Android-sqlite Database _ Open an existing database operation demo

Code

 Packagecom.lxt008;ImportCOM.LXT008.R;Importandroid.app.Activity;Importandroid.content.ContentValues;ImportAndroid.database.Cursor;Importandroid.database.sqlite.SQLiteDatabase;ImportAndroid.graphics.Color;ImportAndroid.os.Bundle;Importandroid.view.KeyEvent;Importandroid.widget.LinearLayout;ImportAndroid.widget.ListAdapter;ImportAndroid.widget.ListView;ImportAndroid.widget.SimpleCursorAdapter; Public classActivity01extendsactivity{Private Static intMicount = 0; /*database Objects*/    PrivateSqlitedatabase msqlitedatabase =NULL; /*Database name*/    Private Final StaticString database_name = "Examples_06_05.db"; /*Table name*/    Private Final StaticString table_name = "Table1"; /*fields in the table*/    Private Final StaticString table_id = "_id"; Private Final StaticString table_num = "NUM"; Private Final StaticString table_data = "DATA"; /*to create a table's SQL statement*/    Private Final StaticString create_table = "CREATE TABLE" + table_name + "(" + table_id + "INTEGER PRIMARY KEY," + Table_num + "INTER GER, "+ Table_data +" TEXT) "; /*Linear Layout*/LinearLayout m_linearlayout=NULL; /*List View-display data in a database*/ListView M_listview=NULL; /**Called when the activity is first created.*/@Override Public voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate); /*creating a LinearLayout Layout object*/M_linearlayout=NewLinearLayout ( This); /*to set the properties of a layout linearlayout*/m_linearlayout.setorientation (linearlayout.vertical);        M_linearlayout.setbackgroundcolor (Android.graphics.Color.BLACK); /*Create a ListView object*/M_listview=NewListView ( This); Linearlayout.layoutparams param=Newlinearlayout.layoutparams (LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);        M_listview.setbackgroundcolor (Color.Black); /*add M_listview to M_linearlayout layout*/M_linearlayout.addview (M_listview, param); /*Setting the display m_linearlayout layout*/Setcontentview (m_linearlayout); //open a database that already existsMsqlitedatabase = This. openorcreatedatabase (database_name, mode_private,NULL); //gets the cursor of the database phones        Try        {            /*Create a table in the database Msqlitedatabase*/Msqlitedatabase.execsql (create_table); }        Catch(Exception e) {updataadapter (); }    }     Public BooleanOnKeyUp (intKeyCode, KeyEvent event) {        Switch(keycode) { CaseKeyEvent.KEYCODE_DPAD_LEFT:AddData ();  Break;  CaseKeyEvent.KEYCODE_DPAD_RIGHT:DeleteData ();  Break;  CaseKeyEvent.KEYCODE_1:UpData ();  Break;  CaseKeyEvent.KEYCODE_2:DeleteTable ();  Break;  CaseKeyEvent.KEYCODE_3:DeleteDataBase ();  Break; }        return true; }

    /*Deleting a database*/     Public voidDeleteDatabase () { This. DeleteDatabase (database_name);  This. Finish (); }    /*Delete a table*/     Public voiddeletetable () {Msqlitedatabase.execsql ("DROP TABLE" +table_name);  This. Finish (); }    /*update One piece of data*/     Public voidUpdata () {contentvalues CV=Newcontentvalues ();        Cv.put (Table_num, Micount); Cv.put (Table_data,"Modified data" +micount); /*Update Data*/msqlitedatabase.update (TABLE_NAME, CV, Table_num+ "=" + integer.tostring (miCount-1),NULL);    Updataadapter (); }    /*add a piece of data to a table*/     Public voidAddData () {contentvalues CV=Newcontentvalues ();        Cv.put (Table_num, Micount); Cv.put (Table_data,"Test database Data" +micount); /*Inserting Data*/Msqlitedatabase.insert (table_name,NULL, CV); Micount++;    Updataadapter (); }    /*deletes a specified piece of data from a table*/     Public voidDeleteData () {/*Delete Data*/Msqlitedatabase.execsql ("DELETE from" + table_name + "WHERE _id=" +integer.tostring (Micount)); Micount--; if(Micount < 0) {Micount= 0;    } updataadapter (); }    /*more rows try to show*/     Public voidUpdataadapter () {//gets the cursor of the database phonesCursor cur = msqlitedatabase.query (table_name,NewString[] {table_id, table_num, Table_data},NULL,NULL,NULL,NULL,NULL); Micount=Cur.getcount (); if(cur! =NULL&& cur.getcount () >= 0)        {            //ListAdapter is a bridge between the ListView and background dataListAdapter adapter =NewSimplecursoradapter ( This,            //define a display template for each row in the list//indicates that each row contains two items of dataAndroid. R.layout.simple_list_item_2,//cursor Object for databasecur,//fetching data from Table_num and table_data two columns in the database                Newstring[] {table_num, table_data},//Views corresponding to name and number                New int[] {Android. R.id.text1, Android.            R.ID.TEXT2}); /*Add adapter to M_listview*/M_listview.setadapter (adapter); }    }    /*Key Event Handling*/     Public BooleanOnKeyDown (intKeyCode, KeyEvent event) {        if(KeyCode = =keyevent.keycode_back) {            /*when exiting, don't forget to close*/Msqlitedatabase.close ();  This. Finish (); return true; }        return Super. OnKeyDown (KeyCode, event); }}

Layout file

<?XML version= "1.0" encoding= "Utf-8"?><LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"android:orientation= "vertical"Android:layout_width= "Fill_parent"Android:layout_height= "Fill_parent"    ><TextViewAndroid:layout_width= "Fill_parent"Android:layout_height= "Wrap_content"Android:text= "@string/hello"    /></LinearLayout>

Android-sqlite Database _ Open an existing database operation demo