java - 从 SQL Server 检索与 Android Studio 中的 Edittext 值相对应的数据

Question

我遇到一个问题，即我的 sql 查询无法根据 Edittext(txt_Id) 中设置的值从 MSSQL 检索特定用户数据。应用程序可以显示我的 txt_Id 值，但无法从数据库中检索与该值相对应的数据。如果我错过了什么，请帮助并通知我。

package com.example.myapplication;

import android.app.Activity;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.Html;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

import com.google.zxing.integration.android.IntentIntegrator;
import com.google.zxing.integration.android.IntentResult;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.HashMap;
import java.util.Locale;
import java.lang.String;

public class Operation extends AppCompatActivity {


    ConnectionClass connectionClass;
    EditText txt_MO,txt_Material,txt_Machine,txt_PFNO, txt_pic, txt_Id;

    Button btn_start;
    ProgressBar pbbar;
    TextView lblName;
    UserSessionManager session;
    Button btn_logout;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_operation);

        session = new UserSessionManager(getApplicationContext());
        EditText txt_Id = (EditText) findViewById(R.id.txt_Id);
//        btn_logout = (Button) findViewById(R.id.btn_logout);
        Toast.makeText(getApplicationContext(),
                "User Login Status: " + session.isUserLoggedIn(),
                Toast.LENGTH_LONG).show();




        // Check user login (this is the important point)
        // If User is not logged in , This will redirect user to LoginActivity
        // and finish current activity from activity stack.
        if(session.checkLogin())
            finish();

        // get user data from session
        HashMap<String, String> user = session.getUserDetails();

        // get name

        String pfno = user.get(UserSessionManager.KEY_PF);
        // get email
        String email = user.get(UserSessionManager.KEY_EMAIL);

        // Show user data on activity
        txt_Id.setText(Html.fromHtml("Name: <b>" + pfno + "</b>"));

//        btn_logout.setOnClickListener(new View.OnClickListener() {
//
//            @Override
//            public void onClick(View arg0) {
//
//                // Clear the User session data
//                // and redirect user to LoginActivity
//                session.logoutUser();
//            }
//        });

        connectionClass = new ConnectionClass();
        txt_MO = (EditText) findViewById(R.id.txt_MO);
        txt_Material = (EditText) findViewById(R.id.txt_Material);
        txt_Machine = (EditText) findViewById(R.id.txt_Machine);
        txt_PFNO = (EditText) findViewById(R.id.txt_PFNO);
        btn_start = (Button) findViewById(R.id.btn_start);
        txt_pic = (EditText) findViewById(R.id.txt_pic);





        btn_start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                AddPro addPro = new AddPro();
                addPro.execute("");

            }
        });

        Button Back = (Button) findViewById(R.id.btn_back);
        Back.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(Operation.this, AddProducts.class);


                startActivity(intent);
            }

        });

        Button ScanMe  = (Button) findViewById(R.id.btn_scan);
        ScanMe.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startQRScanner();
            }
        });
    }



    private void startQRScanner() {

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        IntentResult result =   IntentIntegrator.parseActivityResult(requestCode, resultCode, data);            if (result != null) {
        if (result.getContents() == null) {
            Toast.makeText(this,    "Cancelled",Toast.LENGTH_LONG).show();
        } else {
            updateText(result.getContents());
        }
    } else {
        super.onActivityResult(requestCode, resultCode, data);
    }
    }

    private void updateText(String scanCode) {

        txt_MO.setText(scanCode);
    }


    public class AddPro extends AsyncTask<String, String, String> {



        String z = "";
        Boolean isSuccess = false;


        String MO = txt_MO.getText().toString();
        String Material = txt_Material.getText().toString();
        String Machine = txt_Machine.getText().toString();
        String PFNO  = txt_PFNO.getText().toString();



        @Override
        protected void onPreExecute() {
            //pbbar.setVisibility(View.VISIBLE);
        }

        protected void onPostExecute(String r) {
            //bbar.setVisibility(View.GONE);
            Toast.makeText(Operation.this,r,Toast.LENGTH_SHORT).show();

            if(isSuccess) {
//                Intent i = new Intent(Operation.this, Start_Page.class);
//                startActivity(i);
//                finish();


            }

        }
        protected String doInBackground(String... params) {

            try {
                Connection con = connectionClass.CONN();
                if (con == null) {
                    z = "Error in connection with SQL server";
                } else {
                    String query = "select * from Employee where Id='"+ txt_Id +"' ";
                    Statement stmt = con.createStatement();
                    ResultSet rs = stmt.executeQuery(query);
                    System.out.println(rs.getString(1));
                    if(rs.next())
                    {

txt_pic.setText(Html.fromHtml(rs.getString("Name")));

                        z = "Success";
                        isSuccess=true;


                    }
                    else
                    {
                        z = "wrong";
                        isSuccess = false;
                    }

                }
            }
            catch (Exception ex)
            {
                isSuccess = false;
                z = "Exceptions";
            }

            return z;

    }





    }



}

我希望数据库中的值显示到另一个 Edittext 名称 txt_pic

Answer 1

您正在尝试从后台线程 doInBackground 访问 UI 组件 txt_pic，这是不允许的。您必须从主线程设置文本。

尝试从 doInBackground 传递 rs.getString("Name")，如下所示:

protected String doInBackground(String... params) {

    String result = null;

    try {
        Connection con = connectionClass.CONN();
        if (con == null) {
            z = "Error in connection with SQL server";
        } else {
            String query = "select * from Employee where Id='"+ txt_Id +"' ";
            Statement stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery(query);
            System.out.println(rs.getString(1));
            if(rs.next())
            {

                result = rs.getString("Name");

                z = "Success";
                isSuccess=true;


            }
            else
            {
                z = "wrong";
                isSuccess = false;
            }

        }
    }
    catch (Exception ex)
    {
        isSuccess = false;
        z = "Exceptions";
    }

    return result;

}

然后尝试从onPostExecute进行设置。检查以下内容:

protected void onPostExecute(String r) {
    //bbar.setVisibility(View.GONE);
    Toast.makeText(Operation.this,z,Toast.LENGTH_SHORT).show();

    if(r != null)
        txt_pic.setText(Html.fromHtml(r));

    if(isSuccess) {
        // Intent i = new Intent(Operation.this, Start_Page.class);
        // startActivity(i);
        // finish();


    }

}