Android 数据库SQLite的使用简单Demo

在手机开发中SQLite的使用demo

简单的bean类

Java代码

package com.easyway.android.sql;
/**
* 普通JavaBean
* @author longgangbai
*
*/
public class CityBean {
public static final String ID = "_id";
public static final String CITY = "city";
public static final String CODE = "code";
private String id;
private String city;
private String code;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
}

界面展现类：

Java代码

package com.easyway.android.sql;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
/**
*
*
* 本例实现SQLite数据库增加、删除、修改、模糊查询操作。这里不是最好的实现方法,
* 如想研究SQL如何封装，请详细查看SQLiteDatebase类.
* 查看SQL语句：String sql = SQLiteQueryBuilder.buildQueryString();
*
*
* @author longgangbai
*/
public class AndroidSQL extends Activity {
private static String DB_NAME = "mycity.db";
private static int DB_VERSION = 1;
private static int POSTION;
private ListView listview;
private Cursor cursor;
private SQLiteDatabase db;
private SQLiteHelper dbHelper;
private ListAdapter listAdapter;
private EditText etCity;
private EditText etCode;
private Button bt_add;
private Button bt_modify;
private Button bt_query;
private List<CityBean> cityList = new ArrayList<CityBean>();
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
etCity = (EditText) findViewById(R.id.etCity);
etCode = (EditText) findViewById(R.id.etCode);
bt_add = (Button) findViewById(R.id.bt_add);
bt_modify = (Button) findViewById(R.id.bt_modify);
bt_query = (Button) findViewById(R.id.bt_query);
try{
/* 初始化并创建数据库 */
dbHelper = new SQLiteHelper(this, DB_NAME, null, DB_VERSION);
/* 创建表 */
db = dbHelper.getWritableDatabase(); //调用SQLiteHelper.OnCreate()
/* 查询表，得到cursor对象 */
cursor = db.query(SQLiteHelper.TB_NAME, null, null, null, null, null, CityBean.CODE + " DESC");
cursor.moveToFirst();
while(!cursor.isAfterLast() && (cursor.getString(1) != null)){
CityBean city = new CityBean();
city.setId(cursor.getString(0));
city.setCity(cursor.getString(1));
city.setCode(cursor.getString(2));
cityList.add(city);
cursor.moveToNext();
}
}catch(IllegalArgumentException e){
//当用SimpleCursorAdapter装载数据时，表ID列必须是_id，否则报错column '_id' does not exist
e.printStackTrace();
//当版本变更时会调用SQLiteHelper.onUpgrade()方法重建表注：表以前数据将丢失
++ DB_VERSION;
dbHelper.onUpgrade(db, --DB_VERSION, DB_VERSION);
// dbHelper.updateColumn(db, SQLiteHelper.ID, "_"+SQLiteHelper.ID, "integer");
}
listview = (ListView)findViewById(R.id.listView);
listAdapter = new ListAdapter();
listview.setAdapter(listAdapter);
listview.setOnItemClickListener(new ListView.OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view, int postion,
long arg3) {
setSelectedValues(postion);
}
});
/* 插入表数据并ListView显示更新 */
bt_add.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View arg0) {
if(etCity.getText().length() > 1 && etCode.getText().length() >1){
ContentValues values = new ContentValues();
values.put(CityBean.CITY, etCity.getText().toString().trim());
values.put(CityBean.CODE, etCode.getText().toString().trim());
//插入数据用ContentValues对象也即HashMap操作,并返回ID号
Long cityID = db.insert(SQLiteHelper.TB_NAME, CityBean.ID, values);
CityBean city = new CityBean();
city.setId(""+cityID);
city.setCity(etCity.getText().toString().trim());
city.setCode(etCode.getText().toString().trim());
cityList.add(city);
listview.setAdapter(new ListAdapter());
resetForm();
}
}
});
/* 查询表，模糊条件查询 */
bt_query.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View view) {
cityList.removeAll(cityList);
String sql = null;
String sqlCity = etCity.getText().length() > 0 ? CityBean.CITY + " like '%" + etCity.getText().toString().trim() + "%'" : "";
String sqlCode = etCode.getText().length() > 0 ? CityBean.CITY + " like '%" + etCity.getText().toString().trim() + "%'" : "";
if( (!"".equals(sqlCity)) && (!"".equals(sqlCode)) ){
sql = sqlCity + " and" + sqlCode;
}else if(!"".equals(sqlCity)){
sql = sqlCity;
}else if(!"".equals(sqlCode)){
sql = sqlCode;
}
cursor = db.query(true, SQLiteHelper.TB_NAME,
new String[]{CityBean.ID, CityBean.CITY, CityBean.CODE},
sql,
null, null, null, null, null);
cursor.moveToFirst();
while(!cursor.isAfterLast() && (cursor.getString(1) != null)){
CityBean city = new CityBean();
city.setId(cursor.getString(0));
city.setCity(cursor.getString(1));
city.setCode(cursor.getString(2));
cityList.add(city);
cursor.moveToNext();
}
listview.setAdapter(new ListAdapter());
resetForm();
}
});
/* 修改表数据 */
bt_modify.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View arg0) {
ContentValues values = new ContentValues();
values.put(CityBean.CITY, etCity.getText().toString().trim());
values.put(CityBean.CODE, etCode.getText().toString().trim());
db.update(SQLiteHelper.TB_NAME, values, CityBean.ID + "=" + cityList.get(POSTION).getId(), null);
cityList.get(POSTION).setCity(etCity.getText().toString().trim());
cityList.get(POSTION).setCode(etCode.getText().toString().trim());
listview.setAdapter(new ListAdapter());
resetForm();
}
});
}
/* 设置选中ListView的值 */
public void setSelectedValues(int postion){
POSTION = postion;
etCity.setText(cityList.get(postion).getCity());
etCode.setText(cityList.get(postion).getCode());
}
/* 重值form */
public void resetForm(){
etCity.setText("");
etCode.setText("");
}
@Override
protected void onDestroy() {
db.delete(SQLiteHelper.TB_NAME, null, null);
super.onDestroy();
}
private class ListAdapter extends BaseAdapter{
public ListAdapter(){
super();
}
@Override
public int getCount() {
return cityList.size();
}
@Override
public Object getItem(int postion) {
return postion;
}
@Override
public long getItemId(int postion) {
return postion;
}
@Override
public View getView(final int postion, View view, ViewGroup parent) {
view = getLayoutInflater().inflate(R.layout.listview, null);
TextView tv = (TextView) view.findViewById(R.id.tvCity);
tv.setText("" + cityList.get(postion).getCity());
TextView bu = (TextView) view.findViewById(R.id.btRemove);
bu.setText(R.string.delete);
bu.setId(Integer.parseInt(cityList.get(postion).getId()));
/* 删除表数据 */
bu.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View view) {
try{
db.delete(SQLiteHelper.TB_NAME, CityBean.ID + "=" + view.getId(), null);
cityList.remove(postion);
listview.setAdapter(new ListAdapter());
}catch(Exception e){
e.printStackTrace();
}
}
});
return view;
}
}
}

