iOS Development-Data Persistence (i) "Text file + binary archive"

Overview

Data persistence is divided into different ways, this chapter mainly briefly shows the data archiving (generally speaking serialization) and the way of writing XML text file. The XML text mode mainly uses the Nsarray or Nsdictionary WriteToFile method, and the data archiving uses the data archiving (serialization) such as Nskeyedarchiver/nskeyedunarchiver.

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Program Display

Data file

Note the new version of the iOS emulator directory is not in the same place as the previous directory, where the plist file is an XML file that can be opened for direct viewing, while Archi is an archived binary file.

Process Overview

1. New project, drag the interface, complete the program in addition to the operation of the archive, the specific operation: slightly

2. For XML storage, place the data that needs to be stored in a dictionary or array, and then call WriteToFile to save the data to a file, using the class method initwithcontentsoffile reading the stored data can be

3. The relatively complex point of data archiving requires a new data class that implements the the Nscoding protocol then implements the encoding and decoding of two methods.

4. Place the required data in the object of the data class in step 3 where data storage is required, and then use Nsmutabledata and nskeyedarchiver for data archiving.

5. Slightly

Main codeData Classesh file

  staff.h//  dataxmlarchiver////  Created by God Lin on 14/12/9.//  Copyright (c) 2014 Arbboter. All rights reserved.//#import <Foundation/Foundation.h> @interface staff:nsobject <nscoding>{    nsstring* _nickname;    nsstring* _email;    nsstring* _phone;    nsstring* _sex;    nsstring* _position;} @property (nonatomic, retain) nsstring* _nickname; @property (nonatomic, retain) nsstring* _email; @property (Nonatomic, Retain) nsstring* _phone; @property (nonatomic, retain) nsstring* _sex; @property (nonatomic, retain) nsstring* _position; @end

m file

////staff.m//dataxmlarchiver////Created by God Lin on 14/12/9.//Copyright (c) 2014 Arbboter. All rights reserved.//#import "Staff.h" @implementation staff@synthesize _nickname; @synthesize _email; @synthesize _ phone; @synthesize _sex; @synthesize _position; #pragma nscoding implementation Serialization (archive)-(void) Encodewithcoder: (Nscoder *) acoder{[    Acoder encodeobject:self._nickname forkey:@ "nickname"];    [Acoder encodeobject:self._email forkey:@ "email"];    [Acoder encodeobject:self._phone forkey:@ "Phone"];    [Acoder encodeobject:self._sex forkey:@ "Sex"]; [Acoder encodeobject:self._position forkey:@ "position"];}    -(ID) Initwithcoder: (Nscoder *) adecoder{self._nickname = [Adecoder decodeobjectforkey:@ "nickname"];    Self._email = [Adecoder decodeobjectforkey:@ "email"];    Self._phone = [Adecoder decodeobjectforkey:@ "Phone"];    Self._sex = [Adecoder decodeobjectforkey:@ "sex"];    Self._position = [Adecoder decodeobjectforkey:@ "position"]; return self;} @end 

Program Body Codeh file

  viewcontroller.h//  dataxmlarchiver////  Created by God Lin on 14/12/9.//  Copyright (c) 2014 Arbboter. All rights reserved.//#import <UIKit/UIKit.h> @interface viewcontroller:uiviewcontroller{    iboutlet uitextfield* _textnickname;    Iboutlet uitextfield* _textemail;    Iboutlet uitextfield* _textphone;    Iboutlet uitextfield* _textsex;    Iboutlet uitextfield* _textposition;} @property (nonatomic, retain) uitextfield* _textnickname; @property (nonatomic, retain) uitextfield* _textemail;@ Property (Nonatomic, retain) uitextfield* _textphone; @property (nonatomic, retain) uitextfield* _textsex; @property ( Nonatomic, retain) uitextfield* _textposition;-(ibaction) Onhidekeyboard: (ID) sender;-(ibaction) Onxmlsave: (ID) sender;-(ibaction) Onxmlload: (ID) sender;-(ibaction) Onarchiversave: (ID) sender;-(ibaction) Onarchiverload: (ID) Sender; @end

