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好久没来了，因为平时都记在云笔记里，偶然想起51自己早期有写博客，不忘初心，今天来这留一篇吧，最近项目需要写数据库，所以这边对greendao做一些记录，也加深学习。
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配置android studio 和导入green到库
project的gradle
repositories {
jcenter()
mavenCentral() // add repository
}
dependencies {
classpath 'org.greenrobot:greendao-gradle-plugin:3.2.2' // add plugin
}module的gradle
apply plugin: 'com.android.application'
apply plugin: 'org.greenrobot.greendao' // apply plugin
android {
compileSdkVersion 25
buildToolsVersion "25.0.2"
greendao {
schemaVersion 1
targetGenDir 'src/main/java'
}
defaultConfig {
applicationId "com.example.mygreendao"
minSdkVersion 15
targetSdkVersion 25
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:25.2.0'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
testCompile 'junit:junit:4.12'
compile 'org.greenrobot:greendao:3.2.2' // add library
}
吐槽一下，51cto的博客是真的踏马不人性化，直接这写了。
建立一个bean，这写为UUser，写完rebuild gradle ，会自动生成DaoMaster，Daosession，UUserDao（你实体
对应的Dao）
@Entity
public class UUser {
String name;
int age;
@Id
private Long id;//默认自增长，修改数据需要这个key，不然报错
@Generated(hash = 1431141183)
public UUser(String name, int age, Long id) {
this.name = name;
this.age = age;
this.id = id;
}
@Generated(hash = 751422734)
public UUser() {
}
set，get方法忽略
}
建立一个DBManager
public class DBManager {
private final static String dbName = "test_db";
private static DBManager mInstance;
private DaoMaster.DevOpenHelper openHelper;
private Context context;
public DBManager(Context context) {
this.context = context;
openHelper = new DaoMaster.DevOpenHelper(context, dbName, null);
}
/**
* 获取单例引用
*
* @param context
* @return
*/
public static DBManager getInstance(Context context) {
if (mInstance == null) {
synchronized (DBManager.class) {
if (mInstance == null) {
mInstance = new DBManager(context);
}
}
}
return mInstance;
}
/**
* 获取可读数据库
*/
private SQLiteDatabase getReadableDatabase() {
if (openHelper == null) {
openHelper = new DaoMaster.DevOpenHelper(context, dbName, null);
}
SQLiteDatabase db = openHelper.getReadableDatabase();
return db;
}
/**
* 获取可写数据库
*/
private SQLiteDatabase getWritableDatabase() {
if (openHelper == null) {
openHelper = new DaoMaster.DevOpenHelper(context, dbName, null);
}
SQLiteDatabase db = openHelper.getWritableDatabase();
return db;
}
private DaoSession geWriteDaoSession() {
DaoMaster daoMaster = new DaoMaster(getWritableDatabase());
DaoSession daoSession = daoMaster.newSession();
return daoSession;
}
private DaoSession geReadDaoSession() {
DaoMaster daoMaster = new DaoMaster(getReadableDatabase());
DaoSession daoSession = daoMaster.newSession();
return daoSession;
}
/**
* UUser
* 插入一条记录
*
* @param user
*/
public void insertUser(UUser user) {
UUserDao userDao = geWriteDaoSession().getUUserDao();
userDao.insert(user);
}
/**
* UUser
* 删除一条记录
*
* @param user
*/
public void deleteUser(UUser user) {
UUserDao userDao = geWriteDaoSession().getUUserDao();
userDao.delete(user);
}
/**
* UUser
* 更改一条记录
*
* @param user
*/
public void updateUser(UUser user) {
UUserDao userDao = geWriteDaoSession().getUUserDao();
userDao.update(user);
}
/**
* 查询用户列表
*/
public List queryUserList() {
UUserDao userDao = geReadDaoSession().getUUserDao();
QueryBuilder qb = userDao.queryBuilder();
List list = qb.list();
return list;
}
}
好懒啊，哎。