android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
private Button create_database = null ;
private Button update_database = null ;
private Button insert = null ;
private Button update = null ;
private Button query = null ;
private Button delete = null ;
@Override
public void onCreate(Bundle savedInstanceState) {
super .onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
create_database = (Button)findViewById(R.id.create_database);
create_database.setOnClickListener( new CreateDatabaseOnClickListener());
update_database = (Button)findViewById(R.id.update_database);
update_database.setOnClickListener( new UpdateDatabaseOnClickListener());
insert = (Button)findViewById(R.id.insert);
insert.setOnClickListener( new InsertOnClickListener());
update = (Button)findViewById(R.id.update);
update.setOnClickListener( new UpdateOnClickListener());
query = (Button)findViewById(R.id.query);
query.setOnClickListener( new QueryOnClickListener());
delete = (Button)findViewById(R.id.delete);
delete.setOnClickListener( new DeleteOnClickListener());
}
public class CreateDatabaseOnClickListener implements OnClickListener{
public void onClick(View v) {
// TODO Auto-generated method stub
// 创建一个DatabaseHelper类的对象，该类是单独一个java文件,这里采用2个参数的构造函数，建立的数据
// 库的名字为tornadomeet.db
DatabaseHelper database_helper = new DatabaseHelper(MainActivity. this , "tornadomeet.db" );
// 只有调用getReadableDatabase()或者getWriteableDatabase()函数后才能返回一个SQLiteDatabase对象
SQLiteDatabase db = database_helper.getReadableDatabase();
}
}
public class UpdateDatabaseOnClickListener implements OnClickListener{
public void onClick(View v) {
// TODO Auto-generated method stub
DatabaseHelper database_helper = new DatabaseHelper(MainActivity. this , "tornadomeet.db", 2 );
SQLiteDatabase db = database_helper.getReadableDatabase();
}
}
public class InsertOnClickListener implements OnClickListener{
public void onClick(View v) {
// 生成contentvallues对象，该对象用来存数据的
ContentValues values = new ContentValues();
values.put( "id", 1); // 注意值的类型要匹配
values.put("name", "tornado" );
DatabaseHelper database_helper = new DatabaseHelper(MainActivity. this , "tornadomeet.db" );
SQLiteDatabase db = database_helper.getWritableDatabase(); // 这里是获得可写的数据库
db.insert("user1", null , values);
}
}
public class UpdateOnClickListener implements OnClickListener{
public void onClick(View v) {
// TODO Auto-generated method stub
DatabaseHelper database_helper = new DatabaseHelper(MainActivity. this , "tornadomeet.db" );
SQLiteDatabase db = database_helper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put( "name", "tornadomeet" );
// 参数1为表名，参数2为更新后的值，参数3表示满足条件的列名称，参数4为该列名下的值
db.update("user1", values, "id=?", new String[]{"1" });
}
}
public class QueryOnClickListener implements OnClickListener{
public void onClick(View v) {
// TODO Auto-generated method stub
DatabaseHelper database_helper = new DatabaseHelper(MainActivity. this , "tornadomeet.db" );
SQLiteDatabase db = database_helper.getWritableDatabase();
// 查询的语法，参数1为表名；参数2为表中的列名；参数3为要查询的列名；参数时为对应列的值；该函数返回的是一个游标
Cursor cursor = db.query("user1", new String[]{"id", "name"}, "id=?", new String[]{"1"}, null , null , null );
// 遍历每一个记录
while (cursor.moveToNext()) {
String name = cursor.getString(cursor.getColumnIndex("name")); // 返回列名为name的值
System.out.println("query---->" + name);
}
}
}
public class DeleteOnClickListener implements OnClickListener{
public void onClick(View v) {
// TODO Auto-generated method stub
DatabaseHelper database_helper = new DatabaseHelper(MainActivity. this , "tornadomeet.db" );
SQLiteDatabase db = database_helper.getWritableDatabase();
// 直接删除名为tornadomeet对应的那条记录
db.delete("user1", "name=?" , new String[]{"tornadomeet" });
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true ;
}
}
2.DatabaseHelper.java
import android.content.Context;
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 VERSON = 1; // 默认的数据库版本
// 继承SQLiteOpenHelper类的类必须有自己的构造函数
// 该构造函数4个参数，直接调用父类的构造函数。其中第一个参数为该类本身；第二个参数为数据库的名字；
// 第3个参数是用来设置游标对象的，这里一般设置为null；参数四是数据库的版本号。
public DatabaseHelper(Context context, String name, CursorFactory factory, int verson){
super (context, name, factory, verson);
}
// 该构造函数有3个参数，因为它把上面函数的第3个参数固定为null了
public DatabaseHelper(Context context, String name, int verson){
this (context, name, null , verson);
}
// 该构造函数只有2个参数，在上面函数 的基础山将版本号固定了
public DatabaseHelper(Context context, String name){
this (context, name, VERSON);
}
// 该函数在数据库第一次被建立时调用
@Override
public void onCreate(SQLiteDatabase arg0) {
// TODO Auto-generated method stub
System.out.println("create a sqlite database" );
// execSQL()为执行参数里面的SQL语句，因此参数中的语句需要符合SQL语法,这里是创建一个表
arg0.execSQL("create table user1(id int, name varchar(20))" );
}
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
// TODO Auto-generated method stub
System.out.println("update a sqlite database" );
}
}
3.activity_main.xml
1 < RelativeLayout xmlns:android ="http://schemas.android测试数据/apk/res/android"
2 xmlns:tools ="http://schemas.android测试数据/tools"
3 android:layout_width ="match_parent"
4 android:layout_height ="match_parent" >
5
6 < Button
7 android:id ="@+id/create_database"
8 android:layout_width ="fill_parent"
9 android:layout_height ="wrap_content"
10 android:layout_alignParentBottom ="true"
11 android:text ="@string/create_database"
12 />
13
14 < Button
15 android:id ="@+id/update_database"
16 android:layout_width ="fill_parent"
17 android:layout_height ="wrap_content"
18 android:layout_above ="@id/create_database"
19 android:layout_alignParentLeft ="true"
20 android:text ="@string/update_database" />
21
22 < Button
23 android:id ="@+id/insert"
24 android:layout_width ="fill_parent"
25 android:layout_height ="wrap_content"
26 android:layout_above ="@id/update_database"
27 android:layout_alignParentLeft ="true"
28 android:text ="@string/insert" />
29
30 < Button
31 android:id ="@+id/update"
32 android:layout_width ="fill_parent"
33 android:layout_height ="wrap_content"
34 android:layout_above ="@id/insert"
35 android:layout_alignParentLeft ="true"
36 android:text ="@string/update" />
37
38 < Button
39 android:id ="@+id/query"
40 android:layout_width ="fill_parent"
41 android:layout_height ="wrap_content"
42 android:layout_alignParentLeft ="true"
43 android:layout_above ="@id/update"
44 android:text ="@string/query"
45 />
46 < Button
47 android:id ="@+id/delete"
48 android:layout_width ="fill_parent"
49 android:layout_height ="wrap_content"
50 android:layout_alignParentLeft ="true"
51 android:layout_above ="@id/query"
52 android:text ="@string/delete"
53 />
54
55 </ RelativeLayout >
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