GreenDao的增刪改查語句
阿新 • • 發佈:2018-12-09
首先編寫一個MyApplication類繼承Application類 package com.example.sean.greendaotest_2;
import android.app.Application; import android.database.sqlite.SQLiteDatabase;
import GreenDao.greendao.db.DaoMaster; import GreenDao.greendao.db.DaoSession;
public class MyApplication extends Application { private DaoMaster.DevOpenHelper mHelper; private SQLiteDatabase db; private DaoMaster mDaoMaster; private DaoSession mDaoSession;
//靜態單例 public static MyApplication instances; @Override public void onCreate() { super.onCreate(); instances = this; setDatabase(); } public static MyApplication getInstances(){ return instances; } /** * 設定greenDao */ private void setDatabase() { mDaoMaster = new DaoMaster(db); mDaoSession = mDaoMaster.newSession(); } public DaoSession getDaoSession() { return mDaoSession; } public SQLiteDatabase getDb() { return db; }
}
我將其對資料庫的操作封裝到了一個Util類裡面,具體程式碼如下:
package com.example.sean.greendaotest_2;
import java.util.List;
import GreenDao.greendao.db.UserDao;
/* * 資料庫增刪改查工具類 * */ public class DaoUtil { private UserDao userDao;
/* * 增加資料 * */ public void addUser(String name, int age) { userDao = MyApplication.getInstances().getDaoSession().getUserDao(); User user = new User(); user.setAge(age); user.setName(name); userDao.insertOrReplace(user); } /* * 刪除資料,通過Key刪除 * */ public void deleteUser(long id) { userDao = MyApplication.getInstances().getDaoSession().getUserDao(); userDao.deleteByKey(id); } /* * 查詢資料 * */ public String[] queryUser() { //StringBuilder sb = new StringBuilder(); userDao = MyApplication.getInstances().getDaoSession().getUserDao(); List<User> userList = userDao.loadAll(); String[] temp = new String[userList.size()]; for (int i = 0; i < userList.size(); i++) { /* String temp = ""; temp += "ID = " + userList.get(i).getId(); temp += "Name = " + userList.get(i).getName(); temp += "Age = " + userList.get(i).getAge(); sb.append(temp);*/ temp[i] += "ID = " + userList.get(i).getId(); temp[i] += "NAME = " + userList.get(i).getName(); temp[i] += "AGE = " + userList.get(i).getAge(); } return temp; } /* * 修改資料 * */ public void updateUser(String name, int age, long id) { userDao = MyApplication.getInstances().getDaoSession().getUserDao(); User user = new User(); user.setId(id); //根據Id來查詢到資料,並且修改資料 user.setAge(age); user.setName(name); userDao.update(user); }
} 關於GreenDao的配置,可以檢視我的其他博文,以上就是GreenDao的簡單使用,如有不足,請多指教。