IOS中NSFileManager的操作 [Z]

1、文件的创建

 

-(IBAction) CreateFile { //对于错误信息 NSError *error; // 创建文件管理器 NSFileManager *fileMgr = [NSFileManager defaultManager]; //指向文件目录 NSString *documentsDirectory= [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]; //创建一个目录 [[NSFileManager defaultManager]   createDirectoryAtPath: [NSString stringWithFormat:@"%@/myFolder", NSHomeDirectory()] attributes:nil]; // File we want to create in the documents directory我们想要创建的文件将会出现在文件目录中 // Result is: /Documents/file1.txt结果为：/Documents/file1.txt NSString *filePath= [documentsDirectory stringByAppendingPathComponent:@"file2.txt"]; //需要写入的字符串 NSString *str= @"iPhoneDeveloper Tips\nhttp://iPhoneDevelopTips,com"; //写入文件 [str writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:&error]; //显示文件目录的内容 NSLog(@"Documentsdirectory:  contentsOfDirectoryAtPath:documentsDirectory error:&error]); }

 

 

2、对文件重命名

 

对一个文件重命名 想要重命名一个文件，我们需要把文件移到一个新的路径下。下面的代码创建了我们所期望的目标文件的路径，然后请求移动文件以及在移动之后显示文件目录。 //通过移动该文件对文件重命名 NSString *filePath2= [documentsDirectory stringByAppendingPathComponent:@"file2.txt"]; //判断是否移动 if ([fileMgr moveItemAtPath:filePath toPath:filePath2 error:&error] != YES) NSLog(@"Unable to move file: %@", [error localizedDescription]); //显示文件目录的内容 NSLog(@"Documentsdirectory: %@", [fileMgr contentsOfDirectoryAtPath:documentsDirectoryerror:&error]);

 

 

3、删除一个文件

 

为了使这个技巧完整，让我们再一起看下如何删除一个文件： //在filePath2中判断是否删除这个文件 if ([fileMgr removeItemAtPath:filePath2 error:&error] != YES) NSLog(@"Unable to delete file: %@", [error localizedDescription]); //显示文件目录的内容 NSLog(@"Documentsdirectory: %@", [fileMgr contentsOfDirectoryAtPath:documentsDirectoryerror:&error]); 一旦文件被删除了，正如你所预料的那样，文件目录就会被自动清空： 这些示例能教你的，仅仅只是文件处理上的一些皮毛。想要获得更全面、详细的讲解，你就需要掌握NSFileManager文件的知识。

 

 

4、删除目录下所有文件

 

//获取文件路径 - (NSString *)attchmentFolder{ NSString *document = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; NSString *path = [document stringByAppendingPathComponent:@"Attchments"]; NSFileManager *manager = [NSFileManager defaultManager]; if(![manager contentsOfDirectoryAtPath:path error:nil]){ [manager createDirectoryAtPath:path withIntermediateDirectories:NO attributes:nil error:nil]; } return path; }   --清除附件 BOOL result = [[NSFileManager defaultManager] removeItemAtPath:[[MOPAppDelegate instance] attchmentFolder] error:nil];

IPhone中获取文件各项属性方法

-(NSData *)applicationDataFromFile:(NSString *)fileName
{
    NSArray *paths =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
    NSString *documentsDirectory =[paths objectAtIndex:0];
    NSString *appFile =[documentsDirectory stringByAppendingPathComponent:fileName];
    NSData *data =[[[NSData alloc]initWithContentsOfFile:appFile]autorelease];
    return data;
}

-(void)getFileAttributes
{
NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *path = @"/1ct.rtf";
NSDictionary *fileAttributes = [fileManager fileAttributesAtPath:path traverseLink:YES];
    NSLog(@"@@");
if (fileAttributes != nil) {
    NSNumber *fileSize;
    NSString *fileOwner, *creationDate;
    NSDate *fileModDate;
    //NSString *NSFileCreationDate

