Operation of files in OC (loading existing file data, accessing files)

----------------------------File.h-------------------------------

#import <Foundation/Foundation.h>

@interface Filehelper:nsobject

+ (Nsmutablearray *) loaddata;//load data and save in array

+ (void) Savestudentdata: (Nsmutablearray *) dataarr;//save data in array

+ (Nsmutablearray *) loadstudentdata;//take students as an example

@end

----------------------------------------------------------------

----------------------------FILE.M-----------------------------

#import "File.h"

/** Set File Save path */

Static NSString * Data_info_file = (NSString *) path;

@implementation File

Load files,

+ (Nsmutablearray *) Loaddatafromfile: (NSString *) filename{

return [Nskeyedunarchiver Unarchiveobjectwithfile:filename];

}

Save File

+ (void) SaveData: (Nsmutablearray *) Dataarr tofile: (NSString *) filename{

[Nskeyedarchiver Archiverootobject:dataarr Tofile:filename];

}

Load Student Data

+ (Nsmutablearray *) loadstudentdata{

Self means receiver that invokes the current method.

Who calls the current method, self means who

return [self loaddatafromfile:student_info_file];

}

Save Student data

+ (void) Savestudentdata: (Nsmutablearray *) dataarr{

[Self Savedata:dataarr tofile:student_info_file];

}

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----------------------Student---------------------------------

#import <Foundation/Foundation.h>

@interface student:nsobject<nscoding>

School number, name, password, department, class, telephone

@property (nonatomic, copy) NSString * number;

@property (nonatomic, copy) NSString * name;

@property (nonatomic, copy) NSString * password;

@property (nonatomic, copy) NSString * Department;

@property (nonatomic, copy) NSString * grade;

@property (nonatomic, copy) NSString * phone;

-(ID) Initwithnumber: (NSString *) number andname: (NSString *) name Andpassword: (NSString *) password anddepartment: ( NSString *) Department Andgrade: (NSString *) grade Andphone: (NSString *) phone;

@end

-------------------------------------------------------------

-----------------------STUDENT.M--------------------------

#import "Student.h"

@implementation Student

/** Initializing student Objects */

-(ID) Initwithnumber: (NSString *) number andname: (NSString *) name Andpassword: (NSString *) password anddepartment: ( NSString *) Department Andgrade: (NSString *) grade Andphone: (NSString *) phone{

self = [super init];

if (self) {

Self.number = number;

Self.name = name;

Self.password = password;

self.department = Department;

Self.grade = grade;

Self.phone = phone;

}

return self;

}

/** serialization, Function: Save the file via the iOS protocol */

-(void) Encodewithcoder: (Nscoder *) acoder{

[Acoder encodeObject:self.number forkey:@ "number"];

[Acoder encodeObject:self.name forkey:@ "name"];

[Acoder encodeObject:self.password forkey:@ "password"];

[Acoder encodeObject:self.department forkey:@ "department"];

[Acoder encodeObject:self.grade forkey:@ "Grade"];

[Acoder encodeObject:self.phone forkey:@ "Phone"];

}

/** deserialization, function: Read files via iOS protocol */

-(ID) Initwithcoder: (Nscoder *) adecoder{

self = [super init];

if (self) {

Self.number = [Adecoder decodeobjectforkey:@ "number"];

Self.name = [Adecoder decodeobjectforkey:@ "name"];

Self.password = [Adecoder decodeobjectforkey:@ "password"];

Self.department = [Adecoder decodeobjectforkey:@ "department"];

Self.grade = [Adecoder decodeobjectforkey:@ "grade"];

Self.phone = [Adecoder decodeobjectforkey:@ "Phone"];

}

return self;

}

/** Print out basic student information * *

-(NSString *) description{

return [NSString stringwithformat:@ "%@%@%@%@%@", Self.number, Self.name, Self.department, Self.grade, self.ph One];

}

@end

----------------------------------------------------------

---------------Start.h-----------------------------------

+ (void) Savedataafterappdown;

+ (void) Loaddatabeforeapprun;

----------------------------------------------------------

----------------------START.M---------------------------

+ (void) Loaddatabeforeapprun

{

/** loads the student information file and initializes an array of student information to hold the student's basic information * *

Studentarr = [Filehelper loadstudentdata];

if (Studentarr = = nil) {

Studentarr = [[Nsmutablearray alloc]init];

}

}

/** Save the data for this time * *

+ (void) savedataafterappdown{

NSLog (@ "System exited, saving information ... ");

[File Savestudentdata:studentarr];

}

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Operation of files in OC (loading existing file data, accessing files)