控制器和应用数据存储

1、UINavigationController, 继承UIViewController，UINavigationController以栈的形式保存子控制器

    1)把控制器添加到导航控制器栈里有两种方式：

       导航控制器 UINavigationController *nav = [[UINavigationController alloc] init];

       比如有一个控制器：UIViewController *control = [[UIViewController alloc] init];

       第一种方式:[nav addChildViewController:control];

       第二种方式:[nav pushViewController:control animated:YES];

    2)从导航控制器栈里中移出栈顶的控制器：- (UIViewController *)popViewControllerAnimated:(BOOL)animated;

       回到指定的子控制器：- (NSArray *)popToViewController:(UIViewController *)viewController ainimated:(BOOL)animated;

       回到根控制器：- (NSArray *)popToRootViewController ainimated:(BOOL)animated;

    3）UINavigationItem的属性：

//左上角的返回按钮
@property(nonatomic, retain)  UIBarButtonItem  *backBarButtonItem;

//中间的标题视图
@property(nonatomic, retain)  UIView  *titleView;

//中间的标题文字
@property(nonatomic, copy)  NSString  *title;

//左上角的视图
@property(nonatomic, retain)  UIBarButtonItem  *leftBarButtonItem;

//右上角的视图
@property(nonatomic, retain)  UIBarButtonItem  *rightButtonItem;

2、UIStoryboardSegue : 每个Segue有三个属性：

//唯一标识
@property(nonatomic, readonly)  NSString  *identifier;

//来源控制器
@property(nonatomic, readonly)  id sourceViewController;

//目标控制器
@property(nonatomic, readonly)  id destinationViewController;

执行segue的时候，跳转之前会调用一个方法：- (void)prepareForSegue:(UIStoryboardSegue *)segue  sender:(id)sender;

一般可以在这个方法做一些准备操作，例如给下一个控制器传值

3、ios应用常用的数据的存储方式主要有：

   1）、plist (利用xml属性列表归档NSDictionary、NSArray、NSData、NSNumber等系统类型数据）

   2）、NSUserDefaults 偏好设置

   3）、NSKeydeArchiver归档（一般用来存储自定义对象）

   4）、SQLite(关系型数据库，不能直接存储对象，使用sql语句序列化对象存储)

   5）、Core Data (对象型数据库，吧内部环境屏蔽）

4、应用程序沙盒（模拟器沙盒大概路径：/Users/tan/Library/Developer/CoreSimulator/Devices/......）

   每个应用程序都有自己的应用沙盒，用来和其他程序隔离；

   沙盒的文件系统目录有三个：Documents、Library(又包含Caches和Preferences)、tmp；

   1）、应用程序包包含了所有的资源文件和可执行文件；  

   2）、Documents保存应用运行时生成的需要持久化的数据，iTunes同步设备时会备份该目录；

   3）、tmp保存应用运行时所需的临时数据，使用完毕后再将相应的文件从该目录删除。应用没有运行时，系统也可能会清除该目录下的文件。iTunes同步设备时，不会备份该目录；

   4）、Library/Caches 保存应用运行时生成的非重要的需要持久化的数据，iTunes同步设备时不会备份该目录；

   5）、Library/Prefences保存应用的所有偏好设置，iTunes同步设备时会备份该目录

   测试获取应用程序沙盒下和真机下Documents路径和安装包资源文件路径方法：

   

//沙盒Documents路径 ： NSSearchPathForDirectoriesInDomains函数第三个参数布尔类型expandTilde表示是否显示全路径
    NSString *path1 = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
    NSString *path2 = [NSHomeDirectoryForUser(nil) stringByAppendingPathComponent:@"Documents"];
    NSString *path3 = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *path4 = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, NO) lastObject];
    NSLog(@"path1 = %@", path1);
    NSLog(@"path2 = %@", path2);
    NSLog(@"path3 = %@", path3);
    NSLog(@"path4 = %@", path4);
    
    //安装包资源文件路径
    NSString *indexUrl = [[NSBundle mainBundle] pathForResource:@"index" ofType:@"html"];
    NSLog(@"indexUrl: %@", indexUrl);

