Android整理：SQlite数据库的使用以及通过listView显示数据

前言：上个月与同学一起做了一个简单的Android应用，这段时间正好没有很多事情所以趁热整理一下学习到的知识，刚开始学习Android还有很多不懂的地方，继续努力吧！

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作业中需要用到数据库，当然首选Android集成了的SQLite数据库。

直接使用数据库可以这样：

//打开或创建test.db数据库SQLiteDatabase db = openOrCreateDatabase("test.db", Context.MODE_PRIVATE, null);  //创建person表db.execSQL("CREATE TABLE IF NOT EXISTS person([id] INTEGER PRIMARY KEY, [name] TEXT)");//查询Cursor cursor = db.rawQuery("select * from person where name = " + "'urbain'", null);if(cursor.moveToNext()) {    id = Integer.parseInt( cursor.getString(0) );    name = cursor.getString(1);}//更新删除操作均可用db.execSQL(string)来操作

利用listView显示数据库中的数据要加一个adapter，步骤：
1.将Sqlite数据库的内容查询出来并放入数组列表中，形成ListView的数据源；
2.adapter适配器绑定数据源，显示在ListView item中。

自己写类DatabaseHelper继承SQLiteOpenHelper并实现部分数据库操作：

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) {        //创建表        String crtWenTable = "CREATE TABLE IF NOT EXISTS [wenti]([wentiHash] INTENGER PRIMARY KEY, [wentiName] TEXT)" ;        db.execSQL(crtWenTable);        //如果数据库为空，则预置一些数据        Cursor cursor = db.rawQuery("select * from wenti", null);        if( !cursor.moveToNext()){            String[] swen = {"我今天读书了吗？",    "我明天打算做什么？",   "今天吃啥好吃的？"};            db.beginTransaction(); //开始事务处理             for (String s : swen) {                db.execSQL("insert into wenti values(" + s.hashCode() + ", '"+ s +"')");            }            db.setTransactionSuccessful();  //设置事务标志为成功，当结束事务时就会提交事务             db.endTransaction(); //结束事务        }    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {    }}

在主类中，借助SimpleAdapter使数据显示在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绑定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();        // 查询到的数据添加到list集合        while (cursor.moveToNext()) {            String wenti = cursor.getString(1);            Map<String, Object> map = new HashMap<String, Object>();            map.put("wentiName", wenti); // 获取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文件内容:

<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>