安卓Sqlite数据库完成学生管理系统小案例

分别使用sqlite3工具和Android代码的方式建立SQLite数据库。在完成建立数据库的工作后，编程实现基本的数据库操作功能，包括数据的添加、删除和更新，

1. 创建一个学生管理的应用，基本信息包含学生姓名，班级，学号。采用文件存储
   和数据库存储两种方式存储这些信息
2. 应用应该至少包含信息录入和信息显示两个页面
3. 最终生成文件存储和数据库存储两个程序，完成同一个功能。
4. 分析文件存储和数据库存储的异同，以及使用场合

1：先使用sharepreference来完成对数据的存储
接下来直接附上代码

主操作ctivity

package com.example.sharepreferencesave;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import android.app.Activity;
import android.content.Context;
import android.media.MediaMuxer.OutputFormat;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.TextureView;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener{

    private final String fileName = "fileDemo.xml";
    private EditText addSnoEditText,addSnameEditText,addClassEditText;
    private Button btnAdd,btnRead;
    private CheckBox chk;
    private TextView tvShow;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
         btnRead = (Button)findViewById(R.id.btnRead);
         btnAdd = (Button)findViewById(R.id.btnAdd);
         addSnoEditText = (EditText)findViewById(R.id.addSnoEditText);
         addSnameEditText = (EditText)findViewById(R.id.addSnameEditText);
         addClassEditText = (EditText)findViewById(R.id.addClassEditText);
         chk = (CheckBox)findViewById(R.id.appendBox);
         tvShow = (TextView)findViewById(R.id.tvShow);

         btnRead.setOnClickListener(this);
         btnAdd.setOnClickListener(this);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
        case R.id.btnAdd:
        {
            FileOutputStream fos =null;

            //针对文本框是否被选中选择不同的写入方式
            try{

            if(chk.isChecked())
            {
                fos = openFileOutput(fileName, MODE_APPEND);


                String sno = addSnoEditText.getText().toString();
                String sname = addSnameEditText.getText().toString();
                String classes = addClassEditText.getText().toString();

                //将数据写到文本文件中
                String msg  = sno+sname+classes;
                fos.write(msg.getBytes());
                tvShow.setText("文件追加 成功，写入长度："+msg.length());

                 addSnoEditText.setText("");
                 addSnameEditText.setText("");
                 addClassEditText.setText("");
                 Toast.makeText(this, "文件追加", Toast.LENGTH_LONG).show();    
            }else {
                fos = openFileOutput(fileName, MODE_PRIVATE);
                //获取文本框中的输入数据
                String sno = addSnoEditText.getText().toString();
                String sname = addSnameEditText.getText().toString();
                String classes = addClassEditText.getText().toString();

                //将数据写到文本文件中
                String msg  = sno+sname+classes;
                fos.write(msg.getBytes());
                tvShow.setText("文件写入成功，写入长度："+msg.length());

                 addSnoEditText.setText("");
                 addSnameEditText.setText("");
                 addClassEditText.setText("");
                 Toast.makeText(this, "文件写入成功", Toast.LENGTH_LONG).show();  
            }
            }catch (Exception e) {
                // TODO: handle exception
                e.printStackTrace();
                Toast.makeText(this, "写入出错", Toast.LENGTH_LONG);
            }finally {
                if(fos!=null)
                {
                    try{
                        fos.flush();
                        fos.close();
                        fos=null;
                    }catch(Exception e)
                    {

                    }
                }   
            }
            break;
        }   
        case R.id.btnRead:
            {
                tvShow.setText("");
                FileInputStream fis = null;
                try {
                fis  = openFileInput(fileName);

                if (fis.available()==0) {

                    Toast.makeText(this, "文本数据为空不能读入", Toast.LENGTH_LONG);

                    return ;
                }
                else {

                    byte [] bytes = new byte[fis.available()];
                    fis.read(bytes);

