Question

我正在编写一个文本编辑器应用程序，我试图将NSString作为NSData存储在documents文件夹中的文件中，例如我希望能够存储文件“myText.java”。

我的代码在模拟器上工作。但是，在设备上似乎创建了一个文件，但是当我稍后尝试从文件中加载数据时，我什么也得不到。

我是否必须设置一些项目设置以启用设备上的文档目录或我的代码是否错误？

这是我的商店代码：

-(void) saveFile:(NSString*)file{
    if (![file isEqual:@"Empty"]) {
        NSArray *paths = NSSearchPathForDirectoriesInDomains
        (NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString *fullFilePath = [documentsDirectory stringByAppendingPathComponent:file];

        [[NSFileManager defaultManager] removeItemAtPath: fullFilePath error: nil];
        NSLog(@"File: %@", fullFilePath); 
        //Above LOGS: /var/mobile/Applications/2310F459-282C-4488-AE24-D5795168F85A/Documents/fg

        //save content to the documents directory
        NSLog(@"Saving: %@", codeView.text);
        // Logs the data i want to store
        [[codeView.text dataUsingEncoding:NSASCIIStringEncoding] writeToFile:fullFilePath atomically:YES];
    }
}

这是我的加载文件代码：

-(void) loadFile:(NSString*)filename{
    NSArray *paths = NSSearchPathForDirectoriesInDomains
    (NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    //make a file name to write the data to using the documents directory:
    NSString *file = [documentsDirectory stringByAppendingPathComponent:filename];
    if ([[NSFileManager defaultManager] fileExistsAtPath:file]) {
        NSLog(@"File found");
        //Yes the file is found

        theDelegate.fileData = [NSData dataWithContentsOfFile:file];
        NSLog(@"Data:%@",[[NSString alloc] initWithData:[NSData dataWithContentsOfFile:file] encoding:NSASCIIStringEncoding]);
        // On device and simulator data is found

        [theDelegate.codeView setText:[[NSString alloc] initWithData:theDelegate.fileData encoding:NSASCIIStringEncoding]];
        //codeView does not get updated with the data.
        //NSLog([[NSString alloc] initWithData:theDelegate.fileData encoding:NSASCIIStringEncoding]);
        [theDelegate setTitle:filename];
        [theDelegate setHasOpenFile:YES];
        [theDelegate.codeView setEditable:theDelegate.hasOpenFile];
        [theDelegate.codeView setNeedsDisplay];
        [self setLanguage:filename];
    }else{

        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"File error!" message:@"An error occured when trying to load the selected file." delegate:self cancelButtonTitle:@"OK!" otherButtonTitles:nil, nil];
       [alert show];
    }
}

Answer 1

不，您不必启用设置即可使用文档目录。您的代码可能存在错误，也可能没有错误，无论如何都难以阅读而且不是很干净（对此说道歉。）

尝试只做一次。我冒昧地重写你的代码，以清理它。然后我在手机上使用示例应用程序对其进行了测试，它运行良好。

代码重写：

-(void) saveFile:(NSString*)filename{
    if (![filename isEqual:@"Empty"]) {

        NSString *fullFilePath = [self getFullFilePath:filename];

        [[NSFileManager defaultManager] removeItemAtPath: fullFilePath error: nil];
        NSLog(@"File: %@", fullFilePath);

        //save content to the documents directory
        NSLog(@"Saving: %@", self.codeView.text);
        // Logs the data i want to store
        [[self.codeView.text dataUsingEncoding:NSASCIIStringEncoding] writeToFile:fullFilePath atomically:YES];
    }
}

添加辅助函数后，上面的代码很好。

-(void) loadFile:(NSString*)filename{

    NSString *fullFilePath = [self getFullFilePath:filename];

    if ([[NSFileManager defaultManager] fileExistsAtPath:fullFilePath]) {
        NSLog(@"File found");
        //Yes the file is found

        NSLog(@"Data:%@",[[NSString alloc] initWithData:[NSData dataWithContentsOfFile:fullFilePath] encoding:NSASCIIStringEncoding]);
        // On device and simulator data is found

        [theDelegate.codeView setText:[[NSString alloc] initWithData:[NSData dataWithContentsOfFile:fullFilePath] encoding:NSASCIIStringEncoding]];

        [theDelegate setTitle:filename];
        [theDelegate setHasOpenFile:YES];
        [theDelegate.codeView setEditable:theDelegate.hasOpenFile];
        [theDelegate.codeView setNeedsDisplay];
        //[self setLanguage:filename];
    }else{

        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"File error!" message:@"An error occured when trying to load the selected file." delegate:self cancelButtonTitle:@"OK!" otherButtonTitles:nil, nil];
        [alert show];
    }
}

在您的旧代码中，theDelegate.fileData = [NSData dataWithContentsOfFile:file];可能存在问题，如果引用较弱。因为我假设你总是在codeView中有代码，所以似乎没有必要先将它存储在一个成员变量中。此外，这可能会导致更多错误。

以下是一个辅助函数，因此您不会在两个函数中执行完全相同的操作，因为它可能会导致错误。

-(NSString*) getFullFilePath:(NSString*)filename {
    NSArray *paths = NSSearchPathForDirectoriesInDomains
    (NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *fullFilePath = [documentsDirectory stringByAppendingPathComponent:filename];

    return fullFilePath;

}

Answer 2

您是否注意传递给loadFile:和saveFile:的文件名完全相同，包括大小写？ Mac OS X（以及扩展名为iOS模拟器）使用不区分大小写的文件名，而iOS区分大小写，并将SomeFile.txt和somefile.txt视为两种不同的东西。

在应用程序文档文件夹中存储和获取文档

2 个答案: