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  

1. package com.easyway.android.sql;  
2. /** 
3.  * 普通JavaBean 
4.  * @author longgangbai 
5.  * 
6.  */  
7. public class CityBean {  
8.     public static final String ID = "_id";  
9.     public static final String CITY = "city";  
10.     public static final String CODE = "code";  
11.       
12.     private String id;  
13.     private String city;  
14.     private String code;  
15.       
16.     public String getId() {  
17.         return id;  
18.     }  
19.     public void setId(String id) {  
20.         this.id = id;  
21.     }  
22.     public String getCity() {  
23.         return city;  
24.     }  
25.     public void setCity(String city) {  
26.         this.city = city;  
27.     }  
28.     public String getCode() {  
29.         return code;  
30.     }  
31.     public void setCode(String code) {  
32.         this.code = code;  
33.     }  
34.   
35. }  

界面展现类：

Java代码  

1. package com.easyway.android.sql;  
2.   
3. import java.util.ArrayList;  
4. import java.util.List;  
5.   
6. import android.app.Activity;  
7. import android.content.ContentValues;  
8. import android.database.Cursor;  
9. import android.database.sqlite.SQLiteDatabase;  
10. import android.os.Bundle;  
11. import android.view.View;  
12. import android.view.ViewGroup;  
13. import android.widget.AdapterView;  
14. import android.widget.BaseAdapter;  
15. import android.widget.Button;  
16. import android.widget.EditText;  
17. import android.widget.ListView;  
18. import android.widget.TextView;  
19.   
20. /** 
21.  *  
22.  *  
23.  * 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, 
24.  * 如想研究SQL如何封装，请详细查看SQLiteDatebase类. 
25.  * 查看SQL语句：String sql = SQLiteQueryBuilder.buildQueryString(); 
26.  *  
27.  *  
28.  * @author  longgangbai 
29.  */  
30. public class AndroidSQL extends Activity {  
31.     private static String DB_NAME = "mycity.db";  
32.     private static int DB_VERSION = 1;  
33.     private static int POSTION;  
34.     private ListView listview;  
35.     private Cursor cursor;  
36.     private SQLiteDatabase db;  
37.     private SQLiteHelper dbHelper;  
38.     private ListAdapter listAdapter;  
39.       
40.     private EditText etCity;  
41.     private EditText etCode;  
42.     private Button bt_add;  
43.     private Button bt_modify;  
44.     private Button bt_query;  
45.       
46.     private List<CityBean> cityList = new ArrayList<CityBean>();  
47.     /** Called when the activity is first created. */  
48.     @Override  
49.     public void onCreate(Bundle savedInstanceState) {  
50.         super.onCreate(savedInstanceState);  
51.         setContentView(R.layout.main);  
52.           
53.         etCity = (EditText) findViewById(R.id.etCity);  
54.         etCode = (EditText) findViewById(R.id.etCode);  
55.         bt_add = (Button) findViewById(R.id.bt_add);  
56.         bt_modify = (Button) findViewById(R.id.bt_modify);  
57.         bt_query = (Button) findViewById(R.id.bt_query);  
58.           
59.         try{  
60.             /* 初始化并创建数据库 */  
61.             dbHelper = new SQLiteHelper(this, DB_NAME, null, DB_VERSION);  
62.             /* 创建表 */  
63.             db = dbHelper.getWritableDatabase();    //调用SQLiteHelper.OnCreate()           
64.             /* 查询表，得到cursor对象 */  
65.             cursor = db.query(SQLiteHelper.TB_NAME, null, null, null, null, null, CityBean.CODE + " DESC");  
66.             cursor.moveToFirst();  
67.             while(!cursor.isAfterLast() && (cursor.getString(1) != null)){      
68.                 CityBean city = new CityBean();  
69.                 city.setId(cursor.getString(0));  
70.                 city.setCity(cursor.getString(1));  
71.                 city.setCode(cursor.getString(2));  
72.                 cityList.add(city);  
73.                 cursor.moveToNext();  
74.             }  
75.         }catch(IllegalArgumentException e){  
76.             //当用SimpleCursorAdapter装载数据时，表ID列必须是_id，否则报错column '_id' does not exist  
77.             e.printStackTrace();  
78.             //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  
79.             ++ DB_VERSION;  
80.             dbHelper.onUpgrade(db, --DB_VERSION, DB_VERSION);  
81. //          dbHelper.updateColumn(db, SQLiteHelper.ID, "_"+SQLiteHelper.ID, "integer");  
82.         }  
83.         listview = (ListView)findViewById(R.id.listView);  
84.         listAdapter = new ListAdapter();  
85.         listview.setAdapter(listAdapter);  
86.         listview.setOnItemClickListener(new ListView.OnItemClickListener(){  
87.             @Override  
88.             public void onItemClick(AdapterView<?> parent, View view, int postion,  
89.                     long arg3) {  
90.                 setSelectedValues(postion);  
91.             }             
92.         });  
93.           
94.         /* 插入表数据并ListView显示更新 */  
95.         bt_add.setOnClickListener(new Button.OnClickListener(){  
96.             @Override  
97.             public void onClick(View arg0) {  
98.                 if(etCity.getText().length() > 1 && etCode.getText().length() >1){  
99.                     ContentValues values = new ContentValues();  
100.                     values.put(CityBean.CITY, etCity.getText().toString().trim());  
101.                     values.put(CityBean.CODE, etCode.getText().toString().trim());  
102.                     //插入数据 用ContentValues对象也即HashMap操作,并返回ID号  
103.                     Long cityID = db.insert(SQLiteHelper.TB_NAME, CityBean.ID, values);  
104.                     CityBean city = new CityBean();  