                    String msg = new String(bytes,"utf-8");

                    tvShow.setText(msg);
                    Toast.makeText(this, "文本数据读取成功", Toast.LENGTH_LONG);

                }


            }catch (Exception e) {
                // TODO: handle exception


            } finally {
                // TODO: handle finally clause
                if (fis != null){
                    try {

                        fis.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }           
                }
            }   
            break;

            }
        default:
            break;
        }

    }
}

界面显示效果如下

其中xml文件如下

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="com.example.sharepreferencesave.MainActivity" >

     <TableLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content" >
            <TableRow
                android:id="@+id/tableRow1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >
                <TextView
                    android:id="@+id/viewSno"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="学号" />

                  <EditText
                    android:id="@+id/addSnoEditText"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:ems="10" />

            </TableRow>
            <TableRow
                android:id="@+id/tableRow2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >
                <TextView
                    android:id="@+id/viewSname"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="姓名" />
                <EditText
                    android:id="@+id/addSnameEditText"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:ems="10" />
            </TableRow>

            <TableRow
                android:id="@+id/tableRow3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/viewClass"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="班级" />
                <EditText
                    android:id="@+id/addClassEditText"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:ems="10" />
            </TableRow>
            <LinearLayout 
                android:layout_height="wrap_content"
                android:layout_width="wrap_content" >
              <TableLayout 
                  android:layout_width="fill_parent"
                  android:layout_height="wrap_content"
                  >
                  <TableRow
                      android:id="@+id/tableRow4"
                      android:layout_width="wrap_content"
                      android:layout_height="wrap_content" >

                      <Button
                          android:id="@+id/btnAdd"
                          android:layout_width="wrap_content"
                          android:layout_height="wrap_content"
                          android:text="写入" />
                      <TextView
                          android:id="@+id/appendView"
                          android:layout_width="wrap_content"
                          android:layout_height="wrap_content"
                          android:text="追加模式" />

                      <CheckBox
                          android:id="@+id/appendBox"
                          android:layout_width="wrap_content"
                          android:layout_height="wrap_content"
                          android:text="追加" />


                        <Button
                          android:id="@+id/btnRead"
                          android:layout_width="wrap_content"
                          android:layout_height="wrap_content"
                          android:text="读取" />
                  </TableRow>

             </TableLayout>

            </LinearLayout>

     </TableLayout>

     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:orientation="vertical" >

         <TextView
             android:id="@+id/tvShow"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:text="" />

     </LinearLayout>

</LinearLayout>

上面要实现的操作是文件存储，对于一把情况下我们还要实现数据库的存储，所以同样存储上面的信息我们采用数据库存储信息

接下来显示主要的数据库代码
DBAdapter.java

package com.example.usesqlite;

import android.R.integer;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class DBAdapter {

    private final Context context;
    private SQLiteDatabase db;

    private DBHelper dbHelper;

   private final static String DB_TABLE="studentinfo";
   private final static String DB_NAME="student.db";
   private final static int DB_VERSION=1;

   private final static String KEY_ID="id";
   private final static String KEY_SNO="sno";
   private final static String KEY_SNAME="sname";
   private final static String KEY_CLASSES="classes";



    public DBAdapter(Context _cContext) {
        // TODO Auto-generated constructor stub

        context = _cContext;
      }

    //关闭数据库的连接
    public void close()
    {
        if(db!=null)
        {
            db.close();
            db=null;
        }
    }

   public void open() throws SQLiteException
   {
       dbHelper = new DBHelper(context, DB_NAME, null, DB_VERSION);


        try{ 
              db = dbHelper.getWritableDatabase();
            }catch(Exception e)
            {
               db  = dbHelper.getReadableDatabase();
            }
   }

