安卓开发：学生信息管理小程序

成品图

打开程序，实现添加学生，及时显示数据库内容,男女分别用相应的图片表示，点击垃圾桶可以删除这一行的学生，刷新数据，停留在刚才的位置：

1.activity_main.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:android1="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="学生信息管理系统" />

    <EditText 
        android1:id="@+id/name"
       android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android1:hint="请输入学生姓名" />

   <RadioGroup
       android1:orientation="horizontal"
        android1:id="@+id/sex"
        android1:layout_width="match_parent"
        android1:layout_height="wrap_content" 
          >

        <RadioButton
            android1:id="@+id/male"
            android1:layout_width="0dp"
            android1:layout_weight="1"
            android1:layout_height="wrap_content"
            android1:checked="true"
            android1:text="男" />

        <RadioButton
            android1:id="@+id/female"
            android1:layout_weight="1"
            android1:layout_width="0dp"
            android1:layout_height="wrap_content"
            android1:text="女" />

    </RadioGroup>

   <Button 
        android1:id="@+id/saveInfo"
        android:onClick="saveInfo"
       android:layout_width="match_parent"
       android:layout_height="wrap_content" 
       android1:text="保存" 
       />

<!--    能够处理上万条滚动数据的滑动
  原理是能够及时回收没有在屏幕显示的对象 -->
       <ListView 
           android1:id="@+id/lv"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
           ></ListView>
</LinearLayout>

2. item.xml(显示数据库学生的信息)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
   >

    <ImageView 
        android:id="@+id/iv_sex"
        android:layout_width="25dp"
        android:layout_height="25dp"
         <!--     需要在drawable-hdpi 中添加男人标志图片 -->
        android:src="@drawable/man"
        />
    <TextView 
        android:id="@+id/tv_name"
        android:layout_toRightOf="@id/iv_sex"
        android:gravity="center_vertical"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="姓名"
        android:textSize="22sp"
        android:textColor="#ff0000"
        android:layout_marginLeft="20dp"
        />

    <ImageView 
        android:id="@+id/iv_delete"
        android:layout_alignParentRight="true"
        android:layout_marginRight="50dp"
        android:layout_width="25dp"
        android:layout_height="25dp" 
        <!--     需要在drawable-hdpi 中添加垃圾桶图片 -->
        android:src="@drawable/delete"
        />
</RelativeLayout>

3. MainActivity.java

package com.zt.studentsystemv2;

import java.util.List;

import com.zt.studentdbhelper.Student;
import com.zt.studentdbhelper.StudentDao;

import android.app.Activity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RadioButton;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private EditText name;
    private RadioButton male,female;
    private ListView lv;
    private Button save;
//  private LinearLayout viewInfo;
    private String stuName,sex;
    StudentDao dao = new StudentDao(this, "student.db", null, 1);
    boolean isStart=true;
    private List<Student> stuInfo;
    private MyAdapter myAdapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
  //      viewInfo = (LinearLayout) findViewById(R.id.info);
        lv=(ListView) findViewById(R.id.lv);
        refreshData();
    }

    private void init() {   
        name = (EditText) findViewById(R.id.name);
        male = (RadioButton) findViewById(R.id.male);
        female = (RadioButton) findViewById(R.id.female);
        save = (Button) findViewById(R.id.saveInfo);

        stuName = name.getText().toString().trim();


        if (TextUtils.isEmpty(stuName)){
            alter("姓名不能为空");
            isStart=false;
            return ;
        }
        sex = male.isChecked()?"男":"女";
        isStart=true;
    }

    private void alter(String info) {
        Toast.makeText(this, info, 5).show();
    }
    public void saveInfo(View v) {
        init();
        if (!isStart) return;
        dao.add(stuName, sex);
        alter("保存成功!");
        refreshData();
    }

    private void refreshData() {
        stuInfo = dao.find();
        if (myAdapter==null){
            myAdapter = new MyAdapter();
            lv.setAdapter(myAdapter);
        }else{
            //通知数据适配器更新数据,而不是new出来新的数据适配器
            myAdapter.notifyDataSetChanged();
        }

    }

    class MyAdapter extends BaseAdapter{

        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {
            View item = null;
            if (convertView==null){
                //把一个布局xml文件转化成view对象
                item = View.inflate(MainActivity.this,R.layout.item, null);
            }else{
                //利用回收的对象
                item = convertView;
            }
            ImageView sex=(ImageView) item.findViewById(R.id.iv_sex);
            Student stu = stuInfo.get(position);
            if ("男".equals(stu.getSex())){
                sex.setImageResource(R.drawable.man);
            }else{
                sex.setImageResource(R.drawable.woman);
            }
            TextView tv = (TextView) item.findViewById(R.id.tv_name);
            tv.setText(stu.getName());

            ImageView delete = (ImageView) item.findViewById(R.id.iv_delete);
            delete.setOnClickListener(new OnClickListener() {                   
                @Override
                public void onClick(View v) {
                    Student stu = stuInfo.get(position);
                    //从数据库删除数据
                    dao.delete(stu.getName(), stu.getSex());
                    alter("删除成功!");
                    //更新ui
                    refreshData();
                }
            });
            return item;
        }
        @Override
        public int getCount() {

            return stuInfo.size();
        }

        @Override
        public long getItemId(int position) {
            // TODO Auto-generated method stub
            return 0;
        }

        @Override
        public Object getItem(int position) {
            // TODO Auto-generated method stub
            return null;
        }


    }
}

4.sqlLite数据库的操作:

Student.java:

package com.zt.studentdbhelper;

public class Student {

    private String name;
    private String sex;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }

}

StudentDBHelper.java:

package com.zt.studentdbhelper;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class StudentDBHelper extends SQLiteOpenHelper {

    public StudentDBHelper(Context context, String name, CursorFactory factory,
            int version) {
        super(context, name, factory, version);

    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        db.execSQL("create table student(_id integer primary key autoincrement,name varchar(20),sex varchar(4) check(sex in ('男','女')))");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.i("MainActivity","建表完成！");

    }

}

StudentDao:

package com.zt.studentdbhelper;

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;


public class StudentDao {

    private StudentDBHelper helper;

    public StudentDao(Context context, String name, CursorFactory factory,
            int version) {
        helper=new StudentDBHelper(context, name, factory, version);
    }
    /**
     * 添加一个学生
     * @param name
     * @param phone
     */
    public void add(String name,String sex) {
        SQLiteDatabase  sqlHelper = helper.getWritableDatabase();
        sqlHelper.execSQL("insert into student(name,sex)values(?,?)", new Object[]{name,sex});
        sqlHelper.close();
    }

    public void delete(String name,String sex) {
        SQLiteDatabase  sqlHelper = helper.getWritableDatabase();
        sqlHelper.execSQL("delete from student where name =? and sex=?", new Object[]{name,sex});
        sqlHelper.close();
    }

    public List<Student>  find() {
        List<Student> list = new ArrayList<Student>();
        SQLiteDatabase  sqlHelper = helper.getReadableDatabase();
        Cursor  cur = sqlHelper.rawQuery("select name,sex from student where name is not null and  sex is not null", null);
        boolean result = cur.moveToNext();

        while (result){
            Student stu= new Student();
            stu.setName(cur.getString(0));
            stu.setSex(cur.getString(1));
            list.add(stu);
            result= cur.moveToNext();
        }
        cur.close();
        sqlHelper.close();
        return list;
    }

}

查看数据库：

将/sdk/platform-tools加入环境变量；
cmd下使用adb shell ，cd 进入相应包，进入数据库目录
输入sqLite3 student.db，select * from student;