UITextView lineSpacing 导致段落行之间的光标高度不同

问题描述

我在 UITextview 中使用 NSMutableParagraphStyle 在每行文本之间添加行空间.

I'm using NSMutableParagraphStyle in my UITextview for adding linespace between each row text.

当我在 textview 中输入内容时，光标高度是正常的.但是当我将光标位置移动到第二行(不是最后一行)的文本时，光标高度越来越大.

When I type something in textview, cursor height is normal. but when I move cursor position to text on the 2nd row (not the last row), cursor height is getting bigger.

我应该怎么做才能使每行文本中的光标高度正常?这是我目前使用的代码:

What should I do to make cursor height normal in every row of the texts? This is code I'm currently using:

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
paragraphStyle.lineSpacing = 30.;
textView.font = [UIFont fontWithName:@"Helvetica" size:16];
textView.attributedText = [[NSAttributedString alloc] initWithString:@"My Text" attributes:@{NSParagraphStyleAttributeName : paragraphStyle}];

推荐答案

我终于找到了解决我问题的方案.

Finally I found a solution that solved my problem.

可以通过继承 UITextView 的子类，然后覆盖 caretRectForPosition:position 函数来更改光标高度.例如:

Changing the cursor height is possible by subclassing the UITextView, then overriding the caretRectForPosition:position function. For example:

- (CGRect)caretRectForPosition:(UITextPosition *)position {
    CGRect originalRect = [super caretRectForPosition:position];
    originalRect.size.height = 18.0;
    return originalRect;
}

文档链接:https://developer.apple.com/documentation/uikit/uitextinput/1614518-caretrectforposition

参见内特的回答.

对于 Swift 4.x 使用 caretRect(for position: UITextPosition) ->CGRect.

For Swift 4.x use caretRect(for position: UITextPosition) -> CGRect.

import UIKit

class MyTextView: UITextView {

    override func caretRect(for position: UITextPosition) -> CGRect {
        var superRect = super.caretRect(for: position)
        guard let font = self.font else { return superRect }

        // "descender" is expressed as a negative value,
        // so to add its height you must subtract its value
        superRect.size.height = font.pointSize - font.descender
        return superRect
    }
}

文档链接:https://developer.apple.com/documentation/uikit/uitextinput/1614518-caretrect

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