创建篇(方式一、方式二)
方式一:手动创建CoreData模板
步骤一.新建CoreData模板
One.png
步骤二.创建表
Two.png
Three.png
Four.png
修改表名
修改表名.png
方式二:自动创建CoreData模板
步骤一.新建项目时勾选coreData
勾选coreData.png
步骤二.创建CoreData模板成功
查看.png
使用篇
不解释,直接上部分代码，代码来自互联网，如有侵权，提醒删之
- ViewController.m文件
#import "ViewController.h"
#import "JSONKit.h"
#import "CoreDateManager.h"
#import "NewsCell.h"
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UITableView *newsTableView;
@property (nonatomic, strong) NSMutableArray *resultArray;
@end
@implementation ViewController{
CoreDateManager *coreManager;
}
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(@"%@",NSHomeDirectory());
coreManager = [[CoreDateManager alloc]init];
//更新时间 从NSUserDefaults中读取updateDate这个key对应的value
NSString *updateDate = [[NSUserDefaults standardUserDefaults] objectForKey:@"updateDate"];
if (!updateDate) {//如果无此对象(没有"updateDate"这个key)，表示第一次，那么就读数据(数据来自服务器或者本地的plist文件)写到数据库中
[self writeDate];
}else{
//有此对象说明只要从数据库中(NSUserDefaults的存储路径)读数据
NSTimeInterval update = updateDate.doubleValue;
NSTimeInterval now = [NSDate timeIntervalSinceReferenceDate];
//8小时一更新
if ((now - update)>8*60*60) {
//如果超出八小时就把数据库清空再重新写
[coreManager deleteData];
[self writeDate];
}else{
//没有超过8小时就从数据库中读
NSMutableArray *array = [coreManager selectData:10 andOffset:0];
self.resultArray = [NSMutableArray arrayWithArray:array];
[self.newsTableView reloadData];
}
}
}
-(void)writeDate
{
[[NSUserDefaults standardUserDefaults] setObject:[NSString stringWithFormat:@"%f",[NSDate timeIntervalSinceReferenceDate]] forKey:@"updateDate"];
[[NSUserDefaults standardUserDefaults] synchronize];
//读取信息，我在这里写成本地的了，一般的都是从网上获取数据
NSString *path = [[NSBundle mainBundle]pathForResource:@"News" ofType:@"txt"];
NSString *data = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
// json数据解析成数组
NSArray *array = [data objectFromJSONString];
// NSLog(@"%@",array);
self.resultArray = [NSMutableArray arrayWithCapacity:array.count];
// 遍历数组中的每一个对象，每一个对象都是字典，用dict表示
for (NSDictionary *dict in array) {
// 手写initWithDictionary:方法进行字典转模型
News *info = [[News alloc]initWithDictionary:dict];
// 将每一个模型存储到可变数组self.resultArray中。self.resultArray就是平时所说的模型数组
[self.resultArray addObject:info];
}
// NSLog(@"%@",self.resultArray);
//把数据(模型数组)写到数据库
[coreManager insertCoreData:self.resultArray];
// 刷新newsTableView
[self.newsTableView reloadData];
}
#pragma UITableView
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return self.resultArray.count;
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 90;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"NewsCell";
NewsCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
NSArray *cells = [[NSBundle mainBundle] loadNibNamed:@"NewsCell" owner:self options:nil];
cell = [cells lastObject];
}
News *info = [self.resultArray objectAtIndex:indexPath.row];
// 设置数据
[cell setContent:info];
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
//当你点击时说明要看此条新闻，那么就标注此新闻已被看过
News *info = [self.resultArray objectAtIndex:indexPath.row];
info.islook = @"1";
//改变数据库查看状态
[coreManager updateData:info.newsid withIsLook:@"1"];
//改变resultarry数据
[self.resultArray setObject:info atIndexedSubscript:indexPath.row];
}
@end
- CoreDateManager.h和CoreDateManager.m文件
#import
#import "News.h"
#import
// 必须和ZbModel.xcdatamodeld文件的News表的表名一致。否则当TableName作为entityForName:方法的参数时，由于找不到此表程序就会崩溃
#define TableName @"News"