/*
     模拟器测试打印日志：
     path1 = /Users/PX/Library/Developer/CoreSimulator/Devices/57E9C8A1-2AB2-48C9-9304-254BF841DC2D/data/Containers/Data/Application/948A9B33-FEB7-479B-90FB-F27D573663DF/Documents
     path2 = /Users/PX/Library/Developer/CoreSimulator/Devices/57E9C8A1-2AB2-48C9-9304-254BF841DC2D/data/Containers/Data/Application/948A9B33-FEB7-479B-90FB-F27D573663DF/Documents
     path3 = /Users/PX/Library/Developer/CoreSimulator/Devices/57E9C8A1-2AB2-48C9-9304-254BF841DC2D/data/Containers/Data/Application/948A9B33-FEB7-479B-90FB-F27D573663DF/Documents
     path4 = ~/Documents
     indexUrl: /Users/PX/Library/Developer/CoreSimulator/Devices/57E9C8A1-2AB2-48C9-9304-254BF841DC2D/data/Containers/Bundle/Application/67C8E4C2-3DF1-4673-8FE9-48397EDA7759/tan_IOSFuXi.app/index.html
     
     真机测试打印日志：
     path1 = /var/mobile/Containers/Data/Application/CC29D2BC-F10B-41F4-A1CD-239E379604F6/Documents
     path2 = /var/mobile/Containers/Data/Application/CC29D2BC-F10B-41F4-A1CD-239E379604F6/Documents
     path3 = /var/mobile/Containers/Data/Application/CC29D2BC-F10B-41F4-A1CD-239E379604F6/Documents
     path4 = ~/Documents
     indexUrl: /var/mobile/Containers/Bundle/Application/2B0645D3-0B3F-46BF-841C-202B5A5A0C4B/tan_IOSFuXi.app/index.html
     */

 5、应用程序数据存储方式示例代码：

//定义两个属性
@property (weak, nonatomic) IBOutlet UITextField *txtPlist; //输入信息
@property (weak, nonatomic) IBOutlet UILabel *lblPlist; //展示信息

   1）、使用plist文件来存储系统类数据

//将字典数据存入*.plist文件中
- (IBAction)savePlist:(id)sender{
    //沙盒Documents文件夹路径 最后那个参数expandTilde代表是否展开完整路径
    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"tan.plist"];

    NSDictionary *dic = @{@"msg": self.txtPlist.text};
    //原子的写入文件中 
    if ([dic writeToFile:path atomically:YES]){
        self.txtPlist.text = @"保存成功";
    }
    else{
        self.txtPlist.text = @"保存失败";
    }
}

//* 读取数据plist文件数据 */
- (IBAction)readPlist:(id)sender{
    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"tan.plist"];
    NSDictionary *dic = [NSDictionary dictionaryWithContentsOfFile:path];
    self.lblPlist.text = [NSString stringWithFormat:@"%@: %@", [[dic allKeys] firstObject], [[dic allValues] lastObject]];
}

   

   2）、使用偏好设置存储

  

/* 保存数据到用户偏好设置中 */
- (IBAction)saveDataToUserPreference:(id)sender{
    NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
    // 自动帮我们生成一个plist文件存放在偏好设置的文件夹
    [ud setObject:self.txtPlist.text forKey:@"msg"];
    
    // 同步：把内存中的数据和沙盒同步
    [ud synchronize];
    self.txtPlist.text = @"存储到偏好设置OK";
}

/* 从用户偏好设置中读取数据 */
- (IBAction)readDataByUserPreference:(id)sender{
    NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
    self.lblPlist.text = [ud objectForKey:@"msg"];
}

  

   

   3)、使用NSKeyedArchiver对自定义对象进行归档， 使用NSKeyedUnarchiver解析归档对象

      首先自定义类需要实现NSCoding协议，然后实现方法

     - (void)encodeWithCoder:(NSCoder *)aCoder; //定义自定义类哪些属性需要归档，如何归档

     - (id)initWithCoder:(NSCoder *)aDecoder; // 定义归档对象解析时哪些属性需要解析，如何解析

     如果父类也遵守了NSCoding协议，应该在encodeWithCoder:方法中加上一句：[super encodeWithCode:encode];

     确保继承的实例变量也能被编码，即也能被归档

     应该在initWithCoder:方法中加上一句：self = [super initWithCoder:decoder];

     确保继承的实例变量也能被解码，即也能被恢复

   

