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.com/apk/res/android"
2 xmlns:tools="http://schemas.android.com/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>
布局文件
SQLite基本用法
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