   //插入数据
   public long insert(Student s)
   {

        ContentValues cv = new ContentValues();
        cv.put(KEY_SNO,s.getSno() );
        cv.put(KEY_SNAME, s.getSname());
        cv.put(KEY_CLASSES, s.getClasses());

        return db.insert(DB_TABLE, null, cv);
   }



   //查询所有的数据
   public Student[] findAllStudent()
   {

         Cursor c = db.query(DB_TABLE, null, null, null, null,null, null);
//       while (c.moveToNext()) {
//          System.out.println(c.getString(c.getColumnIndex("sno")));
//          
//      }
         return  convertToStudent(c);
   }



  public long deleteAllStudent()
  {

      return db.delete(DB_TABLE, null, null);

  }


  //这种方发比较好能够防止sql注入
  public long deleteBySno(String sno)
  {
      return db.delete(DB_TABLE, "sno=?", new String[]{sno});
  }

  //这种方式其实不太好存在sql注入的问题，但是一般的情况下是可以使用的
 public long deleteBYId(int id)
 {

     return db.delete(DB_TABLE, "id="+id, null);
 }


 public Student[] findStudentsBySno(String sno)
 {
     Cursor c = db.query(DB_TABLE, null, "sno=?", new String[]{sno}, null, null, null);
     return  convertToStudent(c);
 }

 public long updateOneStudentById(int id,Student s)
 {
     ContentValues cv = new ContentValues();
     cv.put(KEY_SNO, s.getSno());
     cv.put(KEY_SNAME, s.getSname());
     cv.put(KEY_CLASSES, s.getClasses());

     return db.update(DB_TABLE, cv, "id="+id, null);


 }
 public Student[] findOneStudentByID(int ID)
 {

     Cursor c = db.query(DB_TABLE, null, "id="+ID, null, null, null, null);


     return convertToStudent(c);

 }

   //转换函数
   public Student[] convertToStudent(Cursor c)
   {
       int resultsCount = c.getCount();

       if(resultsCount==0||!c.moveToFirst())
       {

           return null;
       }

       Student []stu = new Student[resultsCount];   
       for (int i = 0; i < stu.length; i++) {
//         System.out.println("HHHHH");
//         stu[i].setId(c.getInt(c.getColumnIndex(KEY_ID)));
//         stu[i].setSno(c.getString(c.getColumnIndex(KEY_SNO)));
//         stu[i].setSname(c.getString(c.getColumnIndex(KEY_SNAME)));
//         stu[i].setClasses(c.getString(c.getColumnIndex(KEY_CLASSES)));
//         stu[i].setId(c.getInt(0));
//         System.out.println(sno+"\n"+sname+"\n"+classes+"\n");
//         stu[i].sno=c.getString(c.getColumnIndex(KEY_SNO));
//         stu[i].sname = c.getString(c.getColumnIndex(KEY_SNAME));
//         stu[i].classes = c.getString(c.getColumnIndex(KEY_CLASSES));
//         stu[i].setSno(sno);
//         stu[i].setSname(sname);
//         stu[i].setClasses(classes);
           stu[i] = new Student();
           String sno  = c.getString(c.getColumnIndex("sno"));
           String sname = c.getString(c.getColumnIndex("sname"));
           String classes = c.getString(c.getColumnIndex("classes"));
           stu[i].id=c.getInt(0);
           stu[i].setSno(sno);
           stu[i].setSname(sname);
           stu[i].setClasses(classes);
           //切记不可少了这一句，这个是循环的条件
           c.moveToNext(); 
        }

       return stu;

   }


   //内部的静态类用于创建数据库和建立数据库链接
    private   static class DBHelper extends SQLiteOpenHelper{

        public DBHelper(Context context, String name, CursorFactory factory, int version) {
            super(context, name, factory, version);
            // TODO Auto-generated constructor stub
        }
        private static final String SQL="CREATE TABLE studentinfo ("
                + "id INTEGER PRIMARY KEY AUTOINCREMENT,"
                + "sno TEXT DEFAULT NONE,"
                + "sname TEXT DEFAULT NONE,"
                + "classes TEXT DEFAULT NONE"
                + ")";