@interface CoreDateManager : NSObject
@property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
@property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
@property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;
- (void)saveContext;
- (NSURL *)applicationDocumentsDirectory;
//插入数据
- (void)insertCoreData:(NSMutableArray*)dataArray;
//查询
- (NSMutableArray*)selectData:(int)pageSize andOffset:(int)currentPage;
//删除
- (void)deleteData;
//更新
- (void)updateData:(NSString*)newsId withIsLook:(NSString*)islook;
@end
#import "CoreDateManager.h"
@implementation CoreDateManager
@synthesize managedObjectContext = _managedObjectContext;
@synthesize managedObjectModel = _managedObjectModel;
@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;
- (void)saveContext
{
NSError *error = nil;
NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
if (managedObjectContext != nil) {
if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
}
}
#pragma mark - Core Data stack
- (NSManagedObjectContext *)managedObjectContext
{
if (_managedObjectContext != nil) {
return _managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
_managedObjectContext = [[NSManagedObjectContext alloc] init];
[_managedObjectContext setPersistentStoreCoordinator:coordinator];
}
return _managedObjectContext;
}
- (NSManagedObjectModel *)managedObjectModel
{
if (_managedObjectModel != nil) {
return _managedObjectModel;
}
// 加载ZbModel表
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"ZbModel" withExtension:@"momd"];
_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return _managedObjectModel;
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
if (_persistentStoreCoordinator != nil) {
return _persistentStoreCoordinator;
}
// 必须为ZbModel.sqlite，数据都存在了ZbModel.sqlite文件。若为别的文件,则cell上显示不出数据，因为数据源为空。
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"ZbModel.sqlite"];
NSError *error = nil;
_persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
return _persistentStoreCoordinator;
}
#pragma mark - Application's Documents directory
// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory
{
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}
//插入数据
- (void)insertCoreData:(NSMutableArray*)dataArray
{
NSManagedObjectContext *context = [self managedObjectContext];
// 遍历数组中的每一个元素，每一个元素都是模型，用info表示。以后可以通过info方法模型中的属性
for (News *info in dataArray) {
// NSEntityDescription:描述一种抽象数据类型，相当于数据库中的一个表
News *newsInfo = [NSEntityDescription insertNewObjectForEntityForName:TableName inManagedObjectContext:context];
// 将遍历出来的newsid属性赋值给等号左侧的newsid
newsInfo.newsid = info.newsid;
newsInfo.title = info.title;
newsInfo.imgurl = info.imgurl;
newsInfo.descr = info.descr;
newsInfo.islook = info.islook;
NSError *error;
if(![context save:&error])
{
NSLog(@"不能保存：%@",[error localizedDescription]);
}
}
}
//查询
- (NSMutableArray*)selectData:(int)pageSize andOffset:(int)currentPage
{
NSManagedObjectContext *context = [self managedObjectContext];
// 限定查询结果的数量
//setFetchLimit
// 查询的偏移量
//setFetchOffset
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setFetchLimit:pageSize];
[fetchRequest setFetchOffset:currentPage];
// entityForName的参数必须为ZbModel.xcdatamodeld文件的表名，否则程序会因为找不到这个表名而崩溃。
NSEntityDescription *entity = [NSEntityDescription entityForName:TableName inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSError *error;
NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
NSMutableArray *resultArray = [NSMutableArray array];
for (News *info in fetchedObjects) {
NSLog(@"id:%@", info.newsid);
NSLog(@"title:%@", info.title);
[resultArray addObject:info];
}
return resultArray;
}
//删除
-(void)deleteData
{
NSManagedObjectContext *context = [self managedObjectContext];
NSEntityDescription *entity = [NSEntityDescription entityForName:TableName inManagedObjectContext:context];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setIncludesPropertyValues:NO];
[request setEntity:entity];
NSError *error = nil;
NSArray *datas = [context executeFetchRequest:request error:&error];
if (!error && datas && [datas count])// datas中有数据且没有错误
{
for (NSManagedObject *obj in datas)// 遍历datas中的每一个数据
{
// 删除每一个数据
[context deleteObject:obj];
}
if (![context save:&error])
{
NSLog(@"error:%@",error);
}
}
}
//更新
- (void)updateData:(NSString*)newsId withIsLook:(NSString*)islook
{
NSManagedObjectContext *context = [self managedObjectContext];
NSPredicate *predicate = [NSPredicate
predicateWithFormat:@"newsid like[cd] %@",newsId];
//首先你需要建立一个request
NSFetchRequest * request = [[NSFetchRequest alloc] init];
[request setEntity:[NSEntityDescription entityForName:TableName inManagedObjectContext:context]];
[request setPredicate:predicate];//这里相当于sqlite中的查询条件，具体格式参考苹果文档
//https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Predicates/Articles/pCreating.html
NSError *error = nil;
NSArray *result = [context executeFetchRequest:request error:&error];//这里获取到的是一个数组，你需要取出你要更新的那个obj
for (News *info in result) {
info.islook = islook;
}
//保存
if ([context save:&error]) {
//更新成功
NSLog(@"更新成功");
}
}
@end
- 数据源:News.txt文件
[
{
"id": "1",
"title": "明星双11也疯狂晒单晒幸福",
"descr": "一起来看看明星们是如何度过光棍节这个疯狂的日子吧",
"imgurl": "http://img1.cache.netease.com/lady/2013/11/12/2013111209141859623.jpg"
},
{
"id": "2",
"title": "\"代码女神\"脱俗 成最美程序员",
"descr": "\"代码女神\"美貌惊人，她竟然是个程序员",
"imgurl": "http://img3.cache.netease.com/lady/2013/11/12/201311120830507ac45.jpg"
},
{
"id": "3",
"title": "黄菡：安全感源于强大的内心",
"descr": "现代女性首先一定要自立，能够有独立的思想能力。",
"imgurl": "http://img2.cache.netease.com/lady/2013/11/12/20131112084431b6aee.jpg"
},
{
"id": "4",
"title": "女王范冰冰穿衣造型变懒惰",
"descr": "范冰冰这位造型女王近来变得十分\"懒惰\"。",
"imgurl": "http://img6.cache.netease.com/lady/2013/11/12/2013111209111471ed4.jpg"
},
{
"id": "5",
"title": "应采儿产后首拍封面大片",
"descr": "应采儿产后首拍封面大片，尽显迷人气质。",
"imgurl": "http://img4.cache.netease.com/lady/2013/11/12/201311120829029cc3a.jpg"
},
{
"id": "6",
"title": "张亮父子示范型男亲子装",
"descr": "惹人爱亲子装系列，今天小编盘点张亮父子的时尚型男亲子装。",
"imgurl": "http://img3.cache.netease.com/lady/2013/11/12/201311120904577c9a0.jpg"
},
{
"id": "7",
"title": "本14岁清纯萝莉走红网络",
"descr": "日本14岁清纯萝莉走红网络，外表清纯可爱。",
"imgurl": "http://img1.cache.netease.com/lady/2013/11/12/20131112083235f5b8b.jpg"
},
{
"id": "8",
"title": "石头诗龄学包饺子 王岳伦刷碗",
"descr": "近日，王诗龄和石头在郭涛的指导下包出的饺子有模有样。",
"imgurl": "http://img2.cache.netease.com/lady/2013/11/12/20131112091709fa3dc.jpg"
},
{
"id": "9",
"title": "MTV音乐大奖 李宇春战袍加身",
"descr": "美国，万人瞩目的MTV欧洲音乐大奖举行。",
"imgurl": "http://img4.cache.netease.com/lady/2013/11/12/20131112090132f4647.jpg"
},
{
"id": "10",
"title": "吴奇隆公开承认与刘诗诗恋情",
"descr": "发微博称\"很珍惜這份得之不易的感情\"，刘诗诗予以转发。",
"imgurl": "http://img4.cache.netease.com/3g/2013/11/13/2013111302215625fea.jpg"
}
]
效果篇
101.150.gif