Objective-c 每 23 个字符换行而不断字

Question

我从这篇帖子Objective-c Line breaks every 10 characters (Keeping words in tact) 中找到了这个算法，问题是它永远不会返回最后一个单词，它总是以某种方式丢弃它。

NSString *sourceStr = @"The Chocholate Experience in the Anna Ice Cream Museum - Spanish";

NSMutableString *resultString = [[NSMutableString alloc] init];
NSMutableString *currentLine = [[NSMutableString alloc] init];
NSMutableArray *stringsArray = [[NSMutableArray alloc] init];
NSScanner *scanner = [NSScanner scannerWithString:sourceStr];
NSString *scannedString = nil;

while ([scanner scanUpToCharactersFromSet:[NSCharacterSet whitespaceCharacterSet] intoString: &scannedString]) {
    if ([currentLine length] + [scannedString length] <= 23) {
        [currentLine appendFormat:@"%@ ", scannedString];
    }
    else if ([currentLine length] == 0) { // Newline but next word > 23
        [resultString appendFormat:@"%@\n", scannedString];
    }
    else { // Need to break line and start new one
        [resultString appendFormat:@"%@\n", currentLine];
        [currentLine setString:[NSString stringWithFormat:@"%@ ", scannedString]];
    }
    [scanner scanCharactersFromSet:[NSCharacterSet whitespaceCharacterSet] intoString:NULL];
}
NSLog(@"Result String: \n%@", resultString);

I get this as the output: 
The Chocholate 
Experience in the Anna 
Ice Cream Museum -

去掉最后一个单词是西班牙语。任何人都可以看到错误？我已经在这几个小时了。任何帮助将不胜感激

Answer 1

如果您单步执行，您会注意到，当您在 while 循环之外时，您缺少的单词存储在 currentLine 变量中。基本上，最后一个 else 条件将“Ice Cream Museum -”附加到 resultString，但因为没有其他要扫描的内容（“Spanish”已保存在已扫描字符串中 - 所以它已经被扫描），它只是将当前行中的单词“Spanish”，并且不会通过 while 循环的另一次迭代（因此永远不会将它放在要打印的 resultString 中）。

这是应该打印出最后一个单词的修改后的代码：

NSString *sourceStr = @"The Chocholate Experience in the Anna Ice Cream Museum - Spanish";

NSMutableString *resultString = [[NSMutableString alloc] init];
NSMutableString *currentLine = [[NSMutableString alloc] init];
NSMutableArray *stringsArray = [[NSMutableArray alloc] init];
NSScanner *scanner = [NSScanner scannerWithString:sourceStr];
NSString *scannedString = nil;

while ([scanner scanUpToCharactersFromSet:[NSCharacterSet whitespaceCharacterSet] intoString: &scannedString]) {

    // keep appending as long as we have something to append to
    if ([currentLine length] + [scannedString length] <= 23) {
        [currentLine appendFormat:@"%@ ", scannedString];
    }
    else if ([currentLine length] == 0) { // Newline but next word > 23
        [resultString appendFormat:@"%@\n", scannedString];
    }
    else { // Need to break line and start new one
        [resultString appendFormat:@"%@\n", currentLine];
        [currentLine setString:[NSString stringWithFormat:@"%@ ", scannedString]];
    }
    [scanner scanCharactersFromSet:[NSCharacterSet whitespaceCharacterSet] intoString:NULL];
}
// we may have something left over that couldn't fit into the last line
// that needs to be appended to the result string
if (currentLine.length > 0) {
    [resultString appendFormat:@"%@\n", currentLine];
}
NSLog(@"Result String: \n%@", resultString);