105.                     city.setId(""+cityID);  
106.                     city.setCity(etCity.getText().toString().trim());  
107.                     city.setCode(etCode.getText().toString().trim());  
108.                     cityList.add(city);  
109.                     listview.setAdapter(new ListAdapter());  
110.                     resetForm();  
111.                 }  
112.             }  
113.         });  
114.           
115.         /* 查询表，模糊条件查询 */  
116.         bt_query.setOnClickListener(new Button.OnClickListener(){  
117.             @Override  
118.             public void onClick(View view) {  
119.                 cityList.removeAll(cityList);  
120.                 String sql = null;  
121.                 String sqlCity = etCity.getText().length() > 0 ? CityBean.CITY + " like '%" + etCity.getText().toString().trim() + "%'" : "";                  
122.                 String sqlCode = etCode.getText().length() > 0 ? CityBean.CITY + " like '%" + etCity.getText().toString().trim() + "%'" : "";  
123.                 if( (!"".equals(sqlCity)) && (!"".equals(sqlCode)) ){  
124.                     sql = sqlCity + " and" + sqlCode;  
125.                 }else if(!"".equals(sqlCity)){  
126.                     sql = sqlCity;  
127.                 }else if(!"".equals(sqlCode)){  
128.                     sql = sqlCode;  
129.                 }  
130.                 cursor = db.query(true, SQLiteHelper.TB_NAME,   
131.                         new String[]{CityBean.ID, CityBean.CITY, CityBean.CODE},   
132.                         sql,   
133.                         null, null, null, null, null);  
134.                 cursor.moveToFirst();  
135.                 while(!cursor.isAfterLast() && (cursor.getString(1) != null)){    
136.                     CityBean city = new CityBean();  
137.                     city.setId(cursor.getString(0));  
138.                     city.setCity(cursor.getString(1));  
139.                     city.setCode(cursor.getString(2));  
140.                     cityList.add(city);  
141.                     cursor.moveToNext();  
142.                 }  
143.                 listview.setAdapter(new ListAdapter());  
144.                 resetForm();  
145.             }  
146.         });  
147.           
148.         /* 修改表数据 */  
149.         bt_modify.setOnClickListener(new Button.OnClickListener(){  
150.             @Override  
151.             public void onClick(View arg0) {  
152.                 ContentValues values = new ContentValues();  
153.                 values.put(CityBean.CITY, etCity.getText().toString().trim());  
154.                 values.put(CityBean.CODE, etCode.getText().toString().trim());  
155.                 db.update(SQLiteHelper.TB_NAME, values, CityBean.ID + "=" + cityList.get(POSTION).getId(), null);  
156.                 cityList.get(POSTION).setCity(etCity.getText().toString().trim());  
157.                 cityList.get(POSTION).setCode(etCode.getText().toString().trim());  
158.                 listview.setAdapter(new ListAdapter());  
159.                 resetForm();  
160.             }  
161.         });  
162.     }  
163.       
164.     /* 设置选中ListView的值 */  
165.     public void setSelectedValues(int postion){  
166.         POSTION = postion;  
167.         etCity.setText(cityList.get(postion).getCity());  
168.         etCode.setText(cityList.get(postion).getCode());  
169.     }  
170.       
171.     /* 重值form */  
172.     public void resetForm(){  
173.         etCity.setText("");  
174.         etCode.setText("");  
175.     }  
176.       
177.     @Override  
178.     protected void onDestroy() {  
179.         db.delete(SQLiteHelper.TB_NAME, null, null);  
180.         super.onDestroy();  
181.     }  
182.       
183.     private class ListAdapter extends BaseAdapter{  
184.         public ListAdapter(){  
185.             super();  
186.         }  
187.         @Override  
188.         public int getCount() {  
189.             return cityList.size();  
190.         }  
191.   
192.         @Override  
193.         public Object getItem(int postion) {  
194.             return postion;  
195.         }  
196.   
197.         @Override  
198.         public long getItemId(int postion) {  
199.             return postion;  
200.         }  
201.   
202.         @Override  
203.         public View getView(final int postion, View view, ViewGroup parent) {  
204.             view = getLayoutInflater().inflate(R.layout.listview, null);  
205.             TextView tv = (TextView) view.findViewById(R.id.tvCity);  
206.             tv.setText("" + cityList.get(postion).getCity());  
207.             TextView bu = (TextView) view.findViewById(R.id.btRemove);  
208.             bu.setText(R.string.delete);  
209.             bu.setId(Integer.parseInt(cityList.get(postion).getId()));  
210.               
211.             /* 删除表数据 */  
212.             bu.setOnClickListener(new Button.OnClickListener(){  
213.                 @Override  
214.                 public void onClick(View view) {  
215.                     try{  
216.                         db.delete(SQLiteHelper.TB_NAME, CityBean.ID + "=" + view.getId(), null);  
217.                         cityList.remove(postion);  
218.                         listview.setAdapter(new ListAdapter());                       
219.                     }catch(Exception e){  
220.                         e.printStackTrace();  
221.                     }  
222.                 }  
223.             });  
224.             return view;  
225.         }  
226.     }  
227. }  

