如何从android中的sql server db中检索数据

Question

这是我第一次开发安卓应用程序。我想将一些数据与文本框中提供的基于网格视图或列表视图的员工 ID 绑定。我怎样才能做到这一点。请帮助我找到合适的解决方案。谢谢。

ConnectionClass.java：

 import android.annotation.SuppressLint;
 import android.os.StrictMode;
 import android.util.Log;
 import java.sql.SQLException;
 import java.sql.Connection;
 import java.sql.DriverManager;

/**
 * Created by H-PC on 16-Oct-15.
 */
public class ConnectionClass {

    String ip = "******";
    String classs = "net.sourceforge.jtds.jdbc.Driver";
    String db = "IDB";
    String un = "sa";
    String password = "admin123";

    @SuppressLint("NewApi")
    public Connection CONN() {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
                .permitAll().build();
        StrictMode.setThreadPolicy(policy);
        Connection conn = null;
        String ConnURL = null;
        try {

            Class.forName(classs);
            ConnURL = "jdbc:jtds:sqlserver://" + ip + ";"
                    + "databaseName=" + db + ";user=" + un + ";password="
                    + password + ";";
            conn = DriverManager.getConnection(ConnURL);
        } catch (SQLException se) {
            Log.e("ERRO", se.getMessage());
        } catch (ClassNotFoundException e) {
            Log.e("ERRO", e.getMessage());
        } catch (Exception e) {
            Log.e("ERRO", e.getMessage());
        }
        return conn;
    }
}

-------------------------------------------------------------------------------

MainActivity.java：

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.view.View.OnClickListener;
import java.sql.Connection;

public class MainActivity extends AppCompatActivity {

    Button button1;
    TextView txtView1;
    EditText editText1;
    ConnectionClass connectionClass;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        connectionClass = new ConnectionClass();
        button1=(Button)findViewById(R.id.btnSearch);
        txtView1=(TextView)findViewById(R.id.searchLbl);
        editText1=(EditText)findViewById(R.id.txtSearch);

        button1.setOnClickListener(new View.OnClickListener(){

        @Override
        public void onClick(View v) {

                String newValue = editText1.getText().toString().trim();

                if (newValue.toString().trim().equals("")) {
                    txtView1.setText("Please Enter ID");
                }
                else
                {
                    Connection con = connectionClass.CONN();

                if(con==null)
                {
                    String msg="Error in SQL Connection";
                }
                else
                {
                    String query= "Select * From Employees Where EmpId='"+newValue+"'";
                }
                }
            }


        });
        }
    }

---------------------------------------------------------------------------

文字

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.example.laptop37.myapplication2.MainActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <RelativeLayout
            android:orientation="horizontal"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true">



            <EditText
                android:layout_width="285dp"
                android:layout_height="42dp"
                android:id="@+id/txtSearch"
                android:layout_weight="1"
                android:textColor="@color/material_deep_teal_500"
                android:hint="enter id"
                android:layout_gravity="center_vertical"
                android:layout_below="@+id/textHeading"
                android:layout_alignParentLeft="true"
                android:layout_alignParentStart="true"
                android:layout_marginTop="30px"
                android:background="#b1e1b1"
                android:layout_marginLeft="10px"
                />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textAppearance="?android:attr/textAppearanceLarge"
                android:text="Employee Data"
                android:id="@+id/textHeading"
                android:layout_weight="1"
                android:layout_alignParentTop="true"
                android:layout_alignParentLeft="true"
                android:layout_alignParentStart="true"
                android:layout_marginTop="30px"
                android:layout_alignParentRight="true"
                android:layout_alignParentEnd="true"
                android:textAlignment="center"
                android:textColor="#2eb114"
                android:textSize="70px"
                />