        @Override
        public void onCreate(SQLiteDatabase db) {
            // TODO Auto-generated method stub

            db.execSQL(SQL);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            // TODO Auto-generated method stub
            db.execSQL("DROP TABLE IF EXISTS"+DB_TABLE);
            onCreate(db);

        }



    }
}

实体student类

package com.example.usesqlite;

import java.io.Serializable;

public class Student implements Serializable{

    public  int id=-1;
    public String sno;
    public  String sname;
    public String classes;

    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getSno() {
        return sno;
    }
    public void setSno(String sno) {
        this.sno = sno;
    }
    public String getSname() {
        return sname;
    }
    public void setSname(String sname) {
        this.sname = sname;
    }
    public String getClasses() {
        return classes;
    }
    public void setClasses(String classes) {
        this.classes = classes;
    }
    @Override
    public String toString() {
        return "id：" + id +"  " + "学号：" + sno +"  "+ "姓名：" + sname +"  "+ "班级：" + classes ;
    }
}

Mainactivity

package com.example.usesqlite;

import android.R.integer;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Adapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public  class MainActivity extends Activity implements OnClickListener{

    private DBAdapter dbAdapter;
    private EditText addSnoEditText,addSnameEditText,addClassEditText,dleteBySnoEditText,deleteByIdEditText,findBySnoEditText,findOneStudentByIdEditText,updateByIdEditText;
    private Button btnAdd,btnFindAll,btnClearAllData,btnClearShowView,btnDeleteBySno,btnDeleteById,btnFindBySno,btnFindOneStudentById,btnUpdateById;
    private TextView labelShow;

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

//      DB db = new DB(this);
//      SQLiteDatabase dbWrite  =  db.getWritableDatabase();
//      //构造一条数据
//      ContentValues cv = new ContentValues();
//      cv.put("name", "小张");
//      cv.put("sex", "男");
//      dbWrite.insert("user", null, cv);
//      cv = new ContentValues();
//      cv.put("name", "小李");
//      cv.put("sex", "女");
//      dbWrite.insert("user", null, cv);
//      dbWrite.close();
//      SQLiteDatabase dbRead = db.getReadableDatabase();
        //将所有的数据都返回，所以columns这一咧指定为空，代表查询到所有的数据
        //selection代表查询的条件
        //selectionArgs代表查询条件的参数
//       groupBy用于指定分组
//       having用于指定条件
//       orderBy用于指定排序
//      dbRead.query("user", null, "name=?", new String[]{"小张"}, groupBy, having, orderBy)
        //返回值为游标类型的     
//     Cursor cursor = dbRead.query("user", null, null, null, null, null, null);
//     while (cursor.moveToNext()) {
//       String name = cursor.getString(cursor.getColumnIndex("name"));
//       String sex = cursor.getString(cursor.getColumnIndex("sex"));
//       System.out.println(name +"\n" + sex+"\n");
//       }


        btnAdd = (Button)findViewById(R.id.btnAdd);
        btnFindAll = (Button)findViewById(R.id.btnFindAll);
        addSnoEditText = (EditText)findViewById(R.id.addSno);
        addSnameEditText = (EditText)findViewById(R.id.addSname);
        addClassEditText = (EditText)findViewById(R.id.addClass);
        labelShow  = (TextView)findViewById(R.id.labelShow);
        btnClearShowView = (Button)findViewById(R.id.btnClearShowView);
        btnClearAllData = (Button)findViewById(R.id.btnClearAllData);
        btnDeleteById = (Button)findViewById(R.id.btnDeleteById);
        btnDeleteBySno = (Button)findViewById(R.id.btnDeleteBySno);
        dleteBySnoEditText = (EditText)findViewById(R.id.dleteBySnoEditText);
        deleteByIdEditText= (EditText)findViewById(R.id.deleteByIdEditText);
        findBySnoEditText = (EditText)findViewById(R.id.findBySnoEditText);
        updateByIdEditText = (EditText)findViewById(R.id.updateByIdEditText);
        btnUpdateById = (Button)findViewById(R.id.btnUpdateById);
        findOneStudentByIdEditText = (EditText)findViewById(R.id.findOneStudentByIdEditText);
        btnFindBySno = (Button)findViewById(R.id.btnFindBySno);
        btnFindOneStudentById = (Button)findViewById(R.id.btnFindOneStudentById);


