IOS File Management 2

iOS Development-file Management (ii)

V.. plist file

String method to add

NSString *path = [Nshomedirectory () stringbyappendingpathcomponent:@ "Array.plist"];

NSString *content = @ "ABCD";

[Contect Writetofile:path atomically:yes encoding:nsutf8stringencoding Error:nil];

Array mode add

NSString *path = [Nshomedirectory () stringbyappendingpathcomponent:@ "Array.plist"];

[Nsarray *array = [[Nsarray alloc] initwithobjects:@ "123", @ "798", @ "$", nil]; [Array Writetofile:path atomically:yes];

Dictionary ways to add

NSString *path = [Nshomedirectory () stringbyappendingpathcomponent:@ "Dic.plist"];                     

Nsdictionary *dic = [Nsdictionary alloc] initwithobjects:@ "First", @ "second", @ "third" forkeys:@ "123", @ "456", @ "798"]; [DiC Writetofile:path Atomically:yes];

• Arrays, dictionaries can only write bool, NSNumber, NSString, NSData, NSDate, Nsarray, nsdictionary to the attribute list plist file

Six, read the file class and common methods

• The Nsfilehandle class primarily reads and writes the contents of a file

• The Nsfilemanager class primarily operates on files (delete, modify, move, copy, and so on)

Common processing methods

+ (ID) Filehandleforreadingatpath: (NSString *) path opens a file ready to read

+ (ID) Filehandleforwritingatpath: (NSString *) path opens a file ready to write

+ (ID) Filehandleforupdatingatpath: (NSString *) path opens a file ready for update

-(NSData *) Availabledata; Returning available data from a device or channel

-(NSData *) readdatatoendoffile; Reads from the current node to the end of the file

-(NSData *) Readdataoflength: (nsuinteger) length; Reads the specified length data starting from the current node

-(void) WriteData: (NSData *) data; Write Data

-(unsigned long long) offsetinfile; Gets the offset of the current file

-(void) Seektofileoffset: (unsigned long long) offset; Jumps to the offset of the specified file

-(unsigned long long) seektoendoffile; Jump to end of file

-(void) Truncatefileatoffset: (unsigned long long) offset; Set the length of the file to offset bytes

-(void) closefile; Close File

Append data to a file

NSString *homepath = Nshomedirectory ();         

NSString *sourcepath = [HomePath stringbyappendingpathconmpone:@ "Testfile.text"];

Nsfilehandle *fielhandle = [Nsfilehandle Filehandleforupdatingatpath:sourcepath];

[FileHandle Seektoendoffile]; To jump a node to the end of a file

NSString *str = @ "Append data"

nsdata* stringdata = [str datausingencoding:nsutf8stringencoding];

[FileHandle Writedata:stringdata]; Append Write Data

[FileHandle CloseFile];

Locating data

Nsfilemanager *FM = [Nsfilemanager Defaultmanager];

NSString *content = @ "abcdef";

[FM Createfileatpath:path contents:[content datausingencoding:nsutf8stringencoding] attributes:nil];

Nsfilehandle *filehandle = [Nsfilehandle Filehandleforreadingatpath:path];

Nsuinteger length = [filehandle availabeldata] length]; Get Data length

[FileHandle SEEKTOFILEOFFSET;LENGTH/2]; Half of the offset file

NSData *data = [FileHandle readdatatoendoffile];

[FileHandle CloseFile];

Copying files

Nsfilehandle *infile, *outfile; Input file, output file

NSData *buffer; Buffered data read

Nsfilemanager *filemanager = [Nsfilemanager Defaultmanager];

NSString *homepath = Nshomedirectory ();

NSString *sourcepath = [HomePath stringbyappendingpathcomponent:@ "testfile.txt"]; Source file path

NSString *outpath = [HomePath stringbyappendingpathcomponent:@ "Outfile.txt"]; Output file path

BOOL sucess = [FileManager createfileatpath:outpath contents:nil Attributes:nil];

if (!success)

{

return N0;

}

infile = [Nsfilehandle Filehandleforreadingatpath:sourcepath]; Create read source Path file

if (infile = = nil)

{

return NO;

}

outfile = [Nsfilehandle Filehandleforreadingatpath:outpath]; Create a disease open file to output

if (outfile = = nil)

{

return NO;

}

[OutFile truncatefileatoffset:0]; Set the length of the output file to 0

Buffer = [infile readdatatoendoffile]; Reading data

[OutFile Writedata:buffer]; Write input

[InFile CloseFile]; Close write, input file

[OutFile CloseFile];

IOS File Management 2