#import <Foundation/Foundation.h>

@interface TanPerson : NSObject <NSCoding>

@property (nonatomic, copy) NSString *name;
@property (nonatomic, assign) int age;
@property (nonatomic, copy) NSString *email;
@property (nonatomic, copy) NSString *address;

+ (instancetype)tanPersonWithDict:(NSDictionary *)dict;
- (instancetype)initWithDict:(NSDictionary *)dict;

@end

   

#import "TanPerson.h"

@implementation TanPerson

+ (instancetype)tanPersonWithDict:(NSDictionary *)dict{
    return [[self alloc] initWithDict:dict];
}

- (instancetype)initWithDict:(NSDictionary *)dict{
    if (self = [super init]){
        [self setValuesForKeysWithDictionary:dict];
    }
    return self;
}

/**
 对象归档时调用
 哪些属性需要归档，又如何归档
 */
- (void)encodeWithCoder:(NSCoder *)aCoder{
    [aCoder encodeObject:_address forKey:@"tan_address"];
    [aCoder encodeInt:_age forKey:@"age"];
    [aCoder encodeObject:_name forKey:@"tan_name"];
}

/**
 解析对象时调用
 哪些属性需要解析，如何解析
 */
- (id)initWithCoder:(NSCoder *)aDecoder{
    if (self = [super init]){
        _address = [aDecoder decodeObjectForKey:@"tan_address"];
        _age = [aDecoder decodeIntForKey:@"age"];
        _name = [aDecoder decodeObjectForKey:@"tan_name"];
    }
    return self;
}
@end

     //控制器内方法

/* NSKeyedArchiver归档 用来存储自定义对象 */
- (IBAction)saveDataToArchiver:(id)sender{
    TanPerson *person = [[TanPerson alloc] init];
    person.age = 25;
    person.address = self.txtPlist.text;
    person.name = @"呼呼";
    
    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"tanPerson.data"];
    
    if ([NSKeyedArchiver archiveRootObject:person toFile:path]){
        self.txtPlist.text = @"对象归档OK了";
    }
    else{
        self.txtPlist.text = @"对象归档行动失败！";
    }
}

/* 使用NSKeyedUnarchiver解析归档对象 */
- (IBAction)readyDataByArchiver:(id)sender{
    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"tanPerson.data"];
    
    TanPerson *person = [NSKeyedUnarchiver unarchiveObjectWithFile:path];
    self.lblPlist.text = [NSString stringWithFormat:@"name: %@, age: %d, address: %@", person.name, person.age, person.address];
}

    4）使用NSKeyedArchiver归档多个对象和解析

/* 使用NSKeyedArchiver归档多个对象 */
- (IBAction)saveMulObjectByArchive:(id)sender{
    TanPerson *person1 = [[TanPerson alloc] init];
    person1.name = @"小毛";
    TanPerson *person2 = [[TanPerson alloc] init];
    person2.name = @"小亲";
    
    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"tanMulPerson.data"];
    
    //NSData可以为一些数据提供临时存储空间，以便随后写入文件，或者存放从磁盘读取的文件内容
    NSMutableData *data = [NSMutableData data]; //新建一块可变数据区
    
    //将数据区连接到一个NSKeyedArchiver对象
    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
    //开始存档对象，存档的数据都会存储到data中
    [archiver encodeObject:person1 forKey:@"perOne"];
    [archiver encodeObject:person2 forKey:@"perTwo"];
    //存档完毕  必须调用
    [archiver finishEncoding];
    //将存档的数据存入文件
    [data writeToFile:path atomically:YES];
    
    self.txtPlist.text = @"多个对象存档完成了";
}

/* 使用NSKeyedUnArchiver解析多个归档对象 */
- (IBAction)readMulObjectByArchiver:(id)sender{
    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"tanMulPerson.data"];
    //将数据读取到data上
    NSMutableData *data = [NSMutableData dataWithContentsOfFile:path];
    
    //解析数据
    NSKeyedUnarchiver *unArchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
    TanPerson *person1 = [unArchiver decodeObjectForKey:@"perOne"];
    TanPerson *person2 = [unArchiver decodeObjectForKey:@"perTwo"];
    
    [unArchiver finishDecoding]; //恢复完毕 可以不调用
    
    self.lblPlist.text = [NSString stringWithFormat:@"name1: %@, name2: %@", person1.name, person2.name];
}