Question

我正在为每次执行应用程序编写一个简单的日志文件。日志文件名基于当前时间并存储在app目录中。下面的代码是我尝试在模拟器上运行的代码，但是当我在iPad上执行时它失败并且“不允许操作”（errno.h中的EPERM）。

-(BOOL)CreateLogFile
{
    mLogFilePath = [self GetLogFileNameForTimeNow];
    BOOL Success = [[NSFileManager defaultManager] createFileAtPath:mLogFilePath contents:nil attributes:nil];

    /*BOOL Success = [[NSFileManager defaultManager] createFileAtPath:mLogFilePath contents:nil attributes:[NSDictionary dictionaryWithObject:NSFileProtectionComplete
                                                                                                                                     forKey:NSFileProtectionKey]];*/

    if ( Success )
    {
        NSLog( @"Successfully created file: %@", mLogFilePath );
        mLogFileHandle = [NSFileHandle fileHandleForWritingAtPath:mLogFilePath];
        [self WriteInstanceInformationToLog];
    }
    else
    {
        NSLog( @"Failed to create file: %@ %s", mLogFilePath, strerror(errno) );
    }

    return Success;
}

我也尝试了注释掉的代码，但也失败了。我是iOS编程的新手，所以可能会遗漏一些基本的东西。无论如何，上面的输出形式在iPad上显示如下：

2013-05-10 14:54:51.794 RichTest1[128:907] Failed to create file:
/var/mobile/Applications/XXXX/RichTest1.app/20130510145451.log Operation not permitted

但在模拟器上它可以工作：

2013-05-10 15:07:14.696 RichTest1[1604:c07] Successfully created file:
Users/abruce/Library/Application Support/iPhone Simulator/6.1/Applications/XXXX/RichTest1.app/20130510150714.log

我哪里错了？

- 编辑以下是GetLogFileNameForTimeNow

的代码

-(NSString*)GetLogFileNameForTimeNow
{
    NSString* FileName = [NSString stringWithFormat:@"%@.log", [self GetTimeAsString] ];
    NSString* AppFolderPath = [[NSBundle mainBundle] resourcePath];
    return [NSString stringWithFormat:@"%@/%@", AppFolderPath, FileName];
}

-(NSString*)GetTimeAsString
{
    return [mDateFormatter stringFromDate:[NSDate date]];
}

和日期格式化程序在我的类的构造函数中设置如下：

mDateFormatter = [[NSDateFormatter alloc] init];
NSString* DateFormat = @"yyyyMMddHHmmss";
[mDateFormatter setDateFormat:DateFormat];

Answer 1

您正在尝试在应用包内创建一个文件，该文件在设备上是只读的。将您的文件放入应用程序的Documents或Library目录中。

Answer 2

您正尝试在无权创建文件的位置创建文件

在文档文件夹

中创建文件

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"20130510150714.log"];
BOOL Success = [[NSFileManager defaultManager] createFileAtPath:filePath contents:nil attributes:nil];

Answer 3

我通过更改GetLogFileNameForTimeNow函数修复了问题，如下所示：

-(NSString*)GetLogFileNameForTimeNow
{
    NSString* FileName = [NSString stringWithFormat:@"%@.log", [self GetTimeAsString] ];

    NSArray* Paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString* DocumentsDirectory = [Paths objectAtIndex:0]; // Get documents folder
    return [NSString stringWithFormat:@"%@/%@", DocumentsDirectory, FileName];
}

NSFileManager createFileAtPath在iPad上失败但在Simulator上运行

3 个答案: