Android开发学习笔记：数据存取之SQLite浅析

package com.lingdududu.testSQLite;  
 
import com.lingdududu.testSQLiteDb.StuDBHelper;  

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.View.OnClickListener;  
12.import android.widget.Button;  
13./*  
14. * @author lingdududu  
15. */ 
16.public class SQLiteActivity extends Activity {  
17.    /** Called when the activity is first created. */ 
18.    //声明各个按钮  
19.    private Button createBtn;  
20.    private Button insertBtn;  
21.    private Button updateBtn;  
22.    private Button queryBtn;  
23.    private Button deleteBtn;  
24.    private Button ModifyBtn;  
25.    @Override 
26.    public void onCreate(Bundle savedInstanceState) {  
27.        super.onCreate(savedInstanceState);  
28.        setContentView(R.layout.main);  
29.          
30.        //调用creatView方法  
31.        creatView();  
32.        //setListener方法  
33.        setListener();          
34.    }  
35.      
36.    //通过findViewById获得Button对象的方法  
37.    private void creatView(){  
38.        createBtn = (Button)findViewById(R.id.createDatabase);  
39.        updateBtn = (Button)findViewById(R.id.updateDatabase);  
40.        insertBtn = (Button)findViewById(R.id.insert);  
41.        ModifyBtn = (Button)findViewById(R.id.update);  
42.        queryBtn = (Button)findViewById(R.id.query);  
43.        deleteBtn = (Button)findViewById(R.id.delete);  
44.    }  
45.      
46.    //为按钮注册监听的方法  
47.    private void setListener(){  
48.        createBtn.setOnClickListener(new CreateListener());  
49.        updateBtn.setOnClickListener(new UpdateListener());  
50.        insertBtn.setOnClickListener(new InsertListener());  
51.        ModifyBtn.setOnClickListener(new  ModifyListener());  
52.        queryBtn.setOnClickListener(new QueryListener());  
53.        deleteBtn.setOnClickListener(new DeleteListener());  
54.    }  
55.      
56.    //创建数据库的方法  
57.    class CreateListener implements OnClickListener{  
58. 
59.        @Override 
60.        public void onClick(View v) {  
61.            //创建StuDBHelper对象  
62.            StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,1);  
63.            //得到一个可读的SQLiteDatabase对象  
64.            SQLiteDatabase db =dbHelper.getReadableDatabase();  
65.        }         
66.    }  
67.      
68.    //更新数据库的方法  
69.    class UpdateListener implements OnClickListener{  
70. 
71.        @Override 
72.        public void onClick(View v) {  
73.            // 数据库版本的更新,由原来的1变为2  
74.            StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,2);  
75.            SQLiteDatabase db =dbHelper.getReadableDatabase();  
76.        }         
77.    }  
78.      
79.    //插入数据的方法  
80.    class InsertListener implements OnClickListener{  
81. 
82.        @Override 
83.        public void onClick(View v) {  
84. 
85.            StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,1);  
86.            //得到一个可写的数据库  
87.            SQLiteDatabase db =dbHelper.getWritableDatabase();  
88.              
89.            //生成ContentValues对象 //key:列名，value:想插入的值    
90.            ContentValues cv = new ContentValues();  
91.            //往ContentValues对象存放数据，键-值对模式  
92.            cv.put("id", 1);  
93.            cv.put("sname", "xiaoming");  
94.            cv.put("sage", 21);  
95.            cv.put("ssex", "male");  
96.            //调用insert方法，将数据插入数据库  
97.            db.insert("stu_table", null, cv);  
98.            //关闭数据库  
99.            db.close();  
100.        }         
101.    }  
102.      
103.    //查询数据的方法  
104.    class QueryListener implements OnClickListener{  
105. 
106.        @Override 
107.        public void onClick(View v) {  
108. 
109.            StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,1);  
110.            //得到一个可写的数据库  
111.            SQLiteDatabase db =dbHelper.getReadableDatabase();  
112.            //参数1：表名    
113.            //参数2：要想显示的列    
114.            //参数3：where子句    
115.            //参数4：where子句对应的条件值    
116.            //参数5：分组方式    
117.            //参数6：having条件    
118.            //参数7：排序方式    
119.            Cursor cursor = db.query("stu_table", new String[]{"id","sname","sage","ssex"}, "id=?", new String[]{"1"}, null, null, null);  
120.            while(cursor.moveToNext()){  
121.                String name = cursor.getString(cursor.getColumnIndex("sname"));  
122.                String age = cursor.getString(cursor.getColumnIndex("sage"));  
123.                String sex = cursor.getString(cursor.getColumnIndex("ssex"));  
124.                System.out.println("query------->" + "姓名："+name+" "+"年龄："+age+" "+"性别："+sex);  
125.            }  
126.            //关闭数据库  
127.            db.close();  
128.        }         
129.    }  
130.      
131.    //修改数据的方法  
132.    class ModifyListener implements OnClickListener{  
133. 
134.        @Override 
135.        public void onClick(View v) {  
136. 
137.            StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,1);  
138.            //得到一个可写的数据库  
139.            SQLiteDatabase db =dbHelper.getWritableDatabase();  
140.            ContentValues cv = new ContentValues();  
141.            cv.put("sage", "23");  
142.            //where 子句 "?"是占位符号，对应后面的"1",  
143.            String whereClause="id=?";  
144.            String [] whereArgs = {String.valueOf(1)};  
145.            //参数1 是要更新的表名  
146.            //参数2 是一个ContentValeus对象  
147.            //参数3 是where子句  
148.            db.update("stu_table", cv, whereClause, whereArgs);  
149.        }  
150.    }  
151.      
152.    //删除数据的方法  
153.    class DeleteListener implements OnClickListener{  
154. 
155.        @Override 
156.        public void onClick(View v) {  
157. 
158.            StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,1);  
159.            //得到一个可写的数据库  
160.            SQLiteDatabase db =dbHelper.getReadableDatabase();  
161.            String whereClauses = "id=?";  
162.            String [] whereArgs = {String.valueOf(2)};  
163.            //调用delete方法，删除数据   
164.            db.delete("stu_table", whereClauses, whereArgs);  
165.        }     
166.    }  
167.}