NSManagedObjectContext 数据库管理上下文

#import "ViewController.h"

#import <CoreData/CoreData.h>
#import "Person+CoreDataProperties.h"
#import "PetsViewController.h"

@interface ViewController ()<UITableViewDataSource, UITableViewDelegate>

// 数据库管理上下文
@property (nonatomic, strong) NSManagedObjectContext *context;

// 数据源数组
@property (nonatomic, strong) NSMutableArray *dataSource;
// 界面展示
@property (nonatomic, strong) UITableView *tableView;


@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    // 导航栏元素
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(addAction)];
    
    // 准备数据库
    [self prepareForCoreData];
    
    
    // 实例化tableView
    [self initTableView];
}

- (void)initTableView {
    self.tableView = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain];
    self.tableView.delegate = self;
    self.tableView.dataSource = self;
    
    [self.view addSubview:self.tableView];
}

/** 导航栏右上角元素点击事件 */
- (void)addAction {
    
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"提示" message:@"请输入用户的信息" preferredStyle:UIAlertControllerStyleAlert];
    
    // 用户名字输入框
    [alert addTextFieldWithConfigurationHandler:^(UITextField *  textField) {
        
        textField.placeholder = @"请输入用户名称";
        textField.font = [UIFont systemFontOfSize:13];
    }];
    
    // 身份证输入框
    [alert addTextFieldWithConfigurationHandler:^(UITextField *  textField) {
       
        textField.placeholder = @"请输入身份证号码";
        textField.font = [UIFont systemFontOfSize:13];
    }];
    
    // 取消按钮
    UIAlertAction *actionCancel = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
    // 保存按钮
    UIAlertAction *actionDone = [UIAlertAction actionWithTitle:@"保存" style:UIAlertActionStyleDefault handler:^(UIAlertAction *  action) {
        
        // 触发增操作
        [self saveAction:alert];
    }];
    
    
    [alert addAction:actionCancel];
    [alert addAction:actionDone];
    
    [self presentViewController:alert animated:YES completion:nil];
}

// 弹窗保存按钮事件
- (void)saveAction:(UIAlertController *)alert {
    
    // 1. 获取两个输入框里面的内容
    UITextField *usernameText = alert.textFields.firstObject;
    UITextField *personIDText = alert.textFields.lastObject;
    
    NSString *username = usernameText.text;
    NSNumber *personID = @(personIDText.text.integerValue);
    
    // 2. person模型
    Person *p = [NSEntityDescription insertNewObjectForEntityForName:@"Person" inManagedObjectContext:self.context];
    
    p.name = username;
    p.personID = personID;
    
    // 3. 保存到本地
    [self.context save:nil];
    
    // 4. 界面展示
    [self.dataSource addObject:p];
    [self.tableView reloadData];
}


#pragma mark ------ 协议 -------
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    
    return self.dataSource.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    static NSString *reuseid = @"cell";
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:reuseid];
    
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:reuseid];
    }
    
    // 展示
    Person *p = self.dataSource[indexPath.row];
    
    cell.textLabel.text = p.name;
    cell.detailTextLabel.text = [NSString stringWithFormat:@"%@", p.personID];
    
    
    
    return cell;
    
}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    // 获取这一行显示的数据
    Person *p = self.dataSource[indexPath.row];
    
    // 1. 从界面显示删除
    [self.dataSource removeObject:p];
    [self.tableView reloadData];
    
    // 2. 从本地缓存中删除
    [self.context deleteObject:p];
    [self.context save:nil];
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    
    PetsViewController *vc = [[PetsViewController alloc] init];
    
    // 获取到当前要显示的person的模型, 并传给下一个界面
    vc.p = self.dataSource[indexPath.row];
    // 把这个界面实例化好的数据库管理上下文, 传给下个界面使用
    vc.context = self.context;
    
    [self.navigationController pushViewController:vc animated:YES];
}

#pragma mark ------ 数据库操作 -----
- (void)prepareForCoreData {
    
    // 1. 实例化管理上下文
    self.context = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
    
    // 获取路径
    NSString *path = [[NSBundle mainBundle] pathForResource:@"CoreDataDemo" ofType:@"momd"];
    
    // 实例化数据管理模型
    NSManagedObjectModel *model = [[NSManagedObjectModel alloc] initWithContentsOfURL:[NSURL fileURLWithPath:path]];
    
    // 实例化协调器
    NSPersistentStoreCoordinator *coordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:model];
    
    // 设置数据库文件保存的路径
    // ~/
    NSString *storePath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject stringByAppendingString:@"/person.db"];
    
    // 设置存储类型
    [coordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:[NSURL fileURLWithPath:storePath] options:nil error:nil];
    
    // 2. 设置数据存储的协调器
//    self.context.persistentStoreCoordinator = coordinator;
    [self.context setPersistentStoreCoordinator:coordinator];
}

// 查询所有数据
- (NSArray *)findAll {
    
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"];
    
    return [self.context executeFetchRequest:request error:nil];
}





#pragma mark ------ 懒加载实现 --------
- (NSMutableArray *)dataSource {
    if (_dataSource == nil) {
        _dataSource = [[NSMutableArray alloc] init];
        // 读取本地缓存的数据, 并默认填充到数据源数组中
        [_dataSource addObjectsFromArray:[self findAll]];
    }
    
    return _dataSource;
}
@end

Person+CoreDataProperties类

#import "Person.h"

NS_ASSUME_NONNULL_BEGIN

@interface Person (CoreDataProperties)

@property (nullable, nonatomic, retain) NSString *name;
@property (nullable, nonatomic, retain) NSNumber *personID;
@property (nullable, nonatomic, retain) NSSet *pets;

@end

@interface Person (CoreDataGeneratedAccessors)

- (void)addPetsObject:(NSManagedObject *)value;
- (void)removePetsObject:(NSManagedObject *)value;
- (void)addPets:(NSSet *)values;
- (void)removePets:(NSSet *)values;

@end

NS_ASSUME_NONNULL_END

#import "Person+CoreDataProperties.h"

@implementation Person (CoreDataProperties)

@dynamic name;
@dynamic personID;
@dynamic pets;

@end

Person类

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>

NS_ASSUME_NONNULL_BEGIN

@interface Person : NSManagedObject

// Insert code here to declare functionality of your managed object subclass

@end

NS_ASSUME_NONNULL_END

#import "Person+CoreDataProperties.h"

#import "Person.h"

@implementation Person

// Insert code here to add functionality to your managed object subclass

@end

Dog+CoreDataProperties类

#import "Dog.h"

NS_ASSUME_NONNULL_BEGIN

@interface Dog (CoreDataProperties)

@property (nullable, nonatomic, retain) NSString *name;
@property (nullable, nonatomic, retain) NSString *kind;
@property (nullable, nonatomic, retain) Person *master;

@end

NS_ASSUME_NONNULL_END

#import "Dog+CoreDataProperties.h"

@implementation Dog (CoreDataProperties)

@dynamic name;
@dynamic kind;
@dynamic master;

@end

Dog类

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>

@class Person;

NS_ASSUME_NONNULL_BEGIN

@interface Dog : NSManagedObject

// Insert code here to declare functionality of your managed object subclass

@end

NS_ASSUME_NONNULL_END

#import "Dog+CoreDataProperties.h"

#import "Dog.h"
#import "Person.h"

@implementation Dog

// Insert code here to add functionality to your managed object subclass

@end

coreData1.png

coreData2.png

coreData3.png
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