swing and joptionpane

SwingandJOptionPane

Producedby:

DepartmentofComputingandMathematicshttp://www.wit.ie/

UsingGraphicalUserInterface(GUI)Components

Dr.Siobhán DrohanMr.ColmDunphyMr.DiarmuidO’Connor

GraphicalUser

Interface(GUI)

Topicslist

Swing• JOptionPane– JOptionPane methods• showMessageDialog()• showInputDialog()• showConfirmDialog()

WhatisSwing?

• Swing isasetofprogramcomponentsfor Java programmersthatallowyoutocreategraphicaluserinterface(GUI )components

WhatisSwing?

• Swing isasetofprogramcomponentsfor Java programmersthatallowyoutocreategraphicaluserinterface(GUI )components

Thismodule:

dialog/messageboxesonly

UsingSwing– import thelibrary

• WemakeSwingcomponentsavailabletousbyimportingtheSwingcomponentsatthestartoftheprogram.

import javax.swing.*;

However,* importsall theSwingcomponents(andtherearealot!)

UsingSwing– import specifics

• WemakeSwingcomponentsavailabletousbyimportingtheSwingcomponentsatthestartoftheprogram.

import javax.swing.JOptionPane;

AsweonlyplanonusingJOptionPane,wecanjustimportthatspecificSwingcomponentinsteadoftheentirelibrary.

UsingJOptionPane withSwing

• HavingimportedJOptionPane fromSwing,wecanusethesemethods:

showMessageDialog()• Simplemessageoutput

showInputDialog()• Allowsusertotypein(string)input

showConfirmDialog()• Allowtheusertochooseanoption

JOptionPane.showMessageDialog (null, "Welcome to the 12 days of Christmas”

);

showMessageDialog - SimpleMessageoutput

TextinDialogbox

ParentComponent– forourpurposes,null willworkasfirstparameter.

https://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html

JOptionPane.showMessageDialog (null, "Welcome to the first day of Christmas”,“Christmas Title”,JOptionPane.PLAIN_MESSAGE);

showMessageDialog - Messageoutputwithlabel

Thismeans‘noicon’https://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html

Textfortitle ofbox

String day = JOptionPane.showInputDialog("Welcome to Christmas week\n\n " + "Please enter the day: ","Monday");

showInputDialog - Messageinput

Prompttext


Defaultvalue

ReadinginnumbersviaJOptionPane

• Problem:– showInputDialog() returnsaString– Soifyoutype22,itisthestring“22”,thiscan’tbeusedasnumber

• Solution– Useapredefinedmethodtoconverttoanumber.

int number = Integer.parseInt ("22");println (number + 3);

printsthenumber25.

UsingparseInt withinput

ThisconvertstheinputStringtoanIntegerandstoresitinnum.https://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html

int num = Integer.parseInt ( JOptionPane.showInputDialog(

"Enter a number between 0 and 10", "3" ));

showConfirmDialog - UsingtheYes/No option

int reply = JOptionPane.showConfirmDialog(null, “Did you watch the Late Late Toy Show on Saturday night?","Christmas Question", JOptionPane.YES_NO_OPTION );


JOptionPane.YES_OPTION isreturnedifyoupress‘Yes’.JOptionPane.NO_OPTION isreturnedotherwise.(replywillbeassignedthisvalue)

Summary

Swing• JOptionPane

– import javax.swing.JOptionPane;

– JOptionPane methods• showMessageDialog()• showInputDialog()

– parseInt()

• showConfirmDialog()– JOptionPane.YES_NO_OPTION– JOptionPane.YES_OPTION– JOptionPane.NO_OPTION

Questions?

swing and joptionpane

Documents