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基于iOS Realm数据库的使用实例详解
类别:IOS编程/Objective-C   作者:码皇   来源:互联网   点击:

下面小编就为大家分享一篇基于iOS Realm数据库的使用实例详解,具有很好的参考价值,希望对大家有所帮助。一起跟随小编过来看看吧

首先下载Realm源代码,https://realm.io/cn/docs/objc/latest

将下载的文件解压,从 ios/static/ 目录中将 Realm.framework 拖曳到 Xcode 工程的文件导航器内,然后在 Xcode 文件导航器中选中工程。然后选择应用目标,前往 Build Phases 选项卡。在 Link Binary with Libraries 部分中单击 + 按钮,然后添加 libc++.tbd 和 libz.tbd。这样还没有完,我们还需要安装插件,打开解压文件夹下的plugin,运行RealmPlugin.xcodeproj,然后重启XCode。

这样环境配置就完了,现在说重点如何去使用。

1.创建实体类

new File翻到最下面点击创建Realm实体类

    #import <Realm/Realm.h>@interface TestBean : RLMObject@property NSString* name;
    @property NSInteger age;
    @end// This protocol enables typed collections. i.e.:// RLMArray<TestBean *><TestBean>RLM_ARRAY_TYPE(TestBean)#import "TestBean.h"@implementation TestBean@end

2.增删改查

这个增加,可以看到直接添加实体类就行了,这个RLMRealm就是数据库的操作类,以后所有操作都靠他。

    -(void)addAction{
    NSLog(@"add");
    self.name = _tf_name.text;
    self.age = [_tf_age.text integerValue];
    TestBean* bean = [[TestBean alloc]init];
    bean.name = self.name;
    bean.age = self.age;
    RLMRealm *realm = [RLMRealm defaultRealm];
    [realm transactionWithBlock:^{
    [realm addObject:bean];
    }
    ];
    }

删除也是通过删除实体类来实现,但是我们需要首先通过查询出实体类才行。这个查询我们可以看到通过我们创建的实体类就能实现

    -(void)deleteAction{
    NSLog(@"delete");
    RLMResults *dogs = [TestBean allObjects];
    RLMRealm *realm = [RLMRealm defaultRealm];
    [realm transactionWithBlock:^{
    for (TestBean *bean in dogs) {
    [realm deleteObject:bean];
    }
    }
    ];
    }

更新也是通过改变实体类的数据来实现

    -(void)updateAction{
    NSLog(@"update");
    RLMResults *dogs = [TestBean allObjects];
    [[RLMRealm defaultRealm] transactionWithBlock:^{
    for (TestBean *bean in dogs) {
    bean.name = @"李四";
    }
    }
    ];
    }

查询我们还可以添加条件

    // 使用断言字符串来查询RLMResults<Dog *> *tanDogs = [Dog objectsWhere:@"color = 'tan' AND name BEGINSWITH 'B'"];
    // 使用 NSPredicate 来查询NSPredicate *pred = [NSPredicate predicateWithFormat:@"color = %@ AND name BEGINSWITH %@", @"tan", @"B"];
    tanDogs = [Dog objectsWithPredicate:pred];

3.排序

这个是在查询完后去实现,通过实体类的key来排序。

    -(void)sortAction{
    NSLog(@"query");
    RLMResults *dogs = [[TestBean allObjects] sortedResultsUsingKeyPath:@"name" ascending:YES];
    [[RLMRealm defaultRealm] transactionWithBlock:^{
    for (TestBean *bean in dogs) {
    NSLog(@"%@",bean.name);
    }
    }
    ];
    }