        btnAdd.setOnClickListener(this);
        btnFindAll.setOnClickListener(this);
        btnClearShowView.setOnClickListener(this);
        btnClearAllData.setOnClickListener(this);
        btnDeleteById.setOnClickListener(this);
        btnDeleteBySno.setOnClickListener(this);
        btnFindBySno.setOnClickListener(this);
          btnFindOneStudentById .setOnClickListener(this);
          btnUpdateById.setOnClickListener(this);


        dbAdapter = new DBAdapter(this);
        dbAdapter.open();



    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
        //添加数据
        case R.id.btnAdd:
        {
            Student ss = new Student();
            String sno = addSnoEditText.getText().toString();
            String sname = addSnameEditText.getText().toString();
            String classes = addClassEditText.getText().toString();
            ss.setSno(sno);
            ss.setSname(sname);
            ss.setClasses(classes);
            dbAdapter.insert(ss);
            Toast.makeText(this, "添加成功",Toast.LENGTH_LONG).show();

            //清空上一次的文本框输入的数据
            addSnoEditText.setText("");
            addSnameEditText.setText("");
            addClassEditText.setText("");


            //跟新添加数据后的显示频
            Student[] s =dbAdapter.findAllStudent();
            //输出测试
            //          for (int i = 0; i < s.length; i++) {
            //              System.out.println(s[i].getSname()+"\n"+s[i].getClasses()+"\n"+s[i].getSno()+"\n");
            //          }
            if(s==null)
            {
                labelShow.setText("数据库中不存在数据");
                Toast.makeText(this, "数据库中不存在数据", Toast.LENGTH_LONG).show();
                return ;
            }
            else  
            {
                String msg="";
                for (int i = 0; i < s.length; i++)
                {
                    msg += s[i].toString()+"\n";
                }
                labelShow.setText(msg);
            }
            break;  

        }
        //查询到数据库中所有的数据
        case R.id.btnFindAll:
        {
            Student[] s =dbAdapter.findAllStudent();
            //输出测试
            //          for (int i = 0; i < s.length; i++) {
            //              System.out.println(s[i].getSname()+"\n"+s[i].getClasses()+"\n"+s[i].getSno()+"\n");
            //          }
            if(s==null)
            {
                labelShow.setText("数据库中不存在数据");
                Toast.makeText(this, "数据库中不存在数据", Toast.LENGTH_LONG).show();
                return ;
            }
            else  
            {
                String msg="";
                for (int i = 0; i < s.length; i++)
                {
                    msg += s[i].toString()+"\n";
                }
                labelShow.setText(msg);
            }
            break;
        }
        //删除数据库中的所有数据操作
        case R.id.btnClearAllData:
        {
            dbAdapter.deleteAllStudent();
            Toast.makeText(this, "数据库中不存在数据", Toast.LENGTH_LONG).show();
            labelShow.setText("数据全部删除");
            break;
        }
        //清除显示屏幕上的所有数据
        case R.id.btnClearShowView:
        {
            labelShow.setText("");
            Toast.makeText(this, "显示屏清除数据成功", Toast.LENGTH_LONG).show();
            break;
        }
        //按照id来及行删除
        case R.id.btnDeleteById:
        {

            String _id = deleteByIdEditText.getText().toString();

           if ("".equals(_id)) {

                Toast.makeText(this, "ID不能为空", Toast.LENGTH_LONG).show();
                return ;

            }
            int id = Integer.parseInt(_id);
            labelShow.setText("");
            dbAdapter.deleteBYId(id);


