增删改查

package com.example.acud;

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

import android.os.Bundle;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

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

    public void add(View v) {
        StuOpenHelper helper = new StuOpenHelper(this);
        SQLiteDatabase db = helper.getWritableDatabase();
        String name = ((EditText) findViewById(R.id.et_name)).getText()
                .toString();
        int age = Integer.parseInt(((EditText) findViewById(R.id.et_age))
                .getText().toString());

        // 原生sql操作,
        // db.execSQL("insert into stuinfo (name,age) values('lisi',22)");
        // db.execSQL("insert into stuinfo (name,age) values(?,?)",new
        // Object[]{"kitty",30});
        db.execSQL("insert into stuinfo (name,age) values(?,?)", new Object[] {
                name,age });
        Toast.makeText(this, "ok", 0).show();
        //google API操作  见教材P124,更推荐用这种

    }

    public void delete(View view) {
        StuOpenHelper helper = new StuOpenHelper(this);
        SQLiteDatabase db = helper.getWritableDatabase();
        db.execSQL("delete from stuinfo where _id=?", new Object[] { 2 });
        Toast.makeText(this, "删除成功", 0).show();

    }

    public void update(View view) {
        StuOpenHelper helper = new StuOpenHelper(this);
        SQLiteDatabase db = helper.getWritableDatabase();
        db.execSQL("update stuinfo set name=? where _id=?", new Object[] {
                "micky", 3 });
        Toast.makeText(this, "修改成功", 0).show();

    }
    
    //定义学生集合
    List<Student> list=new ArrayList<Student>();

    public void search(View view) {
        System.out.println(list.size()+"在search里");
        StuOpenHelper helper = new StuOpenHelper(this);
        SQLiteDatabase db = helper.getWritableDatabase();
    //    String s = "";
        Cursor cursor = db.rawQuery("select * from stuinfo", null);
        if (cursor.getCount() != 0) {
            //每循环一次，创建一个学生对象并添加到集合中
            while (cursor.moveToNext()) {
//                s += cursor.getInt(0) + "   " + cursor.getString(1) + "   "
//                        + cursor.getInt(2) + "
";
                Student s1=new Student();
                s1.setId(cursor.getInt(0));
                s1.setName(cursor.getString(1));
                s1.setAge(cursor.getInt(2));
                list.add(s1);
                
            }
        }
        ListView lv=(ListView) findViewById(R.id.lv1);
        lv.setAdapter(new myadapter());

        // Toast.makeText(this, s, 0).show();
    //    ((TextView) (findViewById(R.id.tv_show))).setText(s);

    }
    private class myadapter extends BaseAdapter{

        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return list.size();
        }
        @Override
        public View getView(int position, View convertView, ViewGroup arg2) {
    
            // TODO Auto-generated method stub
            View view=View.inflate(MainActivity.this, R.layout.list_item, null);
            TextView tvid=(TextView)view.findViewById(R.id.tv_id);
            TextView tvname=(TextView)view.findViewById(R.id.tv_name);
            TextView tvage=(TextView) view.findViewById(R.id.tv_age);
    
            System.out.println(list.get(position).getId());            
            tvid.setText(list.get(position).getId()+"");
            tvname.setText(list.get(position).getName());
            tvage.setText(list.get(position).getAge()+"");        
            
//            tvid.setText("aa");
//            tvname.setText("bb");
//            tvage.setText("cc");    
            
            
            return view;
        }



        @Override
        public Object getItem(int arg0) {
            // TODO Auto-generated method stub
            return null;
        }



        @Override
        public long getItemId(int arg0) {
            // TODO Auto-generated method stub
            return 0;
        }
        
    }

}

package com.example.acud;

public class Student {
    private int id;
    private String name;
    private int age;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }

}

package com.example.acud;

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

public class StuOpenHelper extends SQLiteOpenHelper {

    public StuOpenHelper(Context context) {
        super(context, "stu.db", null, 1);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        db.execSQL("create table stuinfo(_id integer primary key autoincrement,name varchar(20),age integer)");

    }

    @Override
    public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
        // TODO Auto-generated method stub

    }

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
 
    android:orientation="vertical"
    android:padding="16dp" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="130dp" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="姓  名 ："
            android:textSize="18sp" />

        <EditText
            android:id="@+id/et_name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入姓名"
            android:textSize="16sp" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="年  龄："
            android:textSize="18sp" />

        <EditText
            android:id="@+id/et_age"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="输入年龄"
            android:textSize="16sp" />
    </LinearLayout>

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

        <Button
            android:id="@+id/btn_add"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginRight="2dp"
            android:layout_weight="1"
            android:background="#B9B9FF"
            android:onClick="add"
            android:text="添加"
            android:textSize="18sp" />

        <Button
            android:id="@+id/btn_query"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginRight="2dp"
            android:layout_weight="1"
            android:background="#DCB5FF"
            android:onClick="search"
            android:text="查询"
            android:textSize="18sp" />

        <Button
            android:id="@+id/btn_update"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginRight="2dp"
            android:layout_weight="1"
            android:background="#E6CAFF"
            android:onClick="update"
            android:text="修改"
            android:textSize="18sp" />

        <Button
            android:id="@+id/btn_delete"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="#ACD6FF"
            android:onClick="delete"
            android:text="删除"
            android:textSize="18sp" />
    </LinearLayout>

   

        <ListView
            android:id="@+id/lv1"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:layout_marginTop="25dp"
            android:textSize="20sp" />
   
</LinearLayout>

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

    <TextView
        android:id="@+id/tv_id"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="1" />

    <TextView
        android:id="@+id/tv_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="2" />

    <TextView
        android:id="@+id/tv_age"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="3" />

</LinearLayout>