4.小结

只说了常用的功能,贴上官方中文文档供大家参考

https://realm.io/cn/docs/objc/latest

5.例子代码

    //// ViewController.m// BmobTest//// Created by shanreal-iOS on 2017/12/9.// Copyright ©
    2017年 shanreal.LongZhenHao. All rights reserved.//#import "ViewController.h"#import "TestBean.h"@interface ViewController ()@property(nonatomic,strong)UIButton* add;
    @property(nonatomic,strong)UIButton* delete;
    @property(nonatomic,strong)UIButton* update;
    @property(nonatomic,strong)UIButton* query;
    @property(nonatomic,strong)UIButton* sort;
    @property(nonatomic,strong)NSString* name;
    @property(nonatomic,assign)NSInteger* age;
    @property(nonatomic,strong)UITextField* tf_name;
    @property(nonatomic,strong)UITextField* tf_age;
    @end@implementation ViewController- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib. _add = [[UIButton alloc]initWithFrame:CGRectMake(10, 30, 100, 20)];
    [_add setTitle:@"add" forState:UIControlStateNormal];
    [_add setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [_add addTarget:self action:@selector(addAction) forControlEvents:UIControlEventTouchUpInside];
    _delete = [[UIButton alloc]initWithFrame:CGRectMake(10, 60, 100, 20)];
    [_delete setTitle:@"delete" forState:UIControlStateNormal];
    [_delete setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [_delete addTarget:self action:@selector(deleteAction) forControlEvents:UIControlEventTouchUpInside];
    _update = [[UIButton alloc]initWithFrame:CGRectMake(10, 90, 100, 20)];
    [_update setTitle:@"update" forState:UIControlStateNormal];
    [_update setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [_update addTarget:self action:@selector(updateAction) forControlEvents:UIControlEventTouchUpInside];
    _query = [[UIButton alloc]initWithFrame:CGRectMake(10, 120, 100, 20)];
    [_query setTitle:@"query" forState:UIControlStateNormal];
    [_query setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [_query addTarget:self action:@selector(queryAction) forControlEvents:UIControlEventTouchUpInside];
    _sort = [[UIButton alloc]initWithFrame:CGRectMake(10, 150, 100, 20)];
    [_sort setTitle:@"sort" forState:UIControlStateNormal];
    [_sort setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [_sort addTarget:self action:@selector(sortAction) forControlEvents:UIControlEventTouchUpInside];
    _tf_name = [[UITextField alloc]initWithFrame:CGRectMake(50, 300, 200, 20)];
    _tf_name.placeholder=@"name";
    _tf_age = [[UITextField alloc]initWithFrame:CGRectMake(50, 350, 200, 20)];
    _tf_age.placeholder=@"age";
    [self.view addSubview:_add];
    [self.view addSubview:_delete];
    [self.view addSubview:_update];
    [self.view addSubview:_query];
    [self.view addSubview:_sort];
    [self.view addSubview:_tf_name];
    [self.view addSubview:_tf_age];
    }
    -(void)addAction{
    NSLog(@"add");
    self.name = _tf_name.text;
    self.age = [_tf_age.text integerValue];
    TestBean* bean = [[TestBean alloc]init];
    bean.name = self.name;
    bean.age = self.age;
    RLMRealm *realm = [RLMRealm defaultRealm];
    [realm transactionWithBlock:^{
    [realm addObject:bean];
    }
    ];
    }
    -(void)deleteAction{
    NSLog(@"delete");
    RLMResults *dogs = [TestBean allObjects];
    RLMRealm *realm = [RLMRealm defaultRealm];
    [realm transactionWithBlock:^{
    for (TestBean *bean in dogs) {
    [realm deleteObject:bean];
    }
    }
    ];
    }
    -(void)updateAction{
    NSLog(@"update");
    RLMResults *dogs = [TestBean allObjects];
    [[RLMRealm defaultRealm] transactionWithBlock:^{
    for (TestBean *bean in dogs) {
    bean.name = @"李四";
    }
    }
    ];
    }
    -(void)queryAction{
    NSLog(@"query");
    RLMResults *dogs = [TestBean allObjects];
    [[RLMRealm defaultRealm] transactionWithBlock:^{
    for (TestBean *bean in dogs) {
    NSLog(@"%@",bean.name);
    }
    }
    ];
    }
    -(void)sortAction{
    NSLog(@"query");
    RLMResults *dogs = [[TestBean allObjects] sortedResultsUsingKeyPath:@"name" ascending:YES];
    [[RLMRealm defaultRealm] transactionWithBlock:^{
    for (TestBean *bean in dogs) {
    NSLog(@"%@",bean.name);
    }
    }
    ];
    }
    - (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.}
    @end

以上这篇基于iOS Realm数据库的使用实例详解就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持脚本之家。

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