            Student[] s =dbAdapter.findAllStudent();
            if(s==null)
            {
                labelShow.setText("数据库中不存在数据");
                Toast.makeText(this, "数据库中不存在数据", Toast.LENGTH_LONG).show();
                return ;
            }
            else  
            {
                String msg="";
                for (int i = 0; i < s.length; i++)
                {
                    msg += s[i].toString()+"\n";
                }
                labelShow.setText(msg);
            }
            Toast.makeText(this, "删除成功", Toast.LENGTH_LONG).show();
            break;
        }
        //按照学号老进行删除
        case R.id.btnDeleteBySno:
        {

              String sno = dleteBySnoEditText.getText().toString();
              if ("".equals(sno)) {

                    Toast.makeText(this, "学号不能为空", Toast.LENGTH_LONG).show();
                    return ;

                }
              dbAdapter.deleteBySno(sno);
             labelShow.setText("");

               Student[] s =dbAdapter.findAllStudent();
                if(s==null)
                {
                    labelShow.setText("数据库中不存在数据");
                    Toast.makeText(this, "数据库中不存在数据", Toast.LENGTH_LONG).show();
                    return ;
                }
                else  
                {
                    String msg="";
                    for (int i = 0; i < s.length; i++)
                    {
                        msg += s[i].toString()+"\n";
                    }
                    labelShow.setText(msg);
                }
            Toast.makeText(this, "删除成功", Toast.LENGTH_LONG).show();
            break;
        }

        case R.id.btnFindBySno:
        {
            String sno = findBySnoEditText.getText().toString();

            if ("".equals(sno)) {

                Toast.makeText(this, "学号不能为空", Toast.LENGTH_LONG).show();
                return ;

            }
            findBySnoEditText.setText("");

             Student []s =dbAdapter.findStudentsBySno(sno);
             labelShow.setText("");

             if(s==null)
                {
                    labelShow.setText("数据库中不存在数据");
                    Toast.makeText(this, "数据库中不存在数据", Toast.LENGTH_LONG).show();
                    return ;
                }
                else  
                {
                    String msg="";
                    for (int i = 0; i < s.length; i++)
                    {
                        msg += s[i].toString()+"\n";
                    }
                    labelShow.setText(msg);
                }

            break;  
        }

        case R.id.btnFindOneStudentById:
        {

            String _id =findOneStudentByIdEditText.getText().toString();
               if ("".equals(_id)) {

                    Toast.makeText(this, "ID不能为空", Toast.LENGTH_LONG).show();
                    return ;

                }
            int id  = Integer.parseInt(_id);
            labelShow.setText("");

            Student[] s = dbAdapter.findOneStudentByID(id);


             if(s==null)
                {
                    labelShow.setText("数据库中不存在数据");
                    Toast.makeText(this, "数据库中不存在数据", Toast.LENGTH_LONG).show();
                    return ;
                }
                else  
                {
                    String msg="";
                    for (int i = 0; i < s.length; i++)
                    {
                        msg += s[i].toString()+"\n";
                    }
                    labelShow.setText(msg);
                }

            break;

        }

        case R.id.btnUpdateById:
        {

            String _id = updateByIdEditText.getText().toString();
               if ("".equals(_id)) {

                    Toast.makeText(this, "ID不能为空", Toast.LENGTH_LONG).show();
                    return ;    
              }
            int id = Integer.parseInt(_id);
            String sno = addSnoEditText.getText().toString();
            String sname = addSnameEditText.getText().toString();
            String classes = addClassEditText.getText().toString();

            Student ss = new Student();
            ss.setId(id);
            ss.setSno(sno);
            ss.setSname(sname);
            ss.setClasses(classes);
            dbAdapter.updateOneStudentById(id, ss);

