安卓期末大作业-图书馆借书系统、图书借阅app源码（高分项目）

package com.xkx.book.database; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import com.xkx.book.enity.User; import java.util.ArrayList; import java.util.List; public class UserDBHelper extends SQLiteOpenHelper { private static final String DB_NAME = "user.db"; private static final String TABLE_NAME = "user_info"; private static final int DB_VERSION = 1; private static UserDBHelper mHelper = null; private SQLiteDatabase mRDB = null; private SQLiteDatabase mWDB = null; private UserDBHelper(Context context) { super(context, DB_NAME, null, DB_VERSION); } //利用单例模式获取数据库帮助器的唯一实例 public static UserDBHelper getInstance(Context context) { if (mHelper == null) { mHelper = new UserDBHelper(context); } return mHelper; } // 创建数据库，执行建表语句 @Override public void onCreate(SQLiteDatabase db) { String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME + " (" + "_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL," + " userid INTEGER not null," + " username varchar not null," + " password LONG not null," + " is_book INTEGER not null," + " user_status INTEGER not null," + " is_deleted INTEGER not null);"; db.execSQL(sql); db.execSQL("insert into " + TABLE_NAME + "(userid,username,password,is_book,user_status,is_deleted)Values('admin','管理员','1','0','1','0')"); db.execSQL("insert into " + TABLE_NAME + "(userid,username,password,is_book,user_status,is_deleted)Values('1001','用户1001','1','0','0','0')"); } //打开数据库的读连接 public SQLiteDatabase openReadLink() { if (mRDB == null || !mRDB.isOpen()) { mRDB = mHelper.getReadableDatabase(); } return mRDB; } //打开数据库的写连接 public SQLiteDatabase openWriteLink() { if (mWDB == null || !mWDB.isOpen()) { mWDB = mHelper.getWritableDatabase(); } return mWDB; } //关闭数据库连接 public void closeLink() { if (mRDB != null && mRDB.isOpen()) { mRDB.close(); mRDB = null; } if (mWDB != null && mWDB.isOpen()) { mWDB.close(); mWDB = null; } } @Override public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) { } //添加用户 public long insert(User user) { ContentValues values = new ContentValues(); values.put("userid", user.userid); values.put("username", user.username); values.put("password", user.password); values.put("is_book", user.is_book); values.put("user_status", user.user_status); values.put("is_deleted", user.is_deleted); //执行插入记录动作，该语句返回插入记录的行号 //如果第三个参数values 为null或者元素个数为0，由于insert()方法必须添加一条除了主键之外其它字段 // // //如果第三个参数values 不为null并且元素的个数大于0，可以把第二个参数设置为null return mWDB.insert(TABLE_NAME, null, values); } // 删除用户 public long deleteById(String userid) { //删除所有 // return mWDB.delete(TABLE_NAME, "1=1", null); //按名字删除 return mWDB.delete(TABLE_NAME, "userid=?", new String[]{userid}); } // 修改用户 public long update(User user) { ContentValues values = new ContentValues(); values.put("userid", user.userid); values.put("username", user.username); values.put("password", user.password); values.put("is_book", user.is_book); values.put("user_status", user.user_status); values.put("is_deleted", user.is_deleted); return mWDB.update(TABLE_NAME, values, "userid=?", new String[]{user.userid}); } //查询所有 public List<User> queryAll() { List<User> list = new ArrayList<>(); //执行记录查询动作，该语句返回结果集的游标 Cursor cursor = mRDB.query(TABLE_NAME, null, null, null, null, null, null); //循环游标，取出游标所指的每条记录 while (cursor.moveToNext()) { User user = new User(); user.id = cursor.getInt(0); user.userid = cursor.getString(1); user.username = cursor.getString(2); user.password = cursor.getLong(3); user.is_book = cursor.getInt(4); user.user_status = cursor.getInt(5); user.is_deleted = cursor.getInt(6); list.add(user); } return list; } //按name 查询 public List<User> queryByName(String name) { List<User> list = new ArrayList<>(); //执行记录查询动作，该语句返回结果集的游标 Cursor cursor = mRDB.query(TABLE_NAME, null, "name=?", new String[]{name}, null, null, null); //循环游标，取出游标所指的每条记录 while (cursor.moveToNext()) { User user = new User(); user.id = cursor.getInt(0); user.userid = cursor.getString(1); user.username = cursor.getString(2); user.password = cursor.getLong(3); user.is_book = cursor.getInt(4); user.user_status = cursor.getInt(5); user.is_deleted = cursor.getInt(6); list.add(user); } return list; } //按Uid 查询 public List<User> queryById(String uid) { List<User> list = new ArrayList<>(); //执行记录查询动作，该语句返回结果集的游标 Cursor cursor = mRDB.query(TABLE_NAME, null, "userid=?", new String[]{uid}, null, null, null); //循环游标，取出游标所指的每条记录 while (cursor.moveToNext()) { User user = new User(); user.id = cursor.getInt(0); user.userid = cursor.getString(1); user.username = cursor.getString(2); user.password = cursor.getLong(3); user.is_book = cursor.getInt(4); user.user_status = cursor.getInt(5); user.is_deleted = cursor.getInt(6); list.add(user); } return list; } //按Uid和psw 查询 public List<User> queryByUid(String uid, String psw) { List<User> list = new ArrayList<>(); //执行记录查询动作，该语句返回结果集的游标 Cursor cursor = mRDB.query(TABLE_NAME, null, "userid=? and password=?", new String[]{uid, psw}, null, null, null); //循环游标，取出游标所指的每条记录 while (cursor.moveToNext()) { User user = new User(); user.id = cursor.getInt(0); user.userid = cursor.getString(1); user.username = cursor.getString(2); user.password = cursor.getLong(3); user.is_book = cursor.getInt(4); user.user_status = cursor.getInt(5); user.is_deleted = cursor.getInt(6); list.add(user); } return list; } }