SQLite实现类：

Java代码

package com.easyway.android.sql;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
/**
* 实现对表的创建、更新、变更列名操作
*
* 在Android 中针对少量数据的操作在SQLite操作实现相关功能功能
* ，但是必须继承SQLiteOpenHelper，实现相关的功能。
*
*
* @author longgangbai
*
*/
public class SQLiteHelper extends SQLiteOpenHelper {
public static final String TB_NAME = "citys";
public SQLiteHelper(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
}
/**
* 创建新表
*/
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE IF NOT EXISTS " +
TB_NAME + "(" +
CityBean.ID + " integer primary key," +
CityBean.CITY + " varchar," +
CityBean.CODE + " integer"+
")");
}
/**
* 当检测与前一次创建数据库版本不一样时，先删除表再创建新表
*/
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TB_NAME);
onCreate(db);
}
/**
* 变更列名
* @param db
* @param oldColumn
* @param newColumn
* @param typeColumn
*/
public void updateColumn(SQLiteDatabase db, String oldColumn, String newColumn, String typeColumn){
try{
db.execSQL("ALTER TABLE " +
TB_NAME + " CHANGE " +
oldColumn + " "+ newColumn +
" " + typeColumn
);
}catch(Exception e){
e.printStackTrace();
}
}
}

AndroidSQL.rar (90.7 KB)