UITableViewCell 中的 UITextView 平滑自动调整大小显示和隐藏 iPad 上的键盘，但适用于 iPhone [英] UITextView in a UITableViewCell smooth auto-resize shows and hides keyboard on iPad, but works on iPhone

问题描述

我已经实现了一个自定义 UITableViewCell，其中包括一个 UITextView，它会根据用户类型自动调整大小，类似于联系人应用程序中的备注"字段.它在我的 iPhone 上工作正常，但是当我在 iPad 上测试它时，我得到了一些非常奇怪的行为:当你到达一行的末尾时，键盘会隐藏一毫秒，然后立即再次显示出来.我会把它写成一个古怪的错误，但它实际上会导致一些数据丢失，因为如果你在打字，它会丢失一两个字符.这是我的代码:

I have implemented a custom UITableViewCell which includes a UITextView that auto-resizes as the user types, similar to the "Notes" field in the Contacts app. It is working properly on my iPhone, but when I am testing it in the iPad, I am getting some very strange behavior: When you get to the end of a line, the keyboard hides for a millisecond and then shows itself again immediately. I would write it off as just a quirky bug, but it actually causes some data loss since if you are typing, it loses a character or two. Here's my code:

// returns the proper height/size for the UITextView based on the string it contains.
// If no string, it assumes a space so that it will always have one line.
- (CGSize)textViewSize:(UITextView*)textView {
     float fudgeFactor = 16.0;
     CGSize tallerSize = CGSizeMake(textView.frame.size.width-fudgeFactor, kMaxFieldHeight);
     NSString *testString = @" ";
     if ([textView.text length] > 0) {
          testString = textView.text;
     }
     CGSize stringSize = [testString sizeWithFont:textView.font constrainedToSize:tallerSize lineBreakMode:UILineBreakModeWordWrap];
     return stringSize;
}

// based on the proper text view size, sets the UITextView's frame
- (void) setTextViewSize:(UITextView*)textView {
     CGSize stringSize = [self textViewSize:textView];
     if (stringSize.height != textView.frame.size.height) {
          [textView setFrame:CGRectMake(textView.frame.origin.x,
                                        textView.frame.origin.y,
                                        textView.frame.size.width,
                                        stringSize.height+10)];  // +10 to allow for the space above the text itself 
     }
}

// as per: https://stackoverflow.com/questions/3749746/uitextview-in-a-uitableviewcell-smooth-auto-resize
- (void)textViewDidChange:(UITextView *)textView {

     [self setTextViewSize:textView]; // set proper text view size
     UIView *contentView = textView.superview;
     // (1) the padding above and below the UITextView should each be 6px, so UITextView's
     // height + 12 should equal the height of the UITableViewCell
     // (2) if they are not equal, then update the height of the UITableViewCell
     if ((textView.frame.size.height + 12.0f) != contentView.frame.size.height) {
         [myTableView beginUpdates];
         [myTableView endUpdates];

         [contentView setFrame:CGRectMake(0,
                                          0,
                                          contentView.frame.size.width,
                                          (textView.frame.size.height+12.0f))];
     }
}

- (CGFloat)tableView:(UITableView  *)tableView heightForRowAtIndexPath:(NSIndexPath  *)indexPath {
     int height;
     UITextView *textView = myTextView;
     [self setTextViewSize:textView];
     height = textView.frame.size.height + 12;
     if (height < 44) { // minimum height of 44
          height = 44;
          [textView setFrame:CGRectMake(textView.frame.origin.x,
                                        textView.frame.origin.y,
                                        textView.frame.size.width,
                                        44-12)];
      }
      return (CGFloat)height;
}

问题

所以，这就是正在发生的事情

The Problems

So, here's what's happening

1. 此代码在我的 iPhone 和 iPhone 模拟器上 100% 正常运行.当我输入文本时，UITextView 平滑增长，UITableViewCell 随之增长.
2. 然而，在 iPad 模拟器上，它变得很棘手.当您在第一行打字时它工作正常，但是当您到达一行的末尾时，键盘会消失然后立即重新出现，因此如果用户继续输入应用程序会错过一两个字符.
3. 这里有一些关于我注意到的奇怪行为的附加说明，可能有助于解释它:
   • 另外，我发现删除行 [myTableView beginUpdates];[myTableView endUpdates]; 函数中的 textViewDidChange:(UITextView *)textView 使 UITextView 正常增长并且也没有显示和隐藏键盘，但不幸的是，然后 UITableViewCell 没有t 长到合适的高度.
   • 更新:关注这些说明，我现在可以停止文字的奇怪移动；但是键盘还在隐藏和显示，这很奇怪.

