加入数据库，以便加入分析

app/src/main/java/com/weihuagu/receiptnotice/DatabaseHelper.java

@@ -0,0 +1,28 @@
+package com.weihuagu.receiptnotice;
+
+import android.content.Context;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+
+import androidx.annotation.Nullable;
+
+public class DatabaseHelper extends SQLiteOpenHelper {
+    //数据库版本号
+    private static Integer Version = 1;
+
+    public DatabaseHelper(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {
+        super(context, name, factory, version);
+    }
+
+    @Override
+    public void onCreate(SQLiteDatabase db) {
+        String sql = "create table plat(id integer primary key autoincrement,name varchar(64),address varchar(64))";
+        db.execSQL(sql);
+
+    }
+
+    @Override
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+
+    }
+}

app/src/main/java/com/weihuagu/receiptnotice/util/DataBaseHolder.java

@@ -0,0 +1,32 @@
+package com.weihuagu.receiptnotice.util;
+
+import android.database.sqlite.SQLiteDatabase;
+
+import com.weihuagu.receiptnotice.DatabaseHelper;
+import com.weihuagu.receiptnotice.MainApplication;
+
+public class DataBaseHolder {
+    //创建 SingleObject 的一个对象
+    private static DataBaseHolder instance = new DataBaseHolder();
+    public DatabaseHelper dbHelper;
+    public SQLiteDatabase sqliteDatabase;
+
+    //让构造函数为 private，这样该类就不会被实例化
+    private DataBaseHolder(){
+        createDataBase();
+    }
+
+    //获取唯一可用的对象
+    public static DataBaseHolder getInstance(){
+        return instance;
+    }
+
+    private void createDataBase(){
+        dbHelper = new DatabaseHelper(MainApplication.getAppContext(),"receiptnotice",null,1);
+        sqliteDatabase = dbHelper.getWritableDatabase();
+    }
+
+    public SQLiteDatabase getDateBase(){
+        return sqliteDatabase;
+    }
+}