android中SQLite数据库操作例程

1、环境：

Windows7，eclipse4.41+adt

2、主要文件：

androidManifest.xml文件：工程说明文件

activity_main.xml文件：activity布局文件

listvie.xml文件：activity中ListView的布局文件

dbHelper.java文件：SQLiteOpenHelper的子类

MainActivity.java文件：Activity的子类

3、运行结果：

4、核心代码：

（1）androidManifest.xml

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.mydbdemo"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="18" />    <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name="com.example.mydbdemo.MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application></manifest>

（2）activity_main.xml

<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=".MainActivity" >    <LinearLayout        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_centerHorizontal="true"        android:orientation="vertical" >        <LinearLayout            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:addStatesFromChildren="true">                        <TextView                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:text="name"                android:textColor="?android:attr/textColorSecondary"/>            <EditText                android:id="@+id/et_name"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_weight="1"                android:singleLine="true"/>        </LinearLayout>        <LinearLayout            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:addStatesFromChildren="true">                        <TextView                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:text="age  "                android:textColor="?android:attr/textColorSecondary"/>            <EditText                android:id="@+id/et_age"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_weight="0.5"                android:singleLine="true" />        </LinearLayout>        <LinearLayout            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:addStatesFromChildren="true"            android:gravity="center">            <Button                 android:id="@+id/bt_add"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:text="add"/>            <Button                 android:id="@+id/bt_modify"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:text="modify"/>            <Button                 android:id="@+id/bt_delete"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:text="delete"/>            <Button                 android:id="@+id/bt_select"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:text="select"/>                    </LinearLayout>        <ListView             android:id="@+id/listView"            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:padding="20dip">                    </ListView>    </LinearLayout></RelativeLayout>

（3）listvie.xml

<?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">    <TextView         android:id="@+id/tvID"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_weight="0.4"/>    <TextView         android:id="@+id/tvName"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_weight="0.3"/>    <TextView         android:id="@+id/tvAge"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_weight="0.3"/></LinearLayout>

（4）dbHelper.java

package com.example.mydbdemo;import android.content.Context;import android.database.sqlite.*;import android.database.sqlite.SQLiteDatabase.CursorFactory;/** * 本类主要实现数据库和表的创建，以及数据更新。 * @author 秦子文 * 20140304 */public class dbHelper extends SQLiteOpenHelper{public static final String TB_NAME="friends";public dbHelper(Context context,  //上下文环境String name,   //数据库名称CursorFactory factory,   //索引工厂函数int version) {      //版本号super(context, name, factory, version);// TODO Auto-generated constructor stub }//创建表，数据库第一次生成是会自动调用这个方法，一般在此方法中生成数据库的表。@Overridepublic void onCreate(SQLiteDatabase db) {// TODO Auto-generated method stub//注意TB_NAME前后要加空格   sql语句大小写不敏感db.execSQL("create table if not exists "+TB_NAME+" (_id integer primary key autoincrement,name varchar,age integer)");}//数据库更新时，系统主动调用这个方法@Overridepublic void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {// TODO Auto-generated method stubdb.execSQL("DROP TABLE IF EXISTS"+TB_NAME);onCreate(db);}}

