UILabel erkennt Zeilenumbrüche

Question

Ich verwende derzeit eine UILabel, um mehrere Textzeilen anzuzeigen. Der Zeilenumbruch am meisten wird auf NSLineBreakByWordWrapping gesetzt, so dass das Label Zeilenumbrüche automatisch einfügt. Wie kann ich erkennen, wo diese Zeilenumbrüche liegen? Grundsätzlich möchte ich einen String mit jeweils \n Pause zurückgeben.

Answer 1

Hier ist meine Arbeit um zur Erkennung Linie UILabel

- (int)getLengthForString:(NSString *)str fromFrame:(CGRect)frame withFont:(UIFont *)font 
{ 
    int length = 1; 
    int lastSpace = 1; 
    NSString *cutText = [str substringToIndex:length]; 
    CGSize textSize = [cutText sizeWithFont:font constrainedToSize:CGSizeMake(frame.size.width, frame.size.height + 500)]; 
    while (textSize.height <= frame.size.height) 
    { 
     NSRange range = NSMakeRange (length, 1); 
     if ([[str substringWithRange:range] isEqualToString:@" "]) 
     { 
      lastSpace = length; 
     } 
     length++; 
     cutText = [str substringToIndex:length]; 
     textSize = [cutText sizeWithFont:font constrainedToSize:CGSizeMake(frame.size.width, frame.size.height + 500)]; 
    } 
    return lastSpace; 
} 


-(NSString*) getLinebreaksWithString:(NSString*)labelText forWidth:(CGFloat)lblWidth forPoint:(CGPoint)point 
{ 
    //Create Label 
    UILabel *label = [[UILabel alloc] init]; 
    label.text = labelText; 
    label.numberOfLines = 0; 
    label.lineBreakMode = NSLineBreakByWordWrapping; 

    //Set frame according to string 
    CGSize size = [label.text sizeWithFont:label.font 
         constrainedToSize:CGSizeMake(lblWidth, MAXFLOAT) 
          lineBreakMode:UILineBreakModeWordWrap]; 
    [label setFrame:CGRectMake(point.x , point.y , size.width , size.height)]; 

    //Add Label in current view 
    [self.view addSubview:label]; 

    //Count the total number of lines for the Label which has NSLineBreakByWordWrapping line break mode 
    int numLines = (int)(label.frame.size.height/label.font.leading); 

    //Getting and dumping lines from text set on the Label 
    NSMutableArray *allLines = [[NSMutableArray alloc] init]; 

    BOOL shouldLoop = YES; 
    while (shouldLoop) 
    { 
     //Getting length of the string from rect with font 
     int length = [self getLengthForString:labelText fromFrame:CGRectMake(point.x, point.y, size.width, size.height/numLines) withFont:label.font] + 1;   

     [allLines addObject:[labelText substringToIndex:length]]; 

     labelText = [labelText substringFromIndex:length]; 
     if(labelText.length<length) 
      shouldLoop = NO; 
    } 

    [allLines addObject:labelText]; 
    //NSLog(@"\n\n%@\n",allLines); 

    return [allLines componentsJoinedByString:@"\n"]; 
} 

innen bricht Wie

NSString *labelText = @"We are what our thoughts have made us; so take care about what you think. Words are secondary. Thoughts live; they travel far."; 

NSString *stringWithLineBreakChar = [self getLinebreaksWithString:labelText forWidth:200 forPoint:CGPointMake(15, 15)]; 
NSLog(@"\n\n%@",stringWithLineBreakChar); 

Sie nur Parameter von getLinebreaksWithString erforderlich einstellen müssen und Sie werden Holen Sie sich eine Zeichenfolge mit jedem "\ n" Pause enthalten.

OutPut

Answer 2

Hier ist meine Lösung für dieses Problem.
Ich durchlaufe alle Leerzeichen in der angegebenen Zeichenfolge, setze Teilstrings (vom Anfang bis zum aktuellen Leerzeichen) auf meine Beschriftung und überprüfe den Unterschied in der Höhe. Wenn sich die Höhe ändert, füge ich ein neues Zeilenzeichen ein (simuliert einen Zeilenumbruch).

func wordWrapFormattedStringFor(string: String) -> String { 
    // Save label state 
    let labelHidden = label.isHidden 
    let labelText = label.text 

    // Set text to current label and size it to fit the content 
    label.isHidden = true 
    label.text = string 
    label.sizeToFit() 
    label.layoutIfNeeded() 

    // Prepare array with indexes of all whitespace characters 
    let whitespaceIndexes: [String.Index] = { 
     let whitespacesSet = CharacterSet.whitespacesAndNewlines 
     var indexes: [String.Index] = [] 

     string.unicodeScalars.enumerated().forEach { i, unicodeScalar in 
      if whitespacesSet.contains(unicodeScalar) { 
       let index = string.index(string.startIndex, offsetBy: i) 
       indexes.append(index) 
      } 
     } 

     // We want also the index after the last character so that when we make substrings later we include also the last word 
     // This index can only be used for substring to this index (not from or including, since it points to \0) 
     let index = string.index(string.startIndex, offsetBy: string.characters.count) 
     indexes.append(index) 

     return indexes 
    }() 

    var reformattedString = "" 

    let boundingSize = CGSize(width: label.bounds.width, height: CGFloat.greatestFiniteMagnitude) 
    let attributes = [NSFontAttributeName: font] 

    var runningHeight: CGFloat? 
    var previousIndex: String.Index? 

    whitespaceIndexes.forEach { index in 
     let string = string.substring(to: index) 
     let stringHeight = string.boundingRect(with: boundingSize, options: .usesLineFragmentOrigin, attributes: attributes, context: nil).height 

     var newString: String = { 
      if let previousIndex = previousIndex { 
       return string.substring(from: previousIndex) 
      } else { 
       return string 
      } 
     }() 

     if runningHeight == nil { 
      runningHeight = stringHeight 
     } 

     if runningHeight! < stringHeight { 
      // Check that we can create a new index with offset of 1 and that newString does not contain only a whitespace (for example if there are multiple consecutive whitespaces) 
      if newString.characters.count > 1 { 
       let splitIndex = newString.index(newString.startIndex, offsetBy: 1) 
       // Insert a new line between the whitespace and rest of the string 
       newString.insert("\n", at: splitIndex) 
      } 
     } 

     reformattedString += newString 

     runningHeight = stringHeight 
     previousIndex = index 
    } 

    // Restore label 
    label.text = labelText 
    label.isHidden = labelHidden 

    return reformattedString 
} 

Image - Comparison of output string with label text.

Diese Lösung wirklich gut in meinem Fall gearbeitet, hoffe, es hilft.