ios - xCode 不允许添加对象

Question

这里绝对是新手。我正在尝试使用几种不同的来源自学 Xcode。在我当前的类(class)中，我只是试图将字符串中的每个单词大写。出于某种原因，我没有使用 addObject 的选项，即使我已经求助于逐行复制书中的内容!这是我正在使用的代码，我只是将其输入到 ViewController.m 中。我没有接触过头文件。

#import "ViewController.h"
@interface ViewController ()

@end
@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.


    NSString *myString = @"How much wood could a woodchuck chuck";

    NSArray *wordsInSentence = [myString componentsSeparatedByString:@" "];
    NSLog(@"%@", wordsInSentence);

    NSMutableArray *capitalizedWords = [[NSMutableArray alloc] init];

    for (int word =0; word < [wordsInSentence count]; word++)
    {

        NSString *uncapitalizedWords = [wordsInSentence objectAtIndex:word];
        NSString *capitalizedWords = [uncapitalizedWords capitalizedString];
        [capitalizedWords addObject:capitalizedWords];
    }
    NSLog(@"%@", capitalizedWords);
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

我的问题是 [大写词 addObject:大写词]; 当我开始输入时，它甚至没有在下拉框中显示 addObject 作为选项，我唯一的选项是 addObserver。

非常感谢任何帮助，谢谢

Answer 1

问题是您有两个具有相同名称的变量，capitalizedWords。一个是可变数组，另一个是字符串。因此，当您在 for 循环中使用 capitalizedWords 时，它使用的是字符串再现。我建议重命名字符串变量，例如，替换:

NSString *uncapitalizedWords = [wordsInSentence objectAtIndex:word];
NSString *capitalizedWords = [uncapitalizedWords capitalizedString];
[capitalizedWords addObject:capitalizedWords];

与

NSString *uncapitalizedWord = [wordsInSentence objectAtIndex:word];  // renaming this isn't critical, but using singular case makes it more clear
NSString *capitalizedWord = [uncapitalizedWord capitalizedString];   // renaming this fixes the problem
[capitalizedWords addObject:capitalizedWord];