m file

viewcontroller.m//dataxmlarchiver////Created by God Lin on 14/12/9.//Copyright (c) 2014 Arbboter. All rights reserved.//#import "ViewController.h" #import "Staff.h" @interface Viewcontroller () @end @implementation Viewcontroller@synthesize _textnickname, @synthesize _textemail, @synthesize _textphone; @synthesize _textsex;@ Synthesize _textposition;-(ibaction) Onhidekeyboard: (id) sender{[sender Resignfirstresponder];} -(nsstring*) getdocumentdir{//Get saved file name nsarray* Arraypath = Nssearchpathfordirectoriesindomains (NSDocumentDirectory    , Nsuserdomainmask, YES); return [Arraypath objectatindex:0];}    -(void) textclear{Self._textnickname.text = @ "";    Self._textemail.text = @ "";    Self._textphone.text = @ "";    Self._textsex.text = @ ""; Self._textposition.text = @ "";} XML text saves data, you can save data using an array dictionary, etc.-(ibaction) Onxmlsave: (ID) sender{//Save data to dictionary nsmutabledictionary* dict = [Nsmutabledictiona    Ry Alloc] init];    [Dict setobject:self._textnickname.text forkey:@ "nickname"]; [Dict setobject:self._textemail.text forkey:@ "email"];    [Dict setobject:self._textphone.text forkey:@ "Phone"];    [Dict setobject:self._textsex.text forkey:@ "Sex"];        [Dict setobject:self._textposition.text forkey:@ "position"];    nsstring* pathfile = [self getdocumentdir];        Pathfile = [Pathfile stringbyappendingpathcomponent:@ "Staff.plist"];        Data written to file [Dict writetofile:pathfile Atomically:yes]; uialertview* alert = [[Uialertview alloc] initwithtitle:@ "infomation" message:@ "Save finished" Delegate:nil    cancelbuttontitle:@ "OK" otherbuttontitles:nil];    [Alert show];    Using arc, you do not need to manage memory//[alert release]; [Self textclear];}    -(Ibaction) Onxmlload: (ID) sender{//Get saved file name nsstring* Pathfile = [self getdocumentdir];        Pathfile = [Pathfile stringbyappendingpathcomponent:@ "Staff.plist"];    nsdictionary* dict = [[Nsdictionary alloc] initwithcontentsoffile:pathfile];    Self._textnickname.text = [dict objectforkey:@ "nickname"]; Self._textemail.text = [Dict objectforkey:@ "email"];    Self._textphone.text = [dict objectforkey:@ "Phone"];    Self._textsex.text = [dict objectforkey:@ "sex"];        Self._textposition.text = [Dict objectforkey:@ "position"]; uialertview* alert = [[Uialertview alloc] initwithtitle:@ "infomation" message:@ "Load finished" Delegate:nil    cancelbuttontitle:@ "OK" otherbuttontitles:nil]; [Alert show];}    Archived data-(ibaction) Onarchiversave: (ID) sender{staff* staff = [[Staff alloc] init];    Staff._nickname = Self._textnickname.text;    Staff._email = Self._textemail.text;    Staff._phone = Self._textphone.text;    Staff._sex = Self._textsex.text;        Staff._position = Self._textposition.text;        New binary memory (read/write) nsmutabledata* data = [[Nsmutabledata alloc] init];    Set binary memory data content (read-write) nskeyedarchiver* archiver = [[Nskeyedarchiver alloc] initforwritingwithmutabledata:data];    [Archiver encodeobject:staff forkey:@ "Staff"];        [Archiver finishencoding]; Gets the saved file name nsstring* Pathfile = [selfGetdocumentdir];        Pathfile = [Pathfile stringbyappendingpathcomponent:@ "Staff.archi"];        Save Data (archive) [Data writetofile:pathfile Atomically:yes]; uialertview* alert = [[Uialertview alloc] initwithtitle:@ "infomation" message:@ "Archive finished" Delegate:nil    cancelbuttontitle:@ "OK" otherbuttontitles:nil];    [Alert show]; [Self textclear];}    -(Ibaction) Onarchiverload: (ID) sender{//Get saved file name nsstring* Pathfile = [self getdocumentdir];        Pathfile = [Pathfile stringbyappendingpathcomponent:@ "Staff.archi"];        Read archived files to memory (read only) nsdata* data = [NSData datawithcontentsoffile:pathfile];    Decode memory data (read only) nskeyedunarchiver* unarchiver = [[Nskeyedunarchiver alloc] initforreadingwithdata:data];    staff* staff = [Unarchiver decodeobjectforkey:@ "staff"];        [Unarchiver finishdecoding];    Self._textnickname.text = Staff._nickname;    Self._textemail.text = Staff._email;    Self._textphone.text = Staff._phone;    Self._textsex.text = Staff._sex; Self._textpOsition.text = staff._position; uialertview* alert = [[Uialertview alloc] initwithtitle:@ "infomation" message:@ "Load from Archiver finished" delegate:    Nil cancelbuttontitle:@ "OK" otherbuttontitles:nil]; [Alert show];}    -(void) viewdidload{[Super Viewdidload]; Do any additional setup after loading the view, typically from a nib.}    -(void) didreceivememorywarning {[Super didreceivememorywarning]; Dispose of any resources the can be recreated.} @end

Engineering Code

iOS Development-Data Persistence (i) "Text file + binary archive"