            //查询跟新的数据 显示出来

            Student[] s =dbAdapter.findAllStudent();
            //输出测试
            //          for (int i = 0; i < s.length; i++) {
            //              System.out.println(s[i].getSname()+"\n"+s[i].getClasses()+"\n"+s[i].getSno()+"\n");
            //          }
            if(s==null)
            {
                labelShow.setText("数据库中不存在数据");
                Toast.makeText(this, "数据库中不存在数据", Toast.LENGTH_LONG).show();
                return ;
            }
            else  
            {
                String msg="";
                for (int i = 0; i < s.length; i++)
                {
                    msg += s[i].toString()+"\n";
                }
                labelShow.setText(msg);
            }
            break;  
        }

        default:

            break;
        }
    }
}

xml文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.usesqlite.MainActivity"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >

        <TableLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content" >

            <TableRow
                android:id="@+id/tableRow1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/viewSno"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="学号" />

                <EditText
                    android:id="@+id/addSno"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:ems="10" >

                    <requestFocus />
                </EditText>

            </TableRow>

            <TableRow
                android:id="@+id/tableRow2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/viewSname"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="姓名" />

                <EditText
                    android:id="@+id/addSname"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:ems="10" />

            </TableRow>

            <TableRow
                android:id="@+id/tableRow3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/viewClass"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="班级" />

                <EditText
                    android:id="@+id/addClass"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:ems="10" />

            </TableRow>

            <LinearLayout android:layout_height="wrap_content" >

            <TableRow
                android:id="@+id/tableRow4"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <Button
                    android:id="@+id/btnAdd"
                    android:layout_width="120px"
                    android:layout_height="wrap_content"
                    android:text="添加" />

                <Button
                    android:id="@+id/btnUpdateById"
                    android:layout_width="180px"
                    android:layout_height="wrap_content"
                    android:text="更新根据ID" />
                <EditText
                    android:id="@+id/updateByIdEditText"
                    android:layout_width="120px"
                    android:layout_height="wrap_content"
                    android:ems="10" />


            </TableRow>
           </LinearLayout>
        </TableLayout>







    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >

        <TableLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content" >

            <TableRow
                android:id="@+id/tableRow5"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <Button
                    android:id="@+id/btnFindAll"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="查询所有" />

                <Button
                    android:id="@+id/btnFindBySno"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="学号查询" />

                <EditText
                    android:id="@+id/findBySnoEditText"
                    android:layout_width="135px"
                    android:layout_height="wrap_content"
                    android:ems="10" />

            </TableRow>

              <TableRow
                android:id="@+id/tableRow6"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <Button
                    android:id="@+id/btnClearShowView"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="清除显示" />

                <Button
                    android:id="@+id/btnDeleteBySno"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="学号删除" />

                <EditText
                    android:id="@+id/dleteBySnoEditText"
                    android:layout_width="135px"
                    android:layout_height="wrap_content"
                    android:ems="10" />

            </TableRow>




                <TableRow
                android:id="@+id/tableRow7"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" >

                <Button
                    android:id="@+id/btnClearAllData"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="删除所有" />

                <Button
                    android:id="@+id/btnDeleteById"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="ID删除" />

                <EditText
                    android:id="@+id/deleteByIdEditText"
                    android:layout_width="135px"
                    android:layout_height="wrap_content"
                    android:ems="10" />

            </TableRow>



        </TableLayout>

    </LinearLayout>

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

         <Button
             android:id="@+id/btnFindOneStudentById"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignParentLeft="true"
             android:layout_alignParentTop="true"
             android:text="ID查询" />

         <EditText
             android:id="@+id/findOneStudentByIdEditText"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignBaseline="@+id/findOneStudentById"
             android:layout_alignBottom="@+id/findOneStudentById"
             android:layout_alignParentRight="true"
             android:ems="10" />

    </RelativeLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/labelShow"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="" />

    </LinearLayout>

</LinearLayout>

最终的实现效果

代码链接
http://pan.baidu.com/s/1miAsLoW
http://pan.baidu.com/s/1bNUdYY