android-database Operation A

Package com.yarin.android.Examples_06_05;


Import android.app.Activity;
Import android.content.ContentValues;
Import Android.database.Cursor;
Import Android.database.sqlite.SQLiteDatabase;
Import Android.graphics.Color;
Import Android.os.Bundle;
Import android.view.KeyEvent;
Import Android.widget.LinearLayout;
Import Android.widget.ListAdapter;
Import Android.widget.ListView;
Import Android.widget.SimpleCursorAdapter;


public class Activity01 extends activity {
private static int micount = 0;


/* Database Objects/*
Private sqlitedatabase msqlitedatabase = null;


/* Database name * *
Private final static String database_name = "EXAMPLES_06_05.DB";
/* Table name * *
Private final static String table_name = "Table1";


/* fields in table * *
Private final static String table_id = "_id";
Private final static String Table_num = "NUM";
Private final static String Table_data = "DATA";


/* Create a table SQL statement * *
Private final static String create_table = "CREATE TABLE" + table_name + ("+ table_id +" INTEGER PRIMARY KEY, "
+ Table_num + "Interger," + Table_data + "TEXT";


/* Linear Layout * *
LinearLayout m_linearlayout = null;
/* List View-display data in the database * *
ListView M_listview = null;


/** called the activity is a. */
@Override
public void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);


/* Create LinearLayout Layout Object * *
M_linearlayout = new LinearLayout (this);
/* Set the properties of the layout linearlayout * *
M_linearlayout.setorientation (linearlayout.vertical);
M_linearlayout.setbackgroundcolor (Android.graphics.Color.BLACK);


/* Create ListView Object * *
M_listview = new ListView (this);
Linearlayout.layoutparams param = new Linearlayout.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);


/* Set Display m_linearlayout layout * *
Setcontentview (m_linearlayout);


Open a database that already exists
Msqlitedatabase = this.openorcreatedatabase (database_name, mode_private, NULL);


Get the database phones cursor
try {
/* Create a table in database msqlitedatabase * *
Msqlitedatabase.execsql (create_table);
catch (Exception e) {
Updataadapter ();
}
}


public boolean onKeyUp (int keycode, keyevent event) {
Switch (keycode) {
Case Keyevent.keycode_dpad_left:
AddData ();
Break
Case Keyevent.keycode_dpad_right:
DeleteData ();
Break
Case Keyevent.keycode_1:
Updata ();
Break
Case keyevent.keycode_2:
Deletetable ();
Break
Case Keyevent.keycode_3:
DeleteDatabase ();
Break
}
return true;
}


/* Delete Database * *
public void DeleteDatabase () {
This.deletedatabase (database_name);
This.finish ();
}


/* Delete a table * *
public void deletetable () {
Msqlitedatabase.execsql ("DROP TABLE" + table_name);
This.finish ();
}


/* Update a piece of data * *
public void Updata () {
Contentvalues CV = new Contentvalues ();
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 the table * *
public void AddData () {
Contentvalues CV = new Contentvalues ();
Cv.put (Table_num, Micount);
Cv.put (table_data, "test database Data" + Micount);
/* Insert Data * *
Msqlitedatabase.insert (table_name, NULL, CV);
micount++;
Updataadapter ();
}


/* Delete the specified data from the table.
public void DeleteData () {


/* Delete Data * *
Msqlitedatabase.execsql ("DELETE from" + table_name + "WHERE _id=" + integer.tostring (micount));


micount--;
if (Micount < 0) {
Micount = 0;
}
Updataadapter ();
}


/* More lines trying to show * *
public void Updataadapter () {
Get the database phones cursor
Cursor cur = msqlitedatabase.query (table_name, new string[] {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 ListView and backstage data.
ListAdapter adapter = new Simplecursoradapter (This,
Define the display template for each row in the list
Indicates that each row contains two data items
Android. R.layout.simple_list_item_2,
Cursor Object for Database
Cur
Fetching data from the Table_num and table_data two columns of the database
New string[] {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 Processing * *
public boolean onKeyDown (int keycode, keyevent event) {
if (keycode = = Keyevent.keycode_back) {
/* When exiting, do not forget to close * *
Msqlitedatabase.close ();
This.finish ();
return true;
}
Return Super.onkeydown (KeyCode, event);
}
}