coreDate 简化版

建表：

自动生成：

代码：

//
//  RootViewController.m
//  coreDate 简化版
#import "RootViewController.h"
#import "entity.h"
#import "AppDelegate.h"
@interface RootViewController ()
{
    UILabel *label;
    NSInteger number;
    NSDictionary *Dic;
    NSMutableArray *arr;
    UILabel *age;
    BOOL isFirst;
}
@end

@implementation RootViewController


- (void)viewDidLoad {
    [super viewDidLoad];
    isFirst=NO;
    
    Dic=[[NSDictionary alloc]initWithObjectsAndKeys:@"one",@"1",@"two",@"2", nil];
    arr=[NSMutableArray arrayWithObjects:@"少年",@"青年",@"老年", nil];
    number=1;
    label=[[UILabel alloc]initWithFrame:CGRectMake(50, 100, 100,100)];
    label.font=[UIFont systemFontOfSize:12];
    label.textAlignment=NSTextAlignmentCenter;
    label.text=@"test";
    label.tag=1;
    label.backgroundColor=[UIColor cyanColor];
    
    age=[[UILabel alloc]initWithFrame:CGRectMake(200, 100, 100,100)];
    age.font=[UIFont systemFontOfSize:12];
    age.textAlignment=NSTextAlignmentCenter;
    age.text=@"25";
    age.tag=2;
    age.backgroundColor=[UIColor cyanColor];
    
    [self insertCoreData];
    [self dataFetchRequest];
    UIButton *btn=[UIButton buttonWithType:UIButtonTypeCustom];
    btn.frame=CGRectMake(50, 230, 100, 100);
    [btn setTitle:@"删除" forState:UIControlStateNormal];
    btn.backgroundColor=[UIColor purpleColor];
    [btn addTarget:self action:@selector(delete) forControlEvents:UIControlEventTouchUpInside];
    
    UIButton *btn1=[UIButton buttonWithType:UIButtonTypeCustom];
    btn1.frame=CGRectMake(50, 340, 100, 100);
    [btn1 setTitle:@"查找" forState:UIControlStateNormal];
    btn1.backgroundColor=[UIColor purpleColor];
    [btn1 addTarget:self action:@selector(seek) forControlEvents:UIControlEventTouchUpInside];
    UIButton *btn2=[UIButton buttonWithType:UIButtonTypeCustom];
    btn2.frame=CGRectMake(50, 450, 100, 100);
    [btn2 setTitle:@"增加" forState:UIControlStateNormal];
    btn2.backgroundColor=[UIColor purpleColor];
    [btn2 addTarget:self action:@selector(insertCoreData) forControlEvents:UIControlEventTouchUpInside];
    

    [self.view addSubview:btn1];
    [self.view addSubview:btn];
    [self.view addSubview:btn2];
    [self.view addSubview:label];
    [self.view addSubview:age];
}

-(void)seek
{
    UIApplication * application = [UIApplication sharedApplication];
    //默认appDelegate就是UIApplication的代理
    AppDelegate * delegate = application.delegate;
    NSManagedObjectContext *context = [delegate managedObjectContext];
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *ent = [NSEntityDescription entityForName:@"Entity" inManagedObjectContext:context];
    [fetchRequest setEntity:ent];
    NSError *error;
    NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
    
    if (![fetchedObjects count]) {
        NSLog(@"fetchedObjects 已全部删除");
    }
    
    for (entity *info in fetchedObjects) {
        
        NSLog(@"count:%ld",(unsigned long)[fetchedObjects count]);
        
        //adress字典查找
        NSString *jsonStringDic=[[NSString alloc]initWithFormat:@"%@",info.address];
        //字符串转化成data类型
        NSData *dataDic=[jsonStringDic dataUsingEncoding:NSUTF8StringEncoding];
        NSError *errDic;
        
        //将data类型转化成字典
        id jsonObjectDic = [NSJSONSerialization JSONObjectWithData:dataDic
                                                        options:NSJSONReadingAllowFragments
                                                          error:&errDic];

        //根据key进行查找
        label.text=[jsonObjectDic objectForKey:@"2"];
        //age 数组查找
        NSString *jsonStringArr=[[NSString alloc]initWithFormat:@"%@",info.age];
        NSData *dataArr=[jsonStringArr dataUsingEncoding:NSUTF8StringEncoding];
        NSError *errArr;
        id jsonObjectArr=[NSJSONSerialization JSONObjectWithData:dataArr options:NSJSONReadingAllowFragments error:&errArr];
        age.text=[jsonObjectArr objectAtIndex:2];
        
        
        NSLog(@"***************age.text0=%@",jsonObjectArr[0]);
        NSLog(@"***************age.text1=%@",jsonObjectArr[1]);
        NSLog(@"***************age.text3=%@",jsonObjectArr[2]);

    }
}
-(void)delete
{

    UIApplication * application = [UIApplication sharedApplication];
    //默认appDelegate就是UIApplication的代理
    AppDelegate * delegate = application.delegate;
    NSManagedObjectContext *context = [delegate managedObjectContext];
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *ent = [NSEntityDescription entityForName:@"Entity" inManagedObjectContext:context];
    [fetchRequest setEntity:ent];
    
    NSError *error;
    NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];

    for (entity *info in fetchedObjects) {
        NSLog(@"%@",info);
        //删除  整体都会删除
        [context deleteObject:info];
    }
    number ++;
    //coredata 数据保存
    if ([context save:&error]) {
        //更新成功
        NSLog(@"更新成功");
    }
}

-(void)insertCoreData
{
    if (isFirst) {
        UIApplication * application = [UIApplication sharedApplication];
        //默认appDelegate就是UIApplication的代理
        AppDelegate * delegate = application.delegate;
        NSManagedObjectContext *context = [delegate managedObjectContext];
        
        entity *entity = [NSEntityDescription insertNewObjectForEntityForName:@"Entity" inManagedObjectContext:context];
        
        entity.name = @"test";
        
        NSError *errDic;
        //字典转化成data类型，再转化成string进行保存
        //注意：是 NSData 不是 NSDate(时间)
        NSData *dataDic=[NSJSONSerialization dataWithJSONObject:Dic options:NSJSONWritingPrettyPrinted error:&errDic];
        NSString *jsonString=[[NSString alloc]initWithData:dataDic encoding:NSUTF8StringEncoding];
        
        entity.address=jsonString;
        
        //保存数组
        NSError *errArr;
        NSData *dataArr=[NSJSONSerialization dataWithJSONObject:arr options:NSJSONWritingPrettyPrinted error:&errArr];
        NSString *jsonArr=[[NSString alloc]initWithData:dataArr encoding:NSUTF8StringEncoding];
        
        entity.age=jsonArr;
        
        NSError *error;
        if(![context save:&error])
        {
            NSLog(@"不能保存：%@",[error localizedDescription]);
        }
    }
    else
    {
        isFirst=YES;
    }
}@end