CoreData
2015-10-16 05:53 真实16 阅读(222) 评论(0) 编辑 收藏 举报//
// ViewController.m
// UI-NO-42-1 CoreData-1
//
// Created by 容伟 on 15/10/5.
// Copyright (c) 2015年 容伟. All rights reserved.
//
/*
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CoreData:不需要编写任何SQL语句,直接存取对象;与关系型数据库相比如图：
在CoreData里面 存储的都是NSManagerObject具体的对象
CoreData负责管理这些对象之间的关系
只要Xcode里面建立了visual map 就可以新建对象
并把对象添加到数据库里面,同时也可以删除、查询
modle里面包含了实体entity，相当于属性（没写完）
注意：“实体”的名字首字母必须是大写，否则报错 ！！！！
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操作coreData
1、不管增删改查都需要先初始化 上下文[app managedObjectContext]
2、插入具体内容到上下文
+ (id)insertNewObjectForEntityForName:(NSString *)entityName inManagedObjectContext:(NSManagedObjectContext *)context;
3、保存 saveContext
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谓词NSPredicate 条件语句
1、比较运算符>,<,==,>=,<=,!=
可用于数值和字符串等的比较
如：@“age >= 23” 筛选 年纪大于23岁的元素
2、范围运算符：IN、BETWEEN
例：@"number BETWEEN {10,50}"
@"address IN {'河南','北京'}"
3、字符串本身:SELF
例：@“SELF == ‘APPLE’"
4、字符串相关：BEGINSWITH、ENDSWITH、CONTAINS
例：@"name CONTAIN[cd] 'ang'" //包含某个字符串
@"name BEGINSWITH[c] 'sh'" //以某个字符串开头
@"name ENDSWITH[d] 'ang'" //以某个字符串结束
注:[c]不区分大小写[d]不区分发音符号即没有重音符号[cd]既不区分大小写，也不区分发音符号。
(5)通配符：
LIKE 模糊查询
例：@"name LIKE[cd] '*b*'" *代表通配符,表示前面后面 有一个或多个字符
6、 正则表达式
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读取coreData
1、读取managedObjectModel
2、找到里面所有实体的名字[model entitiesByName]
3、找到要读取的实体NSEntityDescription *entry = entryDic[@"UserInfo"];
4、初始化 查询对象 NSFetchRequest *request = [[NSFetchRequest alloc]init];
5、通过上下文 查找 NSArray *list = [context executeFetchRequest:request error:nil];
-------------------------------------------------------------
*/
#import "ViewController.h"
#import "AppDelegate.h"
#import "PostView.h"
#import "Message.h"
#import "UserInfo.h"
@interface ViewController ()<UITableViewDataSource, UITableViewDelegate>
{
UITableView *showView;
PostView *postView; // 发布界面
NSArray *dataList;
}
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.edgesForExtendedLayout = UIRectEdgeNone;
self.navigationController.navigationBar.translucent = NO;
self.tabBarController.tabBar.translucent = NO;
[self addRightButtonItem];
[self addShowView];
[self loadData];
}
- (void)addRightButtonItem {
UIBarButtonItem *right = [[UIBarButtonItem alloc] initWithTitle:@"Add" style:UIBarButtonItemStylePlain target:self action:@selector(createPostView)];
self.navigationItem.rightBarButtonItem = right;
}
// 发布界面
- (void)createPostView {
if (postView) {
self.navigationItem.rightBarButtonItem.title = @"Add";
[self done];
[postView removeFromSuperview];
postView = nil;
return;
}
self.navigationItem.rightBarButtonItem.title = @"Done";
postView = [[PostView alloc] initWithFrame:
[UIScreen mainScreen].bounds];
[self.view addSubview:postView];
}
- (void)done {
[postView.titleTextField resignFirstResponder];
[postView.contentTextField resignFirstResponder];
// 如果输入了内容 就将之保存到数据库
if (postView.titleTextField.text.length!=0 && postView.contentTextField.text!=0) {
[self addEntity];
}else{
// 没有输入内容
}
// [showView reloadData];
}
- (void)addEntity {
// 操作coreData
// 1、不管增删改查都需要先初始化 上下文[app managedObjectContext]
// 2、插入具体内容到上下文
// + (id)insertNewObjectForEntityForName:(NSString *)entityName inManagedObjectContext:(NSManagedObjectContext *)context;
// 3、保存 saveContext
// 1、初始化上下文
NSManagedObjectContext *context = [[AppDelegate appDelegate] managedObjectContext];
// 2、实体描述
Message *message = [NSEntityDescription insertNewObjectForEntityForName:@"Message" inManagedObjectContext:context];
[message setValue:postView.titleTextField.text forKey:@"title"];
[message setValue:postView.contentTextField.text forKey:@"content"];
