iphone UITextView设置行间距

Question

如何在UITextView中增加行空间,使其在iPhone中看起来像"Notes"应用程序？

Answer 1

那么现在在iOS6上,有一种可能性,使用NSParagraphStyle,但它的记录很少,似乎很少工作.

我目前正在研究这样的事情:

UITextView *lab = [LocalTexts objectAtIndex:j];

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
paragraphStyle.lineHeightMultiple = 50.0f;
paragraphStyle.maximumLineHeight = 50.0f;
paragraphStyle.minimumLineHeight = 50.0f;

NSString *string = lab.text;
NSDictionary *ats = @{
    NSFontAttributeName: [UIFont fontWithName:@"DIN Medium" size:16.0f],
    NSParagraphStyleAttributeName: paragraphStyle, 
};

lab.attributedText = [[NSAttributedString alloc] initWithString:string attributes:ats];

问题是,当您设置字体时,行高停止工作.很奇怪.我还没有找到解决方法.

您也可以创建一个自定义的Attributed CoreText视图......但它更具技术性,你可以在这里找到它是如何完成的演示

好吧,我希望有所帮助.

Answer 2

使用Swift 4和iOS 11,根据您的需要,您可以选择以下3个实现中的一个来解决您的问题.

#1.使用String和UIFontDescriptorSymbolicTraits traitLooseLeading财产

traitLooseLeading 有以下声明:

该字体使用更宽松的前导值.

static var traitLooseLeading: UIFontDescriptorSymbolicTraits { get }

以下代码显示了如何实现traitLooseLeading以便为您的字体提供更宽松的字体UItextView.

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let textView = UITextView()
        view.addSubview(textView)

        textView.text = """
        Lorem ipsum
        Dolor sit amet,
        consectetur adipiscing elit
        """

        if let fontDescriptor = UIFontDescriptor
            .preferredFontDescriptor(withTextStyle: UIFontTextStyle.body)
            .withSymbolicTraits(UIFontDescriptorSymbolicTraits.traitLooseLeading) {
            let looseLeadingFont = UIFont(descriptor: fontDescriptor, size: 0)
            textView.font = looseLeadingFont
        }

        // Layout textView
        textView.translatesAutoresizingMaskIntoConstraints = false
        textView.topAnchor.constraint(equalTo: view.readableContentGuide.topAnchor).isActive = true
        textView.bottomAnchor.constraint(equalTo: view.readableContentGuide.bottomAnchor).isActive = true
        textView.leadingAnchor.constraint(equalTo: view.readableContentGuide.leadingAnchor).isActive = true
        textView.trailingAnchor.constraint(equalTo: view.readableContentGuide.trailingAnchor).isActive = true
    }

}

#2.使用NSAttributedString和NSMutableParagraphStyle lineSpacing财产

lineSpacing 有以下声明:

一行片段底部与下一行片段顶部之间的距离.

var lineSpacing: CGFloat { get set }

以下代码显示了如何实现lineSpacing,以便为您的某些属性文本指定特定的行间距UItextView.

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let string = """
        Lorem ipsum
        Dolor sit amet,
        consectetur adipiscing elit
        """

        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineSpacing = 15

        let attributes: [NSAttributedStringKey: Any] = [NSAttributedStringKey.paragraphStyle: paragraphStyle]
        let attributedString = NSAttributedString(string: string, attributes: attributes)

        let textView = UITextView()
        textView.attributedText = attributedString
        view.addSubview(textView)

        // Layout textView
        textView.translatesAutoresizingMaskIntoConstraints = false
        textView.topAnchor.constraint(equalTo: view.readableContentGuide.topAnchor).isActive = true
        textView.bottomAnchor.constraint(equalTo: view.readableContentGuide.bottomAnchor).isActive = true
        textView.leadingAnchor.constraint(equalTo: view.readableContentGuide.leadingAnchor).isActive = true
        textView.trailingAnchor.constraint(equalTo: view.readableContentGuide.trailingAnchor).isActive = true
    }

}

#3.使用String和NSLayoutManagerDelegate协议layoutManager(_:lineSpacingAfterGlyphAt:withProposedLineFragmentRect:)方法

layoutManager(_:lineSpacingAfterGlyphAt:withProposedLineFragmentRect:) 有以下声明:

返回以给定的字形索引结束的行之后的间距.[...]在布置每一行时发送此消息,以使布局管理器委托能够自定义行的形状.