SQLite实现类：

Java代码  

1. package com.easyway.android.sql;  
2.   
3. import android.content.Context;  
4. import android.database.sqlite.SQLiteDatabase;  
5. import android.database.sqlite.SQLiteOpenHelper;  
6. import android.database.sqlite.SQLiteDatabase.CursorFactory;  
7. /** 
8.  * 实现对表的创建、更新、变更列名操作 
9.  *  
10.  * 在Android 中针对少量数据的操作在SQLite操作实现相关功能功能 
11.  * ，但是必须继承SQLiteOpenHelper，实现相关的功能。 
12.  *   
13.  *  
14.  * @author longgangbai 
15.  * 
16.  */  
17. public class SQLiteHelper extends SQLiteOpenHelper {  
18.     public static final String TB_NAME = "citys";  
19.   
20.     public SQLiteHelper(Context context, String name, CursorFactory factory,  
21.             int version) {  
22.         super(context, name, factory, version);  
23.     }  
24.       
25.     /** 
26.      * 创建新表 
27.      */  
28.     @Override  
29.     public void onCreate(SQLiteDatabase db) {  
30.         db.execSQL("CREATE TABLE IF NOT EXISTS " +  
31.                 TB_NAME + "(" +  
32.                 CityBean.ID + " integer primary key," +  
33.                 CityBean.CITY + " varchar," +   
34.                 CityBean.CODE + " integer"+  
35.                 ")");  
36.     }  
37.       
38.     /** 
39.      * 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 
40.      */  
41.     @Override  
42.     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {  
43.         db.execSQL("DROP TABLE IF EXISTS " + TB_NAME);  
44.         onCreate(db);  
45.     }  
46.       
47.     /** 
48.      * 变更列名 
49.      * @param db 
50.      * @param oldColumn 
51.      * @param newColumn 
52.      * @param typeColumn 
53.      */  
54.     public void updateColumn(SQLiteDatabase db, String oldColumn, String newColumn, String typeColumn){  
55.         try{  
56.             db.execSQL("ALTER TABLE " +  
57.                     TB_NAME + " CHANGE " +  
58.                     oldColumn + " "+ newColumn +  
59.                     " " + typeColumn  
60.             );  
61.         }catch(Exception e){  
62.             e.printStackTrace();  
63.         }  
64.     }  
65.   
66. }  

• AndroidSQL.rar (90.7 KB)