iOS Learning File Manager (Nsfilemanager) and file Locator (Nsfilehandle)

1. File Manager (Nsfilemanager)1> Creating a folder

Create the declaration of the desired method in the header file:

/* createDirectoryAtPath:withIntermediateDirectories:attributes:error:creates a Directory at the specified path. If you pass the "NO" for Createintermediates, the directory must not exist at the time the "This" is made. Passing ' YES ' for ' createintermediates ' would create any necessary intermediate directories. This method returns YES if any directories specified in ' path ' were created and attributes were set. Directories is created with attributes specified by the dictionary passed to ' attributes '. If No dictionary is supplied, directories was created according to the umask of the process. This method returns NO if a failure occurs on any stage of the operation.     If An error parameter is provided, a presentable nserror would be returned by reference. This method replaces createdirectoryatpath:attributes: */
Parameter 1: path to the created folder
Parameter 2: Whether to create a Boolean value for the media, generally yes
parameter 3: attribute, not set to nil
parameter 4: Error message-(BOOL) Createdirectoryatpath: (NSString *) path withintermediatedirectories: (BOOL) createintermediates attributes: ( Nullable nsdictionary<nsstring *,ID> *) Attributes Error: (NSERROR * *) Error ns_available (10_5, 2_0);

Instance code:

    //Creating ObjectsNsfilemanager *manager =[Nsfilemanager Defaultmanager]; //Create PathNSString *path =nshomedirectory (); Path= [path stringbyappendingpathcomponent:@"Test/myapp"]; NSLog (@"%@", path); Nserror*error =Nil; //Create a folderBOOL success =[Manager Createdirectoryatpath:path Withintermediatedirectories:yes Attributes:nil Error:&ERROR]; NSLog (@"success =%d,error =%@", Success,error);

2> Adding files to a folder

The content -writing method is declared in the header file:

// parameter 1: File path of the file to write to // parameter 2: A bool value, usually yes // Parameter 3: Encoding method, generally UTF8 // Parameter 4: Error message -(BOOL) WriteToFile: (NSString *) path atomically: (BOOL) useauxiliaryfile encoding: (nsstringencoding ) Enc Error: (NSERROR * *) error;

Instance code:

    //to add a string to a folderPath = [path stringbyappendingpathcomponent:@"Zifucuan.txt"]; //Initializes a stringNSString *string=@"Hello"; BOOL Success1= [stringwritetofile:path atomically:yes encoding:nsutf8stringencoding Error:nil]; if(SUCCESS1) {NSLog (@"success:%@", path); }Else{NSLog (@"failed"); }

3> deleting files in a folder

Delete File method in header file declaration:

// parameter 1: path // Parameter 2: Error message -(BOOL) removeItemAtPath: (NSString *) path error: (Nserror *) Error ns_available (10_5, 2_0);

Instance code:

    // Delete all Files    under the path directory [Manager Removeitematpath:path Error:nil];

4> File Movement

　　file Move method in header file declaration:

// parameter 1: path of the file to be moved // Parameter 2: path to the file to be moved (destination) // Parameter 3: Error message -(BOOL) Moveitematpath: (NSString *) Srcpath Topath: (NSString *) Dstpath Error: (NSERROR *) Error Ns_ AVAILABLE (10_5, 2_0);

Instance code:

NSString *documentpath = [Nssearchpathfordirectoriesindomains (nsdocumentdirectory, NSUserDomainMask, YES) Objectatindex:0]; //Create a folderNSString *copypath = [Documentpath stringbyappendingpathcomponent:@"Backup/test.txt"]; //stringbydeletinglastpathcomponent Delete the last path[manager Createdirectoryatpath:[copypath Stringbydeletinglastpathcomponent] Withintermediatedirectories:yes    Attributes:nil Error:nil]; //Define a stringNSString *teststr =@"Hello World"; NSData*data =[Teststr datausingencoding:nsutf8stringencoding]; //writing content to a file[manager Createfileatpath:copypath Contents:data Attributes:nil]; //Create a TopathNSString *topath = [Documentpath stringbyappendingpathcomponent:@"Hello/copytest.txt"]; //Create a folder and file to move to[manager Createdirectoryatpath:[topath Stringbydeletinglastpathcomponent] Withintermediatedirectories:yes        Attributes:nil Error:nil]; BOOL result=[Manager Moveitematpath:copypath Topath:topath E    Rror:nil]; NSLog (@"result =%d", result);

5> file copy (copy)

The file copy (copy) method is declared in the header file:

//
parameter 2: to copy
Parameter 3: Error message
-(BOOL) Copyitematpath: (NSString *) Srcpath Topath: (NSString *) Dstpath Error: (NSERROR *) Error ns_available (10_5, 2_0);

Instance code:

// path using the path above [manager Copyitematpath:copypath                     Topath:topath                      Error:nil];

2. Folder Processor (Nsfilehandle)1> using Nsfilehandle to append content to a folder

• Update via FileHandle

// The parameter is file path + (nullable instancetype) Filehandleforupdatingatpath: (NSString *) path;

• Search to end of text content method

// Search to end of file content Long long) Seektoendoffile;

• Instance code: (using the path above)

 //  Create handle object  Nsfilehandle *        FileHandle = [Nsfilehandle Filehandleforupdatingatpath:path];  //  Search to the end of text content   [FileHandle Seektoendoffile]; NSString  *appendstr = @ "  I was later . Span style= "color: #800000;"        > " ;        NSData  *appenddata = [Appendstr datausingencoding:nsutf8stringencoding];  //  writes data to the docking   [FileHandle Writedata:appenddata];  //  close docking  [FileHandle closefile]; 

2> Locating data

• Read through FileHandle

parameter is file path
+ (Nullable Instancetype) Filehandleforreadingatpath: (NSString *) path;

• Get data available in a file (all data)

@property (readonly, copy) NSData *availabledata;

• Set the offset of a file

// parameter is a numeric value associated with the length of the file -(voidlonglong) offset;

• Read from the offset position of the file to the last

-(NSData *) readdatatoendoffile;

Instance code:

    //write "123456" to the File2.txt folderNSString * content =@"123456"; NSString* FilePath2 = [Documentpath stringbyappendingpathcomponent:@"File2.txt"];        [FileManager createfileatpath:filepath2 contents:[content datausingencoding:nsutf8stringencoding] attributes:nil]; //Read through FileHandleFileHandle =[Nsfilehandle filehandleforreadingatpath:filepath2]; //Get Data lengthNsuinteger length =[[FileHandle availabledata] length]; //set the file offset to half of the file[FileHandle seektofileoffset:length/2.0]; //read from the offset position of the file to the lastNSData * data =[FileHandle Readdatatoendoffile];    [FileHandle CloseFile]; //print a read stringNSString *string=[[NSString alloc] Initwithdata:data encoding:nsutf8stringencoding]; NSLog (@"%@",string);

iOS Learning File Manager (Nsfilemanager) and file Locator (Nsfilehandle)