SQLite

package mars.sqlite3;

import mars.sqlite3.db.DatabaseHelper;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class SQLiteActivity extends Activity {
    /** Called when the activity is first created. */
	private Button createButton;
	private Button insertButton;
	private Button updateButton;
	private Button updateRecordButton;
	private Button queryButton;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        createButton = (Button)findViewById(R.id.createDatabase);
        updateButton = (Button)findViewById(R.id.updateDatabase);
        insertButton = (Button)findViewById(R.id.insert);
        updateRecordButton = (Button)findViewById(R.id.update);
        queryButton = (Button)findViewById(R.id.query);
        createButton.setOnClickListener(new CreateListener());
        updateButton.setOnClickListener(new UpdateListener());
        insertButton.setOnClickListener(new InsertListener());
        updateRecordButton.setOnClickListener(new UpdateRecordListener());
        queryButton.setOnClickListener(new QueryListener());
    }
    class CreateListener implements OnClickListener{
		@Override
		public void onClick(View v) {
			//创建一个DatabaseHelper对象
			DatabaseHelper dbHelper = new DatabaseHelper(SQLiteActivity.this,"test_mars_db");
			//只有调用了atabaseHelper对象的getReadableDatabase()方法，或者是getWritableDatabase()方法之后，才会创建数据库
			SQLiteDatabase db = dbHelper.getReadableDatabase();
		}
    }
    class UpdateListener implements OnClickListener{

		@Override
		public void onClick(View v) {
			DatabaseHelper dbHelper = new DatabaseHelper(SQLiteActivity.this,"test_mars_db",2);
			SQLiteDatabase db = dbHelper.getReadableDatabase();
		}
    	
    }
    class InsertListener implements OnClickListener{

		@Override
		public void onClick(View v) {
			//生成ContentValues对象
			ContentValues values = new ContentValues();
			//向该对象中插入键值对，其中键是列名，值是希望插入这一列的值，值必须跟列的数据类型匹配
			values.put("id",1);
			values.put("name","zhangsan");
			DatabaseHelper dbHelper = new DatabaseHelper(SQLiteActivity.this,2);
			SQLiteDatabase db = dbHelper.getWritableDatabase();
			//调用insert方法，就可以将数据插入到数据库当中
			db.insert("user",null,values);
		}
    }
    //更新操作就相当于执行SQL语句中的update语句
    //UPDATE table_name SET XXCOL=XXX WHERE XXCOL=XX...
    class UpdateRecordListener implements OnClickListener{

		@Override
		public void onClick(View arg0) {
			// TODO Auto-generated method stub
	////	/得到一个可写的SQLiteDatabase对象
			DatabaseHelper dbHelper = new DatabaseHelper(SQLiteActivity.this,"test_mars_db");
			SQLiteDatabase db = dbHelper.getWritableDatabase();
			ContentValues values = new ContentValues();
			values.put("name","zhangsanfeng");
			//第一个参数是要更新的表名
			//第二个参数是一个ContentValeus对象
			//第三个参数是where字句
			db.update("user",values,"id=?",new String[]{"1"});
		}
    }
    class QueryListener implements OnClickListener{

		@Override
		public void onClick(View v) {
			System.out.println("aaa------------------");
			Log.d("myDebug","myFirstDebugMsg");
			
			DatabaseHelper dbHelper = new DatabaseHelper(SQLiteActivity.this,"test_mars_db");
			SQLiteDatabase db = dbHelper.getReadableDatabase();
			Cursor cursor = db.query("user",new String[]{"id","name"},new String[]{"1"},null);
			while(cursor.moveToNext()){
				String name = cursor.getString(cursor.getColumnIndex("name"));
				System.out.println("query--->" + name);
			}
		}
    }
    
}

package mars.sqlite3.db;

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

//DatabaseHelper作为一个访问SQLite的助手类，提供两个方面的功能
//第一，getReadableDatabase(),getWritableDatabase()可以获得SQLiteDatabse对象，通过该对象可以对数据库进行操作
//第二，提供了onCreate()和onUpgrade()两个回调函数，允许我们在创建和升级数据库的时候，进行自己的操作

public class DatabaseHelper extends SQLiteOpenHelper {
	
	private static final int VERSION = 1;
	//在SQLiteOepnHelper的子类当中，必须有该构造函数
	public DatabaseHelper(Context context,String name,CursorFactory factory,int version) {
		//必须通过super调用父类当中的构造函数
		super(context,name,factory,version);
		// TODO Auto-generated constructor stub
	}
	public DatabaseHelper(Context context,String name){
		this(context,VERSION);
	}
	public DatabaseHelper(Context context,int version){
		this(context,version);
	}

	//该函数是第一次创建数据库的时候执行，实际上是在第一得到SQLiteDatabse对象的时候，才会调用此方法 
	@Override
	public void onCreate(SQLiteDatabase db) {
		// TODO Auto-generated method stub
		System.out.println("create a Database");
		//execSQL函数用于执行SQL语句
		db.execSQL("create table user(id int,name varchar(20))");
	}

	@Override
	public void onUpgrade(SQLiteDatabase db,int oldVersion,int newVersion) {
		// TODO Auto-generated method stub
		System.out.println("update a Database");
	}

}

（编辑：李大同）

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