NSArray *images = @[@"2", @"3", @"4"];
int arc = arc4random()%images.count;
UserInfo *info = [NSEntityDescription insertNewObjectForEntityForName:@"UserInfo" inManagedObjectContext:context];
[info setValue:images[arc] forKey:@"name"];
[info setValue:@(19+arc) forKey:@"age"];
UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:@"%@", images[arc]]]; // 将字符串 转换成 data 类型
[info setValue:UIImagePNGRepresentation(image) forKey:@"headerImage"];
[info setValue:message forKey:@"message"];
// 保存数据
[[AppDelegate appDelegate] saveContext];
[self loadData];
}
// 加载数据
- (void)loadData {
// 读取coreData
// 1、读取managedObjectModel
// 2、找到里面所有实体的名字[model entitiesByName]
// 3、找到要读取的实体NSEntityDescription *entry = entryDic[@"UserInfo"];
// 4、初始化 查询对象 NSFetchRequest *request = [[NSFetchRequest alloc]init];
// 5、通过上下文 查找 NSArray *list = [context executeFetchRequest:request error:nil];
//
NSManagedObjectContext *context = [[AppDelegate appDelegate] managedObjectContext];
// 1、读取managedObjectModel
NSManagedObjectModel *model = [[AppDelegate appDelegate] managedObjectModel];
// 2、找到里面所有实体的名字[model entitiesByName];
NSDictionary *entitiesDic = [model entitiesByName];
// 3、找到要读取的实体 NSEntityDescription *entry = entryDic[@"UserInfo"];
NSEntityDescription *entity = entitiesDic[@"UserInfo"];
// 4、初始化 查询请求对象 NSFetchRequest
NSFetchRequest *request = [[NSFetchRequest alloc] init];
request.entity = entity;
// 5、通过上下文开始查询
dataList = [context executeFetchRequest:request error:nil];
NSLog(@"dataList is %@", dataList);
if (dataList.count != 0) {
[showView reloadData];
}
}
// 列表内容
- (void)addShowView {
showView = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame)-64) style:UITableViewStylePlain];
showView.delegate = self;
showView.dataSource = self;
[self.view addSubview:showView];
}
#pragma mark - tableView 代理方法
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return dataList.count;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return 100;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *cellId = @"id";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellId];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellId];
}
UserInfo *info = dataList[indexPath.row];
cell.imageView.image = [UIImage imageWithData:info.headerImage];
cell.textLabel.text = info.name;
Message *message = info.message;
cell.detailTextLabel.text = message.title;
return cell;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
/ PostView.h
// UI-NO-42-1 CoreData-1
//
// Created by on 15/10/5.
//
#import <UIKit/UIKit.h>
@interface PostView : UIView
@property (nonatomic, retain)UITextField *titleTextField;
@property (nonatomic, retain)UITextView *contentTextField;
@end
//
// PostView.m
// UI-NO-42-1 CoreData-1
//
// Created by 容伟 on 15/10/5.
// Copyright (c) 2015年 容伟. All rights reserved.
//
#import "PostView.h"
@implementation PostView
- (instancetype)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
self.backgroundColor = [UIColor brownColor];
self.titleTextField = [[UITextField alloc] initWithFrame:CGRectMake(10, 100, CGRectGetWidth([UIScreen mainScreen].bounds)-20, 40)];
self.titleTextField.placeholder = @"请输入标题,在下面输入框输入内容";
self.titleTextField.borderStyle = UITextBorderStyleRoundedRect;
[self addSubview:self.titleTextField];
self.contentTextField = [[UITextView alloc] initWithFrame:CGRectMake(10, CGRectGetMaxY(self.titleTextField.frame)+10, CGRectGetWidth([UIScreen mainScreen].bounds)-20, 200)];
self.contentTextField.layer.cornerRadius = 5;
self.contentTextField.layer.borderColor = [UIColor grayColor].CGColor;
self.contentTextField.layer.borderWidth = 1;
[self addSubview:self.contentTextField];
}
return self;
}
@end
