preference(偏好设置)是数据持久化的几个方法中最简单的一个,常用于保存少量数据
代码如下:
//
// ViewController.m
// preference(利用偏好设置保存数据)
//
// Created by Rio.King on 13-9-22.
// Copyright (c) 2013年 Rio.King. All rights reserved.
//
#import "ViewController.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
[self save];
[self read];
}
#pragma mark 保存
-(void)save{
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:@"chaoyuan" forKey:@"username"];
[defaults setFloat:18.6 forKey:@"text_size"];
[defaults setBool:YES forKey:@"auto_login"];
//强制数据保存
[defaults synchronize];
}
#pragma mark 读取
-(void)read{
NSUserDefaults *defualts = [NSUserDefaults standardUserDefaults];
NSString *username = [defualts objectForKey:@"username"];
float textsize = [defualts floatForKey:@"text_size"];
BOOL autoLogin = [defualts boolForKey:@"auto_login"];
NSLog(@"username = %@",username);
NSLog(@"textsize = %0.1f",textsize);
NSLog(@"autoLogin = %i",autoLogin);
}
@end
运行结果如下:
2013-09-22 16:30:42.183 preference(利用偏好设置保存数据)[745:c07] username = chaoyuan
2013-09-22 16:30:42.185 preference(利用偏好设置保存数据)[745:c07] textsize = 18.6
2013-09-22 16:30:42.189 preference(利用偏好设置保存数据)[745:c07] autoLogin = 1
也可以到/Users/Rio/Library/Application Support/iPhone Simulator/6.1/Applications/952F88F8-0A15-4722-903D-9D16D291CA1C/Library/Preference/ 目录下查看生成的.plist文件(Rio是自己的名字,952F88F8-0A15-4722-903D-9D16D291CA1C根据个人会有所不同,一般通过生成时间就可以找到该项目),如我这边生成的文件如下:
![](https://img.laitimes.com/img/9ZDMuAjOiMmIsIjOiQnIsISNyYjM0kzM2EjMykDMzEDMy8CX0Vmbu4GZzNmLn9Gbi1yZtl2Lc9CX6MHc0RHaiojIsJye.jpg)