为什么NSMutableDictionary不想写入文件？ [英] Why NSMutableDictionary don't want write to file?

问题描述

- (void)viewDidLoad
{
    [super viewDidLoad];
    if ([[NSFileManager defaultManager] fileExistsAtPath:pathString]) 
    {
        infoDict = [[NSMutableDictionary alloc] initWithContentsOfFile:pathString];
    } 
    else 
    {
        infoDict = [[NSMutableDictionary alloc]initWithObjects:[NSArray arrayWithObjects:@"BeginFrame",@"EndFrame", nil] forKeys:[NSArray arrayWithObjects:[NSNumber numberWithBool:YES],[NSNumber numberWithBool:YES], nil]];
        if ([infoDict writeToFile:pathString atomically:YES])
        {
            NSLog(@"Created");
        } 
        else 
        {
            NSLog(@"Is not created");
            NSLog(@"Path %@",pathString);
        }
}

这是我的代码。我检查文件是否已创建 - 如果没有 - 我创建 NSMutableDictionary 并将其写入路径中的文件，但是 writeToFile 方法返回否。哪里有问题？如果我使用 NSFileManager 创建此文件，它可以工作，但是当我想写一个字典时，它不会。

This is my code. I check if file is created, if not - I create a NSMutableDictionary and I write it to file at path, but writeToFile method returns NO. Where is problem? If I create this file with NSFileManager it works, but doesn't when I want to write a dictionary.

推荐答案

writeToFile：atomically 仅在您调用它的字典是有效的属性列表对象时才有效（查看文档）。

writeToFile:atomically only works if the dictionary you call it on is a valid property list object (see docs).

要使 NSDictionary 成为有效的属性列表对象，其中包括键必须是字符串，但在您的示例中，键是 NSNumber 实例。

For a NSDictionary to be a valid property list object, among other things, its keys must be strings, but in your example the keys are NSNumber instances.

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