前言：上個月與同學一起做了一個簡單的Android應用，這段時間正好沒有很多事情所以趁熱整理一下學習到的知識，剛開始學習Android還有很多不懂的地方，繼續努力吧！

作業中需要用到資料庫，當然首選Android集成了的SQLite資料庫。

直接使用資料庫可以這樣：

//開啟或建立test.db資料庫
SQLiteDatabase db = openOrCreateDatabase("test.db", Context.MODE_PRIVATE, null);  

//建立person表
db.execSQL("CREATE TABLE IF NOT EXISTS person([id] INTEGER PRIMARY KEY, [name] TEXT)");

//查詢
Cursor cursor = db.rawQuery("select * from person where name = " + "'urbain'", null);
if(cursor.moveToNext()) {
    id = Integer.parseInt( cursor.getString(0) );
    name = cursor.getString(1);
}

//更新刪除操作均可用db.execSQL(string)來操作
 

利用listView顯示資料庫中的資料要加一個adapter，步驟：
1.將Sqlite資料庫的內容查詢出來並放入陣列列表中，形成ListView的資料來源；
2.adapter介面卡繫結資料來源，顯示在ListView item中。

自己寫類DatabaseHelper繼承SQLiteOpenHelper並實現部分資料庫操作：

package com.zkurbain.wenriji;

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

public class DatabaseHelper extends SQLiteOpenHelper{

    private static final int VERSION = 1;  
    public DatabaseHelper(Context context, String name, CursorFactory factory,
            int version) {
        super(context, name, factory, version);
    }

    public DatabaseHelper(Context context, String name){  
            this(context, name, VERSION);  
    }

    public DatabaseHelper(Context context, String name, int version){
        this(context, name, null, version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        //建立表
        String crtWenTable = "CREATE TABLE IF NOT EXISTS [wenti]([wentiHash] INTENGER PRIMARY KEY, [wentiName] TEXT)" ;
        db.execSQL(crtWenTable);

        //如果資料庫為空，則預置一些資料
        Cursor cursor = db.rawQuery("select * from wenti", null);
        if( !cursor.moveToNext()){
            String[] swen = {"我今天讀書了嗎？",    "我明天打算做什麼？",   "今天吃啥好吃的？"};

            db.beginTransaction(); //開始事務處理 
            for (String s : swen) {
                db.execSQL("insert into wenti values(" + s.hashCode() + ", '"+ s +"')");
            }
            db.setTransactionSuccessful();  //設定事務標誌為成功，當結束事務時就會提交事務 
            db.endTransaction(); //結束事務
        }
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}
 

在主類中，藉助SimpleAdapter使資料顯示在listView：

package com.zkurbain.wenriji;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class ChooseWen extends Activity {

    private ListView listView = null;
    private List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
    private SimpleAdapter simpleAdapter = null;

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

        listView = (ListView) findViewById(android.R.id.list);

        simpleAdapter = new SimpleAdapter(this, getdata(), R.layout.list,
                new String[] { "wentiName" }, new int[] { R.id.wenti });

        //listView繫結adapter
        listView.setAdapter(simpleAdapter);
    }

    private List<Map<String, Object>> getdata() {
        DatabaseHelper dbHelper = new DatabaseHelper(ChooseWen.this,
                "wenriji.db");
        SQLiteDatabase db = dbHelper.getReadableDatabase();
        Cursor cursor = db.rawQuery("select * from wenti", null);

        // 清空list
        list.clear();
        // 查詢到的資料新增到list集合
        while (cursor.moveToNext()) {
            String wenti = cursor.getString(1);
            Map<String, Object> map = new HashMap<String, Object>();
            map.put("wentiName", wenti); // 獲取name
            list.add(map);
        }

        return list;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.choose_wen, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        return super.onOptionsItemSelected(item);
    }
}
 

下面是XML檔案內容:

<RelativeLayout 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.wenriji.wenriji.ChooseWen"
    android:id="@+id/activity_choose_wen" >

    <ListView
        android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true" >
        <requestFocus />
    </ListView>

</RelativeLayout>