在iOS7或TextKit中使用什么而不是scrollRangeToVisible

问题描述

在以前版本的iOS中，我的 UITextView 将使用

In previous versions of iOS, my UITextView will scroll to the bottom using

[displayText scrollRangeToVisible:NSMakeRange(0,[displayText.text length])];

或

CGFloat topCorrect = displayText.contentSize.height -[displayText bounds].size.height;
topCorrect = (topCorrect<0.0?0.0:topCorrect);
displayText.contentOffset = (CGPoint){.x=0, .y=topCorrect};

但前者现在会产生奇怪的效果，从长篇文本的顶部开始，每次我将文本追加到视图时，动画滚动到底部。当我添加文字时，有没有办法弹出文本的底部？

But the former will now have the weird effect of starting at the top of a long length of text and animating the scroll to the bottom each time I append text to the view. Is there a way to pop down to the bottom of the text when I add text?

推荐答案

对于未来的旅行者，建立的@ mikeho的帖子，我发现了一些对我有用的东西，但有点简单。

For future travelers, building off of @mikeho's post, I found something that worked wonders for me, but is a bit simpler.

1）确保你的 UITextView 的 contentInset 已正确设置&在执行此操作之前，你的textView已经是 firstResponder（）。

2）在我的插件准备就绪后，光标处于活动状态时，我调用以下函数：

1) Be sure your UITextView's contentInsets are properly set & your textView is already firstResponder() before doing this.
2) After my the insets are ready to go, and the cursor is active, I call the following function:

private func scrollToCursorPosition() {
    let caret = textView.caretRectForPosition(textView.selectedTextRange!.start)
    let keyboardTopBorder = textView.bounds.size.height - keyboardHeight!

   // Remember, the y-scale starts in the upper-left hand corner at "0", then gets
   // larger as you go down the screen from top-to-bottom. Therefore, the caret.origin.y
   // being larger than keyboardTopBorder indicates that the caret sits below the
   // keyboardTopBorder, and the textView needs to scroll to the position.
   if caret.origin.y > keyboardTopBorder {
        textView.scrollRectToVisible(caret, animated: true)
    }
 }

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