Archiving (serialization), anti-archiving (deserialization) of iOS file operations and custom objects

iOS file operations include the creation of files, read-write, move, delete, and so on.

1. Creation of files:

Set the location where the text box stores the file    nsstring *strfilepath=[nssearchpathfordirectoriesindomains (nsdocumentdirectory, Nsuserdomainmask, YES) objectatindex:0];//Specify the file name of the store    nsstring *filename=[strfilepath stringbyappendingpathcomponent:@ "test.txt"];//File Manager <pre name= "code" class= "OBJC" >nsfilemanager *fmaneger=[ Nsfilemanager Defaultmanager];    if ([Fmaneger fileexistsatpath:[self GetFilePath]]) {        self.txtfield.text=[nsstring stringwithcontentsoffile:[ Self GetFilePath] encoding:nsutf8stringencoding Error:nil];    }

2. Writing the file

Write text content    [self.txtField.text writetofile:filename atomically:yes encoding:nsutf8stringencoding Error:nil];    NSLog (@ "Save succeeded");

3. Read the file

Nsfilemanager *fmanager=[nsfilemanager Defaultmanager];    if ([Fmanager fileexistsatpath:filename]) {                [Fmanager createfileatpath:filename contents:nil attributes:nil];    }

4. Movement of files

    Move file    //destination folder    nsstring *destpath=nstemporarydirectory ();    Destination file path    NSString * Destfilepath=[destpath stringbyappendingpathcomponent:@ "test.txt"];        BOOL Result=[fmanager Moveitematpath:filepath Topath:destfilepath Error:nil];    if (result) {        NSLog (@ "move succeeded");    }    else    {        NSLog (@ "Move failed!");    }

5. Deletion of files

Nsfilemanager *fmanager=[nsfilemanager Defaultmanager]; [Fmanager Removeitematpath:filepath Error:nil];

File Operation Summary:

The operation of the file requires the path of the file to be specified before the

Nssearchpathfordirectoriesindomains

To find the file path.

When a file path is obtained or specified, a Nsfilemanager object is required for the creation, movement, and so on of the file.

There are many ways to write a file, basically there are nsstring,nsdictionary, and Nsarray and its subclasses can call the Write method to write the data to the file.

The following is a demonstration of file write and read for the object of the custom class (i.e., archive/reverse archive):

Steps:

1. Define a person class and have the person class implement the Nscoding protocol ( the Protocol must be implemented to implement the archive )

  person.h//  file Operations////  Created by Lifewahaha on 15/5/15.//  Copyright (c) 2015 Lifewahaha. All rights reserved.//#import <Foundation/Foundation.h> @interface person:nsobject<nscoding> @property ( strong,nonatomic) NSString *name; @property (nonatomic) int age;-initwithname: (NSString *) name; @end

2. Implement two Protocol methods in the implementation file of the person class

-(void) Encodewithcoder: (Nscoder *) Acoder

-(ID) Initwithcoder: (Nscoder *) Adecoder

  person.m//  file Operations////  Created by Lifewahaha on 15/5/15.//  Copyright (c) 2015 Lifewahaha. All rights reserved.//#import "Person.h" @implementation person-(ID) initwithname: (NSString *) name{    if ([Super Init ]) {        self.name=name;    }    return self;} #pragma-mark method to convert an object to NSData-(void) Encodewithcoder: (Nscoder *) acoder{    [Acoder encodeObject:self.name forkey:@] Name "];    [Acoder encodeInt:self.age forkey:@ "Age"];} -(ID) Initwithcoder: (Nscoder *) adecoder{    if ([self init]) {        //decompression process        self.name= [Adecoder decodeobjectforkey:@ "name"];        Self.age=[adecoder decodeintforkey:@ "Age"];    }    return self;    } @end

3. In Viewcontroller, import the header file of the person class, and then implement the following method in Viewdidload

-(void) viewdidload {[Super viewdidload];    Person *p=[[person Alloc]init];    [email protected] "a";    p.age=12;    Archive, serialize ****************//1. Create a mutable binary stream nsmutabledata *data=[[nsmutabledata alloc]init]; 2. Create an Archive object (with the ability to convert a custom class into a binary stream) Nskeyedarchiver *archiver=[[nskeyedarchiver alloc]initforwritingwithmutabledata:    Data];    3. Using the Archive object, convert the object of the custom class into a binary stream [archiver encodeobject:p forkey:@ "person"];        4 archive Complete [archiver finishencoding];       Write data to file [data writetofile:[self Getobjfilepath] atomically:yes];        NSLog (@ "%@", data); Anti-archive ****************** nsmutabledata *mdata=[nsmutabledata datawithcontentsoffile:[self    Getobjfilepath]]; 2. Create an anti-archive object that nskeyedunarchiver the binary data into a positive row of OC data *unarchiver=[[nskeyedunarchiver Alloc]initforreadingwithdata:    Mdata];        Person *p2= [unarchiver decodeobjectforkey:@ ' person ']; NSLog (@ "Name:%@", p2.name);

}

Archiving (serialization), anti-archiving (deserialization) of iOS file operations and custom objects