1. This code is working 100% properly on my iPhone and in the iPhone simulator. As I type the text, the UITextView grows smoothly, and the UITableViewCell along with it.
2. On the iPad simulator, however, it gets screwy. It works fine while you are typing on the first line, but when you get to the end of a line, the keyboard disappears and then reappears immediately, so that if the user continues typing the app misses a character or two.
3. Here are some additional notes on the weird behaviors that I have noticed which may help explain it:
   • Also, I have found that removing the lines [myTableView beginUpdates]; [myTableView endUpdates]; in the function textViewDidChange:(UITextView *)textView makes the UITextView grow properly and also doesn't show and hide the keyboard, but unfortunately, then the UITableViewCell doesn't grow to the proper height.
   • UPDATE: Following these instructions, I am now able to stop the strange movement of the text; but the keyboard is still hiding and showing, which is very strange.

有没有人知道如何让键盘持续显示，而不是在 iPad 行尾时隐藏和显示?

PS:我对使用 ThreeTwenty 不感兴趣.

P.S.: I am not interested in using ThreeTwenty.

推荐答案

you should return NO in:

you should return NO in:

 -(BOOL) textViewShouldEndEditing:(UITextView *)textView

如果您想一直显示键盘.您应该通过向此委托函数返回 YES 来处理应该隐藏哪个键盘的情况.

if you would like to show keyboard at all times. You should handle cases, which keyboard should be hidden, by returning YES to this delegate function.

我挖了一点，当 [tableView endUpdates] 调用时，它基本上做了 3 件事:

I dug a little more, when [tableView endUpdates] called, it basically does 3 things :

1. 禁用 tableView
上的用户交互
2. 更新单元格更改
3. 在 tableView 上启用用户交互

1. Disables user interaction on the tableView
2. Updates cell changes
3. Enables user interaction on the tableView

SDK(平台)之间的区别在于[UIView setUserInteractionEnabled] 方法.由于 UITableView 不会覆盖 setUserInteractionEnabled 方法，它是从 super (UIView) 调用的.

The difference between SDKs(platforms) is at [UIView setUserInteractionEnabled] method. As UITableView does not overrite setUserInteractionEnabled method, it is called from super (UIView).

iPhone 在 setUserInteractionEnabled 调用时，会寻找一个私有字段 _shouldResignFirstResponderWithInteractionDisabled，默认返回 NO，因此不会让第一响应者退出>(UITextView)

iPhone when setUserInteractionEnabled called, looks for a private field _shouldResignFirstResponderWithInteractionDisabled which returns NO as default, so does not resign the first responder (UITextView)

但在 iPad 上没有这样的检查 AFAIK，因此它在 步骤 1 上退出 UITextView，并设置焦点并使其成为 步骤 3<的第一响应者/强>

But on iPad there is no such check AFAIK, so it resignes UITextView on step 1, and sets focus and makes it first responder on step 3

基本上，根据 SDK 文档，textViewShouldEndEditing 可以让您保持专注，是您唯一的选择 ATM.

Basically, textViewShouldEndEditing, which allows you to keep focus, according to SDK docs, is your only option ATM.

当文本出现时调用此方法视图被要求先辞职响应者状态.这可能会发生当用户试图改变编辑焦点到另一个控件.在焦点真正改变之前，然而，文本视图调用这个给你的代表一个机会的方法决定是否应该这样做.

This method is called when the text view is asked to resign the first responder status. This might occur when the user tries to change the editing focus to another control. Before the focus actually changes, however, the text view calls this method to give your delegate a chance to decide whether it should.

这篇关于UITableViewCell 中的 UITextView 平滑自动调整大小显示和隐藏 iPad 上的键盘，但适用于 iPhone的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！