安卓Sqlite数据库

1. package com.example.gentle.hh;

import android.content.Context;
import android.database.DatabaseErrorHandler;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

/**

• Created by Gentle on 2019/10/8.
  */

public class MySqlite extends SQLiteOpenHelper {
private Context context;

public MySqlite(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
    super(context, name, factory, version);
    this.context = context;
}

public MySqlite(Context context, String name, SQLiteDatabase.CursorFactory factory, int version, DatabaseErrorHandler errorHandler) {
    super(context, name, factory, version, errorHandler);
}

@Override
public void onCreate(SQLiteDatabase db) {
    String s = "create table a ("
            + "_id integer primary key autoincrement,"
            + "a varchar (100),"
            + "b varchar (100),"
            + "c varchar (100) "
            + ")";

    db.execSQL(s);
    String sql = "create table person ("
            + "_id integer primary key autoincrement,"
            + "name varchar (100),"
            + "age varchar (100),"
            + "sex varchar (100) "
            + ")";
    db.execSQL(sql);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    String sql = "DROP TABLE IF EXISTS " + "person";
    db.execSQL(sql);
    String sql1 = "DROP TABLE IF EXISTS " + "a";
    db.execSQL(sql1);
  //  if (newVersion > oldVersion)
        onCreate(db);
}

}

package com.example.gentle.hh;

import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
String name,name1;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    MySqlite mySqlite = new MySqlite(this, "ff", null, 14);
    SQLiteDatabase readDB = mySqlite.getReadableDatabase();
    SQLiteDatabase writeDB = mySqlite.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put("name", "这是第二个表单的数据");
    values.put("age", "1");
    values.put("sex", "ma");
    writeDB.insert("person", null, values);
    ContentValues values1 = new ContentValues();
    values1.put("a", "liwei");
    values1.put("b", "18");
    values1.put("c", "man");
    writeDB.insert("a", null, values1);

   /* if (falg == 1) {
        Toast.makeText(this, "成功", Toast.LENGTH_LONG).show();
    } else {
        Toast.makeText(this, "失败", Toast.LENGTH_LONG).show();
    }*/

    // writeDB.close();

 /*   ContentValues values11 = new ContentValues();
    values11.put("name", "ch");
    readDB.update("person", values11, null, null);
    readDB.delete("person",null,null);*/
    String s = "select * from a";
    Cursor cursor = readDB.rawQuery(s, null);
    while (cursor.moveToNext()) {
        name = cursor.getString(cursor.getColumnIndex("a"));
    }

    String ll = "select * from person";
    Cursor cursor1 = readDB.rawQuery(ll, null);
    while (cursor1.moveToNext()) {
        name1 = cursor1.getString(cursor1.getColumnIndex("name"));
    }
    String a = "delete person";
    Toast.makeText(this, "查询结果：" + name, Toast.LENGTH_LONG).show();
    Toast.makeText(this, "查询结果：" + name1, Toast.LENGTH_LONG).show();
    readDB.close();


}

}