ios – 在UITextView中选择一个单词

由于在CoreText中添加了NSLayoutManager,因此iOS 7更容易实现.如果您正在处理UITextView,则可以将布局管理器作为视图的属性进行访问.在我的情况下,我想坚持使用UILabel,所以你必须创建一个大小相同的布局管理器,即：

NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:labelText];
NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
[textStorage addLayoutManager:layoutManager];
CGRect bounds = label.bounds;
NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:bounds.size];
[layoutManager addTextContainer:textContainer];

现在你只需要找到被点击的字符的索引,这很简单！

NSUInteger characterIndex = [layoutManager characterIndexForPoint:location
                                                  inTextContainer:textContainer
                         fractionOfdistanceBetweenInsertionPoints:NULL];

这使得找到这个词本身变得微不足道：

if (characterIndex < textStorage.length) {
  [labelText.string enumerateSubstringsInRange:NSMakeRange(0,textStorage.length)
                                       options:NsstringEnumerationByWords
                                    usingBlock:^(Nsstring *substring,NSRange substringRange,NSRange enclosingRange,BOOL *stop) {
                                      if (NSLocationInRange(characterIndex,enclosingRange)) {
                                        // Do your thing with the word,at range 'enclosingRange'
                                        *stop = YES;
                                      }
                                    }];
}

原始答案,适用于iOS< 7 感谢@JP Hribovsek提供了一些有关此工作的提示,我设法为我的目的解决了这个问题.它感觉有点hacky,对于大型文本可能不会很好,但对于一次一段(这是我需要的),它很好. 我创建了一个简单的UILabel子类,允许我设置插入值：

#import "WWLabel.h"

#define WWLabelDefaultInset 5

@implementation WWLabel

@synthesize topInset,leftInset,bottomInset,rightInset;

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        self.topInset = WWLabelDefaultInset;
        self.bottomInset = WWLabelDefaultInset;
        self.rightInset = WWLabelDefaultInset;
        self.leftInset = WWLabelDefaultInset;
    }
    return self;
}

- (void)drawTextInRect:(CGRect)rect
{
    UIEdgeInsets insets = {self.topInset,self.leftInset,self.bottomInset,self.rightInset};

    return [super drawTextInRect:UIEdgeInsetsInsetRect(rect,insets)];
}

然后我创建了一个包含我的自定义标签的UIView子类,然后在标签上构建了标签中每个单词的文本大小,直到大小超过了点击位置的大小 – 这是被点击的单词.这不是完美的,但现在效果还不错.

然后我使用一个简单的NSAttributedString来突出显示文本：

#import "WWPhoneticTextView.h"
#import "WWLabel.h"

#define WWPhoneticTextViewInset 5
#define WWPhoneticTextViewDefaultColor [UIColor blackColor]
#define WWPhoneticTextViewHighlightColor [UIColor yellowColor]

#define UILabelMagicTopMargin 5
#define UILabelMagicLeftMargin -5

@implementation WWPhoneticTextView {
    WWLabel *label;
    NSMutableAttributedString *labelText;
    NSRange tappedRange;
}

// ... skipped init methods,very simple,just call through to configureView

- (void)configureView
{
    if(!label) {
        tappedRange.location = NSNotFound;
        tappedRange.length = 0;

        label = [[WWLabel alloc] initWithFrame:[self bounds]];
        [label setLineBreakMode:NSLineBreakByWordWrapping];
        [label setNumberOfLines:0];
        [label setBackgroundColor:[UIColor clearColor]];
        [label setTopInset:WWPhoneticTextViewInset];
        [label setLeftInset:WWPhoneticTextViewInset];
        [label setBottomInset:WWPhoneticTextViewInset];
        [label setRightInset:WWPhoneticTextViewInset];

        [self addSubview:label];
    }


    // Setup tap handling
    UITapGestureRecognizer *singleFingerTap = [[UITapGestureRecognizer alloc]
                                               initWithTarget:self action:@selector(handleSingleTap:)];
    singleFingerTap.numberOfTapsrequired = 1;
    [self addGestureRecognizer:singleFingerTap];
}

- (void)setText:(Nsstring *)text
{
    labelText = [[NSMutableAttributedString alloc] initWithString:text];
    [label setAttributedText:labelText];
}

- (void)handleSingleTap:(UITapGestureRecognizer *)sender
{
    if (sender.state == UIGestureRecognizerStateEnded)
    {
        // Get the location of the tap,and normalise for the text view (no margins)
        CGPoint tapPoint = [sender locationInView:sender.view];
        tapPoint.x = tapPoint.x - WWPhoneticTextViewInset - UILabelMagicLeftMargin;
        tapPoint.y = tapPoint.y - WWPhoneticTextViewInset - UILabelMagicTopMargin;

        // Iterate over each word,and check if the word contains the tap point in the correct line
        __block Nsstring *partialString = @"";
        __block Nsstring *linestring = @"";
        __block int currentLineHeight = label.font.pointSize;
        [label.text enumerateSubstringsInRange:NSMakeRange(0,[label.text length]) options:NsstringEnumerationByWords usingBlock:^(Nsstring* word,NSRange wordRange,BOOL* stop){

            CGSize sizeforText = CGSizeMake(label.frame.size.width-2*WWPhoneticTextViewInset,label.frame.size.height-2*WWPhoneticTextViewInset);
            partialString = [Nsstring stringWithFormat:@"%@ %@",partialString,word];

            // Find the size of the partial string,and stop if we've hit the word
            CGSize partialStringSize  = [partialString sizeWithFont:label.font constrainedToSize:sizeforText lineBreakMode:label.lineBreakMode];

            if (partialStringSize.height > currentLineHeight) {
                // Text wrapped to new line
                currentLineHeight = partialStringSize.height;
                linestring = @"";
            }
            linestring = [Nsstring stringWithFormat:@"%@ %@",linestring,word];

            CGSize linestringSize  = [linestring sizeWithFont:label.font constrainedToSize:label.frame.size lineBreakMode:label.lineBreakMode];
            linestringSize.width = linestringSize.width + WWPhoneticTextViewInset;

            if (tapPoint.x < linestringSize.width && tapPoint.y > (partialStringSize.height-label.font.pointSize) && tapPoint.y < partialStringSize.height) {
                NSLog(@"Tapped word %@",word);
                if (tappedRange.location != NSNotFound) {
                    [labelText addAttribute:NSForegroundColorAttributeName value:[UIColor blackColor] range:tappedRange];
                }

                tappedRange = wordRange;
                [labelText addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:tappedRange];
                [label setAttributedText:labelText];
                *stop = YES;
            }
        }];        
    }
}