一起向上移動，而我的工作方式如下：首先顯示鍵盤，將通知發送到應用程序，接收到通知，代碼計算鍵盤的高度，然后根據高度向上移動元素。

我搜索並找到了已實施的解決方案。

有人可以幫忙嗎？

Answer 1

我在應用程序中經常使用此技巧。 您想聽UIKeyboardWillShowNotification和UIKeyboardWillHideNotification 。 我認為處理動畫的最佳方法是使用自動布局。 當您調用[self.view layoutIfNeeded]時； 您的視圖將隨鍵盤動畫一起移動。 不需要動畫塊。

我已經建立了一個簡單的項目 ，任何人都可以嘗試看看它是如何工作的！

- (void)addKeyboardNotificationsObserver {

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

}

- (void)handleKeyboardWillShow:(NSNotification *)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)handleKeyboardWillHide:(NSNotification *)paramNotification

{
    //adjust constraints

    [self.view layoutIfNeeded];

}

Answer 2

1. 您可以使用UIKeyboardWillShowNotification和UIKeyboardWillHideNotification
2. 從這里嘗試TPKeyboardAvoidingScrollView： https : //github.com/michaeltyson/TPKeyboardAvoiding （我的選擇）