学步园

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 Tipsnhttp://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];



5、获得文件的属性
-(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: %qin", [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);
   }
}
 
 
 
 
//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];
 


6、读取文件内容操作
- (void) loadFileContentsIntoTextView
{
//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];
}