（5）MainActivity.java

package com.example.mydbdemo;import java.util.ArrayList;import java.util.HashMap;import java.util.Map;import android.os.Bundle;import android.app.Activity;import android.content.ContentValues;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.util.Log;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.ListView;import android.widget.SimpleAdapter;/** * 本类是Activity的子类主要用于与用户的交互 * add按钮可以将EditText框中的文字添加到数据库 * modify按钮可以将ListView中选中的条目修改 * delete按钮可以将ListView中选中的条目删除 * 默认选中select按钮 * @author 秦子文 * 20150304 */public class MainActivity extends Activity {private static String DB_NAME="mydb";private EditText et_name;private EditText et_age;private ArrayList<Map<String,Object>> data;private dbHelper dbHelper;private SQLiteDatabase db;private Cursor cursor;private SimpleAdapter listAdapter;private View view;private ListView listview;private Button selBtn,addBtn,updBtn,delBtn;private Map<String,Object> item;private String selId;private ContentValues selCV;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//获取各个控件的引用et_name = (EditText)findViewById(R.id.et_name);et_age  = (EditText)findViewById(R.id.et_age);listview = (ListView)findViewById(R.id.listView);selBtn = (Button)findViewById(R.id.bt_select);addBtn = (Button)findViewById(R.id.bt_add);updBtn = (Button)findViewById(R.id.bt_modify);delBtn = (Button)findViewById(R.id.bt_delete);//为Button设置监听器，监听器接口均由对应的内部类实现selBtn.setOnClickListener(new selbutton());addBtn.setOnClickListener(new addbutton());updBtn.setOnClickListener(new modifybutton());delBtn.setOnClickListener(new delbutton());//创建数据库dbHelper = new dbHelper(this,DB_NAME,null,1);//得到数据库引用。也可调用dbHelper.getReadableDatabase()方法，视情况而定db = dbHelper.getWritableDatabase();//创建ArrayList<Map<String,Object>>data = new ArrayList<Map<String,Object>>();dbFindAll();  //检索数据库中的所有数据并显示//为ListView添加监听器listview.setOnItemClickListener(new OnItemClickListener(){@Overridepublic void onItemClick(AdapterView<?> parent, View v, int position,long id) {// TODO Auto-generated method stub//将手指点击位置条目的所有数据保存到Map中Map<String,Object> listItem = (Map<String,Object>)listview.getItemAtPosition(position);//将对应数据显示到EditText控件中et_name.setText((String)listItem.get("name"));et_age.setText((String)listItem.get("age"));//保存选中idselId = (String)listItem.get("_id");}});}//Button监听接口实现类public class addbutton implements OnClickListener{@Overridepublic void onClick(View arg0) {// TODO Auto-generated method stubdbAdd();   //添加数据dbFindAll();}}public class delbutton implements OnClickListener{@Overridepublic void onClick(View arg0) {// TODO Auto-generated method stubdbDel();  //删除数据dbFindAll();}}public class modifybutton implements OnClickListener{@Overridepublic void onClick(View arg0) {// TODO Auto-generated method stubdbUpdate();  //修改数据dbFindAll();}}public class selbutton implements OnClickListener{@Overridepublic void onClick(View arg0) {// TODO Auto-generated method stubdbFindAll();}}protected void dbFindAll(){data.clear();cursor = db.query(dbHelper.TB_NAME,  //表名null,    //columnsnull,    //selectionnull, //selectionArgsnull, //groupBynull,    //having"_id ASC");    //orderBycursor.moveToFirst();while(!cursor.isAfterLast()){String id = cursor.getString(0);String name = cursor.getString(1);String age = cursor.getString(2);item = new HashMap<String,Object>();item.put("_id", id);item.put("name", name);item.put("age", age);data.add(item);cursor.moveToNext();}showList();}protected void dbAdd(){ContentValues values = new ContentValues(); //键值对类似于mapvalues.put("name", et_name.getText().toString().trim());  //得到EditText中的数据并整形，存入对应键下values.put("age", et_age.getText().toString().trim());long rowid = db.insert(dbHelper.TB_NAME, //表名null,   //空列的默认值values);  //列名和对应的列值if(-1 == rowid){Log.i("myDBDemo","数据插入失败！");}else{Log.i("myDBDemo","数据插入成功！");}}protected void dbUpdate(){ContentValues values = new ContentValues();values.put("name", et_name.getText().toString().trim());values.put("age", et_age.getText().toString().trim());String where = "_id="+selId;int i = db.update(dbHelper.TB_NAME,  //表名  values,    //更新的列和对应数据  where,     //更新条件  null);   //更新条件数据if(i>0){Log.i("mydbDemo","数据更新成功！");}else{Log.i("mydbDemo","数据更新失败！");}}protected void dbDel(){String where = "_id="+selId;int i = db.delete(dbHelper.TB_NAME,  //表名where,  //删除条件null);  //删除条件数组if(i>0){Log.i("myDbDemo","数据删除成功！");}else{Log.i("myDbDemo","数据删除失败！");}}//ListView显示数据private void showList(){listAdapter = new SimpleAdapter(this,    //山下文环境data,    //要显示的数据，类型为ArrayList<Map<String,Object>>R.layout.listview,   //listView引用的布局文件，即res/layout/listview.xmlnew String[]{"_id","name","age"},    //data中的键名数组new int[]{R.id.tvID,R.id.tvName,R.id.tvAge});  //要显示上面键名的控件数组，该id来自于res/layout/listview.xmllistview.setAdapter(listAdapter);   //将此适配器设置为res/layout/activity_main.xml中ListView的适配器}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}}

5、工程完整代码：

http://download.csdn.net/detail/a_cainiao_a/8473383

6、恳请批评指正。