ios24-数据持久化-对象归档

1.创建一个单例模式

//

//  ios24_saveObjectToFileViewController.h

//  ios24-saveObjectToFile

//

//  Created by  on 13-6-18.

//  Copyright 2013年 __MyCompanyName__. All rights reserved.

//

#import <UIKit/UIKit.h>

@interface ios24_saveObjectToFileViewController : UIViewController<UITextFieldDelegate>

{

    UITextField *tfId;

    UITextField *tfName;

    UITextField *tfClass;

}

@property (nonatomic,retain) IBOutlet UITextField *tfId;

@property (nonatomic,retain) IBOutlet UITextField *tfName;

@property (nonatomic,retain) IBOutlet UITextField *tfClass;

-(IBAction)save;

-(IBAction)read;

-(NSString *)getFilePath;

@end

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

//

//  ios24_saveObjectToFileViewController.m

//  ios24-saveObjectToFile

//

//  Created by  on 13-6-18.

//  Copyright 2013年 __MyCompanyName__. All rights reserved.

//

#import "ios24_saveObjectToFileViewController.h"

#import "Student.h"

@implementation ios24_saveObjectToFileViewController

@synthesize tfId,tfName,tfClass;

- (void)didReceiveMemoryWarning

{

    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.

}

#pragma mark - View lifecycle

//保存数据

-(IBAction)save{

//实现保存

    NSString *savePath=[self getFilePath];

    //定义data

    NSMutableData *data=[[NSMutableData alloc]init ];

    //定义压缩的工具类

    NSKeyedArchiver *archer=[[NSKeyedArchiver alloc]initForWritingWithMutableData:data];

    //保存的对象

    Student *stu=[[Student alloc]init];

    stu.studentId=tfId.text;

    stu.studentName=tfName.text;

    stu.studentClass=tfClass.text;

    //压缩

   
    [archer encodeObject:stu forKey:@"stuobj"];

    [archer finishEncoding];

    //写入文件

    [data writeToFile:savePath atomically:YES];

    NSLog(@"保存成功");

   
   
}

//读取数据

-(IBAction)read{

    //获取path

    NSString *readPath=[self getFilePath];

    //获取文件的二进制流

    NSData *data=[[NSData alloc]initWithContentsOfFile:readPath];

    if (data.length>0) {