            <Button
                android:layout_width="85dp"
                android:layout_height="42dp"
                android:text="Search"
                android:id="@+id/btnSearch"
                android:layout_weight="0.43"
                android:background="@color/background_material_dark"
                android:textColor="#ffffff"
                android:layout_gravity="center_vertical"
                android:layout_alignBottom="@+id/txtSearch"
                android:layout_toRightOf="@+id/txtSearch"
                android:layout_toEndOf="@+id/txtSearch"
                android:layout_marginLeft="10px"
                android:layout_marginStart="10px"
                android:layout_marginRight="10px"
                />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/searchLbl"
                android:layout_below="@+id/txtSearch"
                android:layout_alignLeft="@+id/txtSearch"
                android:layout_alignStart="@+id/txtSearch"
                android:layout_marginTop="64dp" />

            <GridView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/gridViewEmp"
                android:layout_alignRight="@+id/txtSearch"
                android:layout_alignEnd="@+id/txtSearch"
                android:layout_below="@+id/txtSearch" />


        </RelativeLayout>
    </RelativeLayout>

</android.support.design.widget.CoordinatorLayout>
-------------------------------------------------------------------------------

表（员工）：

EmpId EmpName Designation Gender Age Mob Address
----- ------- ----------- ------ --- --- -------
1      asd    ttt           M     30     fghfhfh
2      dfg    yyy           F     26     fhgfhfhf
3      dfhh   ppp           M     47     fghhfghf

--------------------------------------------------------------------------------

设计：

Answer 1

你不能直接访问sql server ...

首先你需要做一个网络服务，因为你的数据库在你的主机上而不是在你的手机内存卡上，网络服务处理来自应用程序的请求并做出相应的响应。也就是说，你从应用程序传递一些 SQL 查询参数到网络服务并让您的 Web 服务处理请求。 此 Web 服务可以是任何类型的 JAVA、PHP 等。 您只需要使用标准的 HTTP 方法。 click

Answer 2

这是一个示例，说明如何将从数据库收集的数据显示到列表视图中。

    final ListView listView = getListView();
    final String[][] _customerData = MySQL.Get("SELECT Id,Name,Surname FROM customers");
    final List<Integer> _currentCustomerIDs = new ArrayList<>();
    final List<String> _nameList = new ArrayList<>();

    for (String[] customer : _customerData)
    {
        _currentCustomerIDs.add(Integer.valueOf(customer[0]));
        _nameList.add(customer[2] + " " + customer[1]);
    }
    listView.invalidateViews();
    listView.setTextFilterEnabled(true);
    listView.setAdapter(getListAdapter());
    setListAdapter(new ArrayAdapter<>(this, R.layout.customer_list, _nameList.toArray()));

您需要进行选择查询， 然后声明一个整数列表， 遍历该列表， 将其添加到您的数组列表中， 最后将其添加到您的列表视图中。

上面是一个示例，使用从 jdbc 数据库收集的数据将整数和字符串添加到列表中。

祝你好运，希望对你有帮助！

Answer 3

在这种情况下你

button1.setOnClickListener(new View.OnClickListener(){

    @Override
    public void onClick(View v) {

            String newValue = editText1.getText().toString().trim();

            if (newValue.toString().trim().equals("")) {
                txtView1.setText("Please Enter ID");
            }
            else
            {
                Connection con = connectionClass.CONN();

                if(con==null)
                {
                    String msg="Error in SQL Connection";
                }
                else
                {

                    try {

                        st = con.createStatement();

                        // set the result in result set then fetch it
                        rs = st.executeQuery("Select * From Employees Where EmpId='"+newValue+"'");

                        if (rs.next()){
                            Toast.makeText(getApplicationContext()," EmpId :. " + rs.getString("EmpId")+" EmpName :. "+rs.getString("EmpName")+ " Designation :. " + rs.getString("Designation")+" Gender :. "+rs.getString("Gender")+" etc..",LENGTH_LONG).show();

                        }else{
                            // you have no record

                        }


                    }
                }
            }


    });
});