IOS中NSFileManager的操作 [Z]

1、檔案的建立

 

-(IBAction) CreateFile { //對於錯誤資訊 NSError *error; // 建立檔案管理工具 NSFileManager *fileMgr = [NSFileManager defaultManager]; //指向檔案目錄 NSString *documentsDirectory= [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]; //建立一個目錄 [[NSFileManager defaultManager]   createDirectoryAtPath: [NSString stringWithFormat:@"%@/myFolder", NSHomeDirectory()] attributes:nil]; // File we want to create in the documents directory我們想要建立的檔案將會出現在檔案目錄中 // Result is: /Documents/file1.txt結果為：/Documents/file1.txt NSString *filePath= [documentsDirectory stringByAppendingPathComponent:@"file2.txt"]; //需要寫入的字串 NSString *str= @"iPhoneDeveloper Tips\nhttp://iPhoneDevelopTips,com"; //寫入檔案 [str writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:&error]; //顯示檔案目錄的內容 NSLog(@"Documentsdirectory:  contentsOfDirectoryAtPath:documentsDirectory error:&error]); }

 

 

2、對檔案重新命名

 

對一個檔案重新命名 想要重新命名一個檔案，我們需要把檔案移到一個新的路徑下。下面的代碼建立了我們所期望的目標檔案的路徑，然後請求移動檔案以及在移動之後顯示檔案目錄。 //通過移動該檔案對檔案重新命名 NSString *filePath2= [documentsDirectory stringByAppendingPathComponent:@"file2.txt"]; //判斷是否移動 if ([fileMgr moveItemAtPath:filePath toPath:filePath2 error:&error] != YES) NSLog(@"Unable to move file: %@", [error localizedDescription]); //顯示檔案目錄的內容 NSLog(@"Documentsdirectory: %@", [fileMgr contentsOfDirectoryAtPath:documentsDirectoryerror:&error]);

 

 

3、刪除一個檔案

 

為了使這個技巧完整，讓我們再一起看下如何刪除一個檔案： //在filePath2中判斷是否刪除這個檔案 if ([fileMgr removeItemAtPath:filePath2 error:&error] != YES) NSLog(@"Unable to delete file: %@", [error localizedDescription]); //顯示檔案目錄的內容 NSLog(@"Documentsdirectory: %@", [fileMgr contentsOfDirectoryAtPath:documentsDirectoryerror:&error]); 一旦檔案被刪除了，正如你所預料的那樣，檔案目錄就會被自動清空： 這些樣本能教你的，僅僅只是檔案處理上的一些皮毛。想要獲得更全面、詳細的講解，你就需要掌握NSFileManager檔案的知識。

 

 

4、刪除目錄下所有檔案

 

//擷取檔案路徑 - (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中擷取檔案各項屬性方法

-(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

//檔案大小

    if (fileSize = [fileAttributes objectForKey:NSFileSize]) {

        NSLog(@"File size: %qi\n", [fileSize unsignedLongLongValue]);

    }

//檔案建立日期

    if (creationDate = [fileAttributes objectForKey:NSFileCreationDate]) {

        NSLog(@"File creationDate: %@\n", creationDate);

        //textField.text=NSFileCreationDate;

    }

//檔案所有者

    if (fileOwner = [fileAttributes objectForKey:NSFileOwnerAccountName]) {

        NSLog(@"Owner: %@\n", fileOwner);

    }

//檔案修改日期

    if (fileModDate = [fileAttributes objectForKey:NSFileModificationDate]) {

        NSLog(@"Modification date: %@\n", fileModDate);

    }

 }

else {

    NSLog(@"Path (%@) is invalid.", path);

   }

}

 

 

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

檔案類型，檔案縮圖呢？？？

 

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

//擷取當前應用程式的主目錄
NSString directoryPath =NSHomeDirectory();

//擷取目前的目錄下的所有檔案
NSArray directoryContents = [[NSFileManager defaultManager] directoryContentsAtPath: directoryPath];

 

//擷取一個檔案或檔案夾
NSString *selectedFile = (NSString*)[directoryContents objectAtIndex: indexPath.row];

//拼成一個完整路徑
[directoryPath stringByAppendingPathComponent: selectedFile];

 

 

BOOL isDir;

//判斷是否是為目錄

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

{//目錄

}

else

{//檔案

}

 

 

 

 

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

[dateFormatter setDateStyle:NSDateFormatterMediumStyle];

[dateFormatter setTimeStyle:NSDateFormatterNoStyle];

//數字格式化

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

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

 

 

//擷取檔案屬性

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

//擷取檔案的建立日期

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

//擷取檔案的位元組大小

NSNumber *fileSize = (NSNumber*)[fileAttributes objectForKey: NSFileSize];
//格式檔案大小
nsstring A = [numberFormatter stringFromNumber: fileSize];

//格式檔案建立日期

NSstring B =[dateFormatter stringFromDate: modificationDate];

 

[numberFormatter release];

[dateFormatter release];

 

//讀取檔案內容操作- (void) loadFileContentsIntoTextView

{

 

 

//通過流開啟一個檔案

 

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

 

[inputStream open];

 

NSInteger maxLength = 128;

uint8_t readBuffer [maxLength];

//是否已經到結尾標識

BOOL endOfStreamReached = NO;

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

while (! endOfStreamReached)

{

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

if (bytesRead == 0)

{//檔案讀取到最後

endOfStreamReached = YES;

}

else if (bytesRead == -1)

{//檔案讀取錯誤

endOfStreamReached = YES;

}

else

{

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

//將字元不段的載入到視圖

[self appendTextToView: readBufferString];

[readBufferString release];

}

}

[inputStream close];

[inputStream release];

}

 

 

 

 

非同步檔案讀取  在網路方面，網路的不可靠性可能會造成上面方法的阻塞

nsstream是可以非同步工作的。可以註冊一個在流中有位元組可讀的時候回調的函數，如果沒有可讀的，就不要阻塞住