SQLite 数据库操作

package com.example.njupt.zhb.sqlite1;
import java.util.ArrayList;
import java.util.List;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.view.View;
import android.view.View.OnClickListener;
public class MainActivity extends Activity implements OnClickListener{
    public static final String DB_NAME="studentdata.db";
    Button insertBtn;
    Button updataGBtn;
    Button updataABtn;
    Button deleteBtn;
    Button selectBtn;
    Button displayBtn;
    Button closeBtn;
    ListView mListView;
    SQLiteDatabase db;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mListView=new ListView(this);
        BtnInit();
        OpenCreateDB();
    }
    public void OpenCreateDB(){
    	db = openOrCreateDatabase(DB_NAME, this.MODE_PRIVATE, null);
        db.execSQL("DROP TABLE IF EXISTS students");  
        db.execSQL("CREATE TABLE IF NOT EXISTS students (_id INTEGER PRIMARY KEY AUTOINCREMENT, name VARCHAR, age INTEGER,grade INTEGER, info VARCHAR)");
    }
    //插入数据到students表
    public void InsertData(){
    	Student liSi =new Student("李四", 22, 87, "南京邮电大学 通信工程");
        Student liHua = new Student("李华", 23, 78, "南京邮电大学 软件工程");
        db.execSQL("INSERT INTO students VALUES (NULL,?,?,?,?)", new Object[]{"张三",21,98,"南京邮电大学 电子信息工程"});
        db.execSQL("INSERT INTO students VALUES (NULL,?,?,?,?)", new Object[]{liSi.name,liSi.age,liSi.grade,liSi.info});
        db.execSQL("INSERT INTO students VALUES (NULL,'王五',19,99,'南京邮电大学 网络工程')");
        ContentValues cvOfLiHua = new ContentValues();
        cvOfLiHua.put("name", liHua.name);
        cvOfLiHua.put("age", liHua.age);
        cvOfLiHua.put("grade", liHua.grade);
        cvOfLiHua.put("info", liHua.info);
        db.insert("students", null, cvOfLiHua);
        Log.d("msg","插入结束");
        Toast.makeText(this, "插入数据完成！", Toast.LENGTH_SHORT).show();
    }
    public void UpdateGrade(){
    	ContentValues cv = new ContentValues();  
    	cv.put("grade", 85);  
    	//更新数据,将李四的成绩改为85分
    	db.update("students", cv, "name = ?", new String[]{"李四"});  
    	Log.d("msg","李四的成绩已更新");
    	Toast.makeText(this, "李四的成绩已更新", Toast.LENGTH_SHORT).show();
    }
    public void UpdateAge(){
    	String sqlString="UPDATE students SET age=18 WHERE grade= 78";
    	db.execSQL(sqlString);
    	Log.d("msg","李华的年龄已更新");
    	Toast.makeText(this, "李华的年龄已更新", Toast.LENGTH_SHORT).show();
    }
    public void Delete(){
    	db.execSQL("DELETE FROM students WHERE name='张三'");
    	Log.d("msg","张三的信息已经被删除");
    	Toast.makeText(this, "张三的信息已经被删除", Toast.LENGTH_SHORT).show();
    }
    public void Select(){
    	List<String> list=new ArrayList<String>();
    	Cursor c = db.rawQuery("SELECT * FROM students WHERE grade >= ?", new String[]{"86"});
    	Log.d("msg","--------------大于86分的同学----------------------------");
    	while (c.moveToNext()) {
        	Student person = new Student();
        	person._id = c.getInt(c.getColumnIndex("_id"));
        	person.name = c.getString(c.getColumnIndex("name"));
        	person.grade=c.getInt(c.getColumnIndex("grade"));
        	person.age = c.getInt(c.getColumnIndex("age"));
        	person.info = c.getString(c.getColumnIndex("info"));
        	String string=""+person._id+" "+person.name+" "+person.grade+" "+person.age+" "+person.info;
        	list.add(string);
        	Log.d("msg",string);
        }
        c.close();
        ArrayAdapter<String> adapter=new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1,list);
        mListView.setAdapter(adapter);
    }
    public void Display(){
    	List<String> list=new ArrayList<String>();
    	Cursor c = db.rawQuery("SELECT * FROM students", null);
        while (c.moveToNext()) {
        	Student person = new Student();
        	person._id = c.getInt(c.getColumnIndex("_id"));
        	person.name = c.getString(c.getColumnIndex("name"));
        	person.grade=c.getInt(c.getColumnIndex("grade"));
        	person.age = c.getInt(c.getColumnIndex("age"));
        	person.info = c.getString(c.getColumnIndex("info"));
        	String string=""+person._id+" "+person.name+" "+person.grade+" "+person.age+" "+person.info;
        	list.add(string);
        	Log.d("msg",string);
        }
        c.close();
        ArrayAdapter<String> adapter=new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1,list);
        mListView.setAdapter(adapter);
    }
    public void Close(){
    	db.close();
    }
    public void BtnInit(){
    	insertBtn=(Button)findViewById(R.id.insert);
        updataGBtn=(Button)findViewById(R.id.updataG);
        updataABtn=(Button)findViewById(R.id.updataA);
        deleteBtn=(Button)findViewById(R.id.delete);
        selectBtn=(Button)findViewById(R.id.select);
        displayBtn=(Button)findViewById(R.id.display);
        closeBtn=(Button)findViewById(R.id.close);
        mListView=(ListView)findViewById(R.id.listview);
        insertBtn.setOnClickListener(this);
        updataABtn.setOnClickListener(this);
        updataGBtn.setOnClickListener(this);
        deleteBtn.setOnClickListener(this);
        selectBtn.setOnClickListener(this);
        displayBtn.setOnClickListener(this);
        closeBtn.setOnClickListener(this);
    }
	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
		switch(v.getId()){
		case R.id.insert:
			InsertData();
			break;
		case R.id.updataA:
			UpdateAge();
			break;
		case R.id.updataG:
			UpdateGrade();
			break;
		case R.id.display:
			Display();
			break;
		case R.id.delete:
			Delete();
			break;
		case R.id.select:
			Select();
			break;
		case R.id.close:
			Close();
			break;
		}
	}
}

http://blog.csdn.net/nupt123456789/article/details/7891887