IOS File Management 2 and ios File Management

IOS File Management 2 and ios File Management
IOS development-File Management (2)

5. Plist files

Add in String Mode

NSString * path = [NSHomeDirectory () stringByAppendingPathComponent: @ "Array. plist"];

NSString * content = @ "abcd ";

[Contect writeToFile: path atomically: YES encoding: NSUTF8StringEncoding error: nil];

Array

NSString * path = [NSHomeDirectory () stringByAppendingPathComponent: @ "Array. plist"];

[NSArray * array = [[NSArray alloc] initWithObjects: @ "123", @ "798", @ "000", nil]; [array writeToFile: path atomically: YES];

Add in Dictionary Mode

NSString * path = [NSHomeDirectory () stringByAppendingPathComponent: @ "Dic. plist"];

NSDictionary * dic = [NSDictionary alloc] initWithObjects: @ "first", @ "second", @ "third" forKeys: @ "123", @ "456 ", @ "798"]; [dic writeToFile: path atomically: YES];

• Arrays and dictionaries can only write BOOL, NSNumber, NSString, NSData, NSDate, NSArray, and NSDictionary to plist files in the property list.

6. Reading files and common methods

• The NSFileHandle class mainly reads and writes the file content.

• NSFileManager class is mainly used for file operations (delete, modify, move, copy, and so on)

Common Handling Methods

+ (Id) fileHandleForReadingAtPath :( NSString *) path open a file to prepare for reading

+ (Id) fileHandleForWritingAtPath :( NSString *) path to open a file to prepare for writing

+ (Id) fileHandleForUpdatingAtPath :( NSString *) path to open a file and prepare for update

-(NSData *) availableData; returns available data from the device or channel

-(NSData *) readDataToEndOfFile; read from the current node to the end of the file

-(NSData *) readDataOfLength :( NSUInteger) length; read the specified length data from the current node

-(Void) writeData :( NSData *) data; write data

-(Unsigned long) offsetInFile; get the offset of the current file

-(Void) seekToFileOffset :( unsigned long) offset; jump to the offset of the specified file

-(Unsigned long) seekToEndOfFile; jump to the end of the file

-(Void) truncateFileAtOffset :( unsigned long) offset; set the object length to offset bytes.

-(Void) closeFile; close the file

Append data to a file

NSString * homePath = NSHomeDirectory ();

NSString * sourcePath = [homePath stringByAppendingPathConmpone: @ "testfile. text"];

NSFileHandle * fielHandle = [NSFileHandle fileHandleForUpdatingAtPath: sourcePath];

[FileHandle seekToEndOfFile]; jump the node to the end of the file

NSString * str = @ "append data"

NSData * stringData = [str dataUsingEncoding: NSUTF8StringEncoding];

[FileHandle writeData: stringData]; append and write data

[FileHandle closeFile];

Locate data

NSFileManager * fm = [NSFileManager defamanager manager];

NSString * content = @ "abcdef ";

[Fm createFileAtPath: path contents: [content dataUsingEncoding: NSUTF8StringEncoding] attributes: nil];

NSFileHandle * fileHandle = [NSFileHandle fileHandleForReadingAtPath: path];

NSUInteger length = [fileHandle availabelData] length]; get the Data length

[FileHandle seekToFileOffset; length/2]; half of the Offset File

NSData * data = [fileHandle readDataToEndOfFile];

[FileHandle closeFile];

Copy a file

NSFileHandle * infile, * outfile; input file and output file

NSData * buffer; read buffer data

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 a file to read The Source Path

If (infile = nil)

{

Return NO;

}

Outfile = [NSFileHandle fileHandleForReadingAtPath: outPath]; create a disease to open the file to be output

If (outfile = nil)

{

Return NO;

}

[Outfile truncateFileAtOffset: 0]; set the length of the output file to 0

Buffer = [infile readDataToEndOfFile]; read data

[Outfile writeData: buffer]; write Input

[Infile closeFile]; close writing and input files

[Outfile closeFile];