Android studio SQLite数据库存储登录验证

//SQLite数据库存储登录验证
public class LoginActivity extends AppCompatActivity {
    //声明共享存储（全局变量）
    private SharedPreferences spf;
    private SQLiteDatabase db;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        //在打开页面时初始化共享存储对象spf  "users"表名
        spf=getSharedPreferences("users", Context.MODE_PRIVATE);
        //初始化数据库
        MySQLiteOpenHelper sqLiteOpenHelper=new MySQLiteOpenHelper(LoginActivity.this,"users.db",null,1);
        db=sqLiteOpenHelper.getReadableDatabase();
    }

    /**
     * 登录
     * @param view
     */
    public void login(View view) {
        //获取页面视图组件
        EditText accountEt = findViewById(R.id.account);
        EditText passwordEt = findViewById(R.id.password);

        //获取用户名
        String account = accountEt.getText().toString();
        String password = passwordEt.getText().toString();

        //表单验证
        //判断用户名是否为空
        if (account == null || "".equals(account)) {
            showDialog("用户名不能为空!");
            return;
        }
        //判断密码是否为空
        if (password == null || "".equals(password)) {
            showDialog("密码不能为空!");
            return;
        }
        //验证登录，将用户输入的用户名和密码和共享存储里面的内容进行比对
        String sql = "select * from users where account=? and password=?";
        Cursor cursor = db.rawQuery(sql, new String[]{account, password});
        /*if (account.equals(spf.getString("account",""))&&
                password.equals(spf.getString("password",""))){
            showDialog("登录成功！");
            //登录成功后跳转到首页
            Intent intent=new Intent(LoginActivity.this,HomeActivity.class);
            //传递登录成功的用户名
            intent.putExtra("account",account);
            startActivity(intent);
        }else{
            showDialog("用户名或密码输入错误！");
        }*/
        if (cursor.moveToFirst()) {
            //showDialog("登录成功！");
            Toast.makeText(LoginActivity.this, "登录成功！", Toast.LENGTH_SHORT).show();
            //登录成功后跳转到首页
            Intent intent = new Intent(LoginActivity.this, HomeActivity.class);
            //传递登录成功的用户名
            intent.putExtra("account", account);
            startActivity(intent);
        } else {
            showDialog("用户名或密码输入错误！");
        }
    }

    //设置提示框
    public void showDialog(String msg){
        //1、创建AlertDialog.Builder对象
        AlertDialog.Builder builder=new AlertDialog.Builder(LoginActivity.this);
        //2、设置提示窗口相关信息
        builder.setTitle("提示");
        builder.setMessage(msg);//提示信息
        builder.setPositiveButton("确认", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {

            }
        });
        builder.setCancelable(false);//点击空白区域不能被关掉  true能被关掉
        builder.show();//显示提示框
    }
}

public class MySQLiteOpenHelper extends SQLiteOpenHelper {
    /**
     * 构造函数
     * @param context
     * @param name
     * @param factory
     * @param version
     */
    public MySQLiteOpenHelper(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {
        super(context, name, factory, version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        //创建数据库
        String sql="create table users (" +
                "id integer primary key autoincrement," +
                "account text," +
                "password text)";
        db.execSQL(sql);
        //插入一条数据
        String sql2="insert into users (account,password) values ('admin','123')";
        db.execSQL(sql2);

    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

    }
}