iOS如何保存用户信息之plist文件/归档

在iOS开发过程中注册登录往往是必不可少的, 那么如何保存用户的这些注册信息在本地呢?

• 示例

这里写图片描述

这里我创建了一个名为LoginController的控制器, 有五个NSString属性, 分别是str0...str4, 和一个TextField的数组; 同时还有四个按钮, 作用分别是保存信息到plist文件, 加载pilst文件保存的信息, 归档信息, 加载归档文件里的信息.

LoginController.h代码:

@interface LoginController : UIViewController<NSCoding>
@property (nonatomic) NSArray<UITextField *> *tfArray;

@property (nonatomic, copy) NSString *str0;
@property (nonatomic, copy) NSString *str1;
@property (nonatomic, copy) NSString *str2;
@property (nonatomic, copy) NSString *str3;
@property (nonatomic, copy) NSString *str4;

@end

注意必须要遵守NSCoding, 否则无法实现归档和解档

保存方式一: plist文件保存

LoginController.m代码:

• 保存按钮点击事件

 //保存数据
- (void)saveBtnClick {
    NSMutableArray *dataArr = [NSMutableArray new];
    for (int i = 0; i < self.tfArray.count; i++) {
        [dataArr addObject:self.tfArray[i].text];
    }
    NSString *str = [NSHomeDirectory() stringByAppendingString:@"/Documents/person.plist"];
    [dataArr writeToFile:str atomically:YES];
    NSLog(@"用户信息保存路径: %@", str);
}

• 加载plist文件保存的信息的按钮点击事件

- (void)loadBtnClick {
    NSString *str = [NSHomeDirectory() stringByAppendingString:@"/Documents/person.plist"];
    NSArray *arr = [NSArray arrayWithContentsOfFile:str];
    for (int i = 0; i < self.tfArray.count; i++) {
        self.tfArray[i].placeholder = arr[i];
    }
}

保存方式二: 归档

• 归档按钮点击事件

- (void)archiveBtnClick {
    LoginController *per = [[LoginController alloc] init];
    per.str0 = self.tfArray[0].text;
    per.str1 = self.tfArray[1].text;
    per.str2 = self.tfArray[2].text;
    per.str3 = self.tfArray[3].text;
    per.str4 = self.tfArray[4].text;
    NSLog(@"per------%@%@%@", per.str0, per.str1, per.str3);
    NSMutableData *data = [[NSMutableData alloc] init];
    NSKeyedArchiver *archive = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
    //归档数据
    [archive encodeObject:per forKey:@"me"];
    //结束归档
    [archive finishEncoding];
    //将归档数据写入磁盘
    NSString *str = [NSHomeDirectory() stringByAppendingString:@"/Documents/guidang.zhengmengxin"];
    [data writeToFile:str atomically:YES];
    NSLog(@"归档:%@", str);
}

• 解档按钮加载解档内容事件

- (void)loadArchiveBtnClick {
    NSString *str = [NSHomeDirectory() stringByAppendingString:@"/Documents/guidang.zhengmengxin"];
    NSData *data = [NSData dataWithContentsOfFile:str];
    NSKeyedUnarchiver *unarchive = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
    //解档数据
    LoginController *vc = [unarchive decodeObjectForKey:@"me"];
    [unarchive finishDecoding];
    NSLog(@"vc------%@%@%@", vc.str0, vc.str1, vc.str3);
    self.tfArray[0].text = vc.str0;
    self.tfArray[1].text = vc.str1;
    self.tfArray[2].text = vc.str2;
    self.tfArray[3].text = vc.str3;
    self.tfArray[4].text = vc.str4;
}

必须实现的NSCoding协议方法

我们先来看看NSCoding协议的API

@protocol NSCoding

- (void)encodeWithCoder:(NSCoder *)aCoder;
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder; // NS_DESIGNATED_INITIALIZER

@end

LoginController.m中实现协议的两个方法:

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
    if (self = [super initWithCoder:aDecoder]) {
        self.str0 = [aDecoder decodeObjectForKey:@"str0"];
        self.str1 = [aDecoder decodeObjectForKey:@"str1"];
        self.str2 = [aDecoder decodeObjectForKey:@"str2"];
        self.str3 = [aDecoder decodeObjectForKey:@"str3"];
        self.str4 = [aDecoder decodeObjectForKey:@"str4"];
    }
    return self;
}

- (void)encodeWithCoder:(NSCoder *)aCoder {
    [aCoder encodeObject:self.str0 forKey:@"str0"];
    [aCoder encodeObject:self.str1 forKey:@"str1"];
    [aCoder encodeObject:self.str2 forKey:@"str2"];
    [aCoder encodeObject:self.str3 forKey:@"str3"];
    [aCoder encodeObject:self.str4 forKey:@"str4"];
}