相关疑难解决方法(0)

我想在iPhone 5.1模拟器上的文档文件夹中保存数据.

 NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [NSString stringWithFormat:@"%@/%@", documentsDirectory, @"myData.json"];

if ([[NSFileManager defaultManager] isWritableFileAtPath:filePath]) {
    NSLog(@"Writable");
}else {
    NSLog(@"Not Writable");
}

我总是"不可写".任何的想法？请帮我.