optional func layoutManager(_ layoutManager: NSLayoutManager, lineSpacingAfterGlyphAt glyphIndex: Int, withProposedLineFragmentRect rect: CGRect) -> CGFloat

以下代码显示了如何实现layoutManager(_:lineSpacingAfterGlyphAt:withProposedLineFragmentRect:) 以便为您的特定行间距UItextView.

import UIKit

class ViewController: UIViewController, NSLayoutManagerDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        let textView = UITextView()
        textView.layoutManager.delegate = self
        view.addSubview(textView)

        textView.text = """
        Lorem ipsum
        Dolor sit amet,
        consectetur adipiscing elit
        """

        // Layout textView
        textView.translatesAutoresizingMaskIntoConstraints = false
        textView.topAnchor.constraint(equalTo: view.readableContentGuide.topAnchor).isActive = true
        textView.bottomAnchor.constraint(equalTo: view.readableContentGuide.bottomAnchor).isActive = true
        textView.leadingAnchor.constraint(equalTo: view.readableContentGuide.leadingAnchor).isActive = true
        textView.trailingAnchor.constraint(equalTo: view.readableContentGuide.trailingAnchor).isActive = true
    }

    // MARK: - NSLayoutManagerDelegate

    func layoutManager(_ layoutManager: NSLayoutManager, lineSpacingAfterGlyphAt glyphIndex: Int, withProposedLineFragmentRect rect: CGRect) -> CGFloat {
        return 15
    }

}

作为前面代码的替代,以下代码显示了如何layoutManager(_:lineSpacingAfterGlyphAt:withProposedLineFragmentRect:) 在UITextView子类中实现.

import UIKit

class LineSpacingTextView: UITextView, NSLayoutManagerDelegate {

    override init(frame: CGRect, textContainer: NSTextContainer?) {
        super.init(frame: frame, textContainer: textContainer)
        layoutManager.delegate = self
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    // MARK: - NSLayoutManagerDelegate

    func layoutManager(_ layoutManager: NSLayoutManager, lineSpacingAfterGlyphAt glyphIndex: Int, withProposedLineFragmentRect rect: CGRect) -> CGFloat {
        return 15
    }

}

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let textView = LineSpacingTextView()
        view.addSubview(textView)

        textView.text = """
        Lorem ipsum
        Dolor sit amet,
        consectetur adipiscing elit
        """

        // Layout textView
        textView.translatesAutoresizingMaskIntoConstraints = false
        textView.topAnchor.constraint(equalTo: view.readableContentGuide.topAnchor).isActive = true
        textView.bottomAnchor.constraint(equalTo: view.readableContentGuide.bottomAnchor).isActive = true
        textView.leadingAnchor.constraint(equalTo: view.readableContentGuide.leadingAnchor).isActive = true
        textView.trailingAnchor.constraint(equalTo: view.readableContentGuide.trailingAnchor).isActive = true
    }

}

Answer 3

要更改行间距:

NSString *textViewText =self.myTextView.text;

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:textViewText];
NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
paragraphStyle.lineSpacing = 30;
NSDictionary *dict = @{NSParagraphStyleAttributeName : paragraphStyle };
[attributedString addAttributes:dict range:NSMakeRange(0, [textViewText length])];

self.myTextView.attributedText = attributedString;

Answer 4

查看UITextView的文档就足以确定该控件不支持更改行间距.

适用于iOS 6及以上版本:

有可能,使用NSParagraphStyle,

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
paragraphStyle.lineHeightMultiple = 50.0f;
paragraphStyle.maximumLineHeight = 50.0f;
paragraphStyle.minimumLineHeight = 50.0f;
NSString *string = @"your paragraph here";
NSDictionary *attribute = @{
   NSParagraphStyleAttributeName : paragraphStyle, 
   };
[textview setFont:[uifont fontwithname:@"Arial" size:20.0f]];
textview.attributedText = [[NSAttributedString alloc] initWithString:string attributes:attribute];

Answer 5

对于Swift 2.2

let paragraphStyle: NSMutableParagraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineHeightMultiple = 20.0
paragraphStyle.maximumLineHeight = 20.0
paragraphStyle.minimumLineHeight = 20.0
let ats = [NSFontAttributeName: UIFont(name: "Helvetica Neue", size: 11.0)!, NSParagraphStyleAttributeName: paragraphStyle]
cell.textView.attributedText = NSAttributedString(string: "you string here", attributes: ats)