//文件大小
    if (fileSize = [fileAttributes objectForKey:NSFileSize]) {
        NSLog(@"File size: %qi\n", [fileSize unsignedLongLongValue]);
    }

//文件创建日期
    if (creationDate = [fileAttributes objectForKey:NSFileCreationDate]) {
        NSLog(@"File creationDate: %@\n", creationDate);
        //textField.text=NSFileCreationDate;
    }

//文件所有者
    if (fileOwner = [fileAttributes objectForKey:NSFileOwnerAccountName]) {
        NSLog(@"Owner: %@\n", fileOwner);
    }

//文件修改日期
    if (fileModDate = [fileAttributes objectForKey:NSFileModificationDate]) {
        NSLog(@"Modification date: %@\n", fileModDate);
    }
 }
else {
    NSLog(@"Path (%@) is invalid.", path);
   }
}

 

 

///////////////////

文件类型，文件缩略图呢？？？

 

============================

//获取当前应用程序的主目录
NSString directoryPath =NSHomeDirectory();

//获取当前目录下的所有文件
NSArray directoryContents = [[NSFileManager defaultManager] directoryContentsAtPath: directoryPath];

 

//获取一个文件或文件夹
NSString *selectedFile = (NSString*)[directoryContents objectAtIndex: indexPath.row];

//拼成一个完整路径
[directoryPath stringByAppendingPathComponent: selectedFile];

 

 

BOOL isDir;

//判断是否是为目录

if ([[NSFileManager defaultManager] fileExistsAtPath:selectedPath isDirectory:&isDir] && isDir)

{//目录
}

else

{//文件
}

 

 

 

 

//日期格式化
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter setDateStyle:NSDateFormatterMediumStyle];

[dateFormatter setTimeStyle:NSDateFormatterNoStyle];

//数字格式化

NSNumberFormatter *numberFormatter =[[NSNumberFormatter alloc] init];

[numberFormatter setPositiveFormat: @"#,##0.## bytes"];

 

 

//获取文件属性

NSDictionary *fileAttributes =[[NSFileManager defaultManager] fileAttributesAtPath: directoryPath traverseLink: YES];

//获取文件的创建日期

NSDate *modificationDate = (NSDate*)[fileAttributes objectForKey: NSFileModificationDate];

//获取文件的字节大小

NSNumber *fileSize = (NSNumber*)[fileAttributes objectForKey: NSFileSize];
//格式化文件大小
nsstring A = [numberFormatter stringFromNumber: fileSize];

//格式化文件创建日期

NSstring B =[dateFormatter stringFromDate: modificationDate];

 

[numberFormatter release];

[dateFormatter release];

 

//读取文件内容操作

- (void) loadFileContentsIntoText View

{

 

 

//通过流打开一个文件

 

NSInputStream *inputStream = [[NSInputStream alloc] initWithFileAtPath: filePath];

 

[inputStream open];

 

NSInteger maxLength = 128;

uint8_t readBuffer [maxLength];

//是否已经到结尾标识

BOOL endOfStreamReached = NO;

// NOTE: this tight loop will block until stream ends

while (! endOfStreamReached)

{

NSInteger bytesRead = [inputStream read: readBuffer maxLength:maxLength];

if (bytesRead == 0)

{//文件读取到最后

endOfStreamReached = YES;

}

else if (bytesRead == -1)

{//文件读取错误

endOfStreamReached = YES;

}

else

{

NSString *readBufferString =[[NSString alloc] initWithBytesNoCopy: readBuffer length: bytesRead encoding: NSUTF8StringEncoding freeWhenDone: NO];   

//将字符不段的加载到视图

[self appendTextToView: readBufferString];

[readBufferString release];

}

}

[inputStream close];

[inputStream release];

}

 

 

 

 

异步文件读取  在网络方面，网络的不可靠性可能会造成上面方法的阻塞

nsstream是可以异步工作的。可以注册一个在流中有字节可读的时候回调的函数，如果没有可读的，就不要阻塞住