为什么 NSMutableDictionary 不想写入文件？
- (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 - 我创建一个 NSMutableDictionary 并将其写入路径中的文件，但 writeToFile 方法返回 NO。问题出在哪里？如果我使用 NSFileManager 创建此文件，它可以工作，但当我想编写字典时却不能。
- (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);
}
}
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.
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writeToFile:atomically仅当您调用它的字典是有效的属性列表对象时才有效（参见文档）。要使 NSDictionary 成为有效的属性列表对象，除其他外，其 键必须是字符串，但在您的示例中，键是
NSNumber实例。writeToFile:atomicallyonly works if the dictionary you call it on is a valid property list object (see docs).For a
NSDictionaryto be a valid property list object, among other things, its keys must be strings, but in your example the keys areNSNumberinstances.有时你无法控制要写的内容。例如，当您要编写从服务器获取的 JSON 对象时，您无法避免使用
null值。NSData与这些“无效”值兼容，因此将NSArray或NSDictionary转换为NSData是一种理想的方式这些案例。写：
读：
You can not control the content you are going to write sometimes. For example, you can't avoid a
nullvalue when you are going to write a JSON object that is gotten from a server.NSDatais compatible with these "invalid" values, so convertingNSArrayorNSDictionarytoNSDatais an ideal way in these cases.write:
read: