Xcode 不创建文件

Question

我正在编写一个将文本保存到 CSV 文件的应用程序。但是在模拟器中试了之后找不到路径下的文件。

代码如下：

    #import "protboViewController.h"

@interface protboViewController ()

@end

@implementation protboViewController
@synthesize email;

- (IBAction)retractKeyboard:(id)sender{
    [self resignFirstResponder];
}
- (IBAction)saveInfo:(id)sender {
    NSString *resultLine=[NSString stringWithFormat:@"%@\n",
                          self.email.text];

    NSString *docPath =[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)objectAtIndex:0];

    NSString *mailLista=[docPath stringByAppendingPathComponent:@"elista.csv"];

                          if  (![[NSFileManager defaultManager] fileExistsAtPath:docPath]) {
                              [[NSFileManager defaultManager] createFileAtPath:mailLista contents:nil attributes:nil];
                          }
                          NSFileHandle *fileHandle = [NSFileHandle fileHandleForUpdatingAtPath:mailLista];
                          [fileHandle seekToEndOfFile];
                          [fileHandle writeData:[resultLine dataUsingEncoding:NSUTF8StringEncoding]];
                          [fileHandle closeFile];
                            self.email.text=@"";
                          NSLog(@"info saved");
}

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

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

@end

我在控制台中收到“信息已保存”提示，但是当我转到“iPhone Simulator”文件夹并检查没有文件时。

另外，我如何从设备将此文件导出到我的计算机？

提前致谢！

编辑：

现在我让它创建一个文件并添加一行文本，但如果我尝试添加一行文本，整个文件将被替换为带有一行文本的新文件。

#import "protboViewController.h"

@interface protboViewController ()

@end

@implementation protboViewController
@synthesize email;


- (IBAction)retractKeyboard:(id)sender{
    [self resignFirstResponder];
}
- (IBAction)saveInfo:(id)sender {
    NSString *resultLine=[NSString stringWithFormat:@"%@\n",
                          self.email.text];

    NSArray *docPath =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    NSString *docDirectory = [docPath objectAtIndex:0];

    NSString *mailLista=[docDirectory stringByAppendingPathComponent:@"elista.csv"];

    NSError *csvError = NULL;

    BOOL written = [resultLine writeToFile:mailLista atomically:YES encoding:NSUTF8StringEncoding error:&csvError];

    if (!written)
        NSLog(@"write failed, error=%@", csvError);
    else
        NSLog(@"Saved! File path =", mailLista);

}

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

}

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

@end

我搜索了一个答案，发现“由于您没有使用 for 循环，请确保并在您的头文件中声明 outputString。在您的 viewDidLoad 中对其进行初始化，然后您将能够附加到它。”

如何在我的头文件中声明它，我应该在 viewDidLoad 中初始化什么？

再次感谢。

Answer 1

将此添加到您的“protboViewController.h”

@property (nonatomic, strong) NSString* mailLista;

将此添加到您的 viewDidLoad：

NSString *docPath =[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)objectAtIndex:0];
self.mailLista = [docPath stringByAppendingPathComponent:@"elista.csv"];
if  (![[NSFileManager defaultManager] fileExistsAtPath:docPath]) {
    [[NSFileManager defaultManager] createFileAtPath:self.mailLista contents:nil attributes:nil];
}

最后把你的 saveInfo 改成这样：

NSString *resultLine=[NSString stringWithFormat:@"%@\n", self.email.text];

NSFileHandle *fileHandle = [NSFileHandle fileHandleForWritingAtPath:self.mailLista];
[fileHandle seekToEndOfFile];
[fileHandle writeData:[resultLine dataUsingEncoding:NSUTF8StringEncoding]];
[fileHandle closeFile];
self.email.text=@"";

NSLog(@"Saved! File path =%@", self.mailLista);

这就是我之前在我自己的一个应用中所做的方式