midlet development j2me

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MIDPGUIDevelopment:

Alert,List,Form,TextBox JussiPohjolainen

TampereUniversityofAppliedSciences



DisplayableClassHierarchy

javax.microedi-on.lcdui javax.microedi-on.lcdui.game

Displayable

Alert List Form TextBox

Screen

Canvas GameCanvas



TextBox

• Togettheuserinput• TextBox a = new TextBox(String

title, String text, int maxSize,

int constraints)



TypesandFlags

• Types

– TextField.ANY – TextField.NUMERIC – TextField.DECIMAL – TextField.PHONENUMBER – TextField.EMAILADDR – TextField.URL

• Flags – TextField.PASSWORD

– TextField.UNEDITABLE

– TextField.NON_PREDICTIVE

– TextField.INITIAL_CAPS_WORD

– TextField.

INITIAL_CAPS_SENTENCE



TextBoxUsage

TextBox textbox =

new TextBox("Sähköposti",

"",

64,

TextField.EMAILADDR |

TextField.PASSWORD);





Displayable


Screen

Canvas GameCanvas



Alerts

• Therearetwotypesofalerts – TimedAlert

• Displayedcertainamountofme

– ModalAlert• Demandsuserconfirmaon

ModalAlert



Alert-class

• Constructor – public Alert(String title, StringalertText, Image alertImage, AlertType alerttype);!

• Methods – setTimeOut(...)! – setTimeOut(Alert.Forever)! – addCommand(...)!

• AlertTypes – ALARM, CONFIRMATION, ERROR, INFO,WARNING!





Displayable


Screen

Canvas GameCanvas



EXCLUSIVE,MULTIPLEandIMPLICIT



ConstrucngLists

• Whenyoucreatealist,youdefinelist's

– type(EXCLUSIVE,MULTIPLE,IMPLICIT)

– tle – stringelementsandimages(voluntary)

• API:– public List(String title, int type):

– public List(String title, int type, String [] stringelements, Image

[] imageElements);

• Scrollingisautomacallyavailable

• Itispossiblytoaddelementstothelistwithappend-

method.



ListExample1

public class MyList extends MIDlet{

private List mList;

public MyList() {

mList = new List(”Wanna Buy?”, Choice.MULTIPLE);

mList.append(“Herring”, null);

mList.append(“Goose Liver”, null);

mList.append(“Jelly”, null);

}

public void startApp() {

Display.getDisplay(this).setCurrent(mList);

}

public void destroyApp(boolean unconditional) {}

public void pauseApp() {}

}



ListExample2

public MyList() {

String [] elements =

{"hyytelöä", "kananmaksaa",

"ituja"};

mLista = new List("Haluatko

ostaa?", Choice.MULTIPLE,

elements, null);

}



AddingandRemovingListelements

• Itispossibletoaddandremovelistelements

• Theelementsareaccessiblebyindex(0...n)

• Replacingaelement:set(...)

• Addingelement:append(...)

• Addingelementtoacertainplace:insert(...)

• Findingelement:String getString(int n)

• Removingelement:void delete(int n)



MIDP2.0List

• Howdoyoutreattheelements,iftheydon't

fitintomobiledevice'sscreen?

– setPolicy(...);• Choice.TEXT_WRAP_ON,Choice.TEXT_WRAP_OFF,Choice.TEXT_WRAP_DEFAULT

• Changingthefont: – setFont(...)



ListSelecon

• Howtofindoutwhatelementuserselected? – public boolean isSelected(int i)! – public int getSelectedIndex()! – public void setSelectedIndex(int i, boolean s)!

• SeeListExample.java





Displayable


Screen

Canvas GameCanvas



IntrotoForm

• FormisaGUI-componentthatcanholdotherGUI

components

• TheseotheGUI-componentsarecalleditems.

• Iftherearemanyitems,theformwillprovidescrollingmechanism.

• Constructors: – public Form(String title)! – public Form(String title, Item[] items)!



HandlingItems

• AddingItemstotheForm: – Form a = new Form(“otsikko”);! – a.append(Item item);! – a.append(String str);! – a.append(Image image);!

• Everyitemhasanindex: – a.set(int index, Item item)! – a.insert(int index, Item item)! – a.delete(int index)!

• Othermethods: – int size();! – Item get(int index)!



SimpleExample

mForm = new Form("Otsikko");

mForm.append("moi");

mForm.append("hei");

mForm.append("tere");



UsingItems

• Therearemanyitems.

• javax.microedition.lcdui.Item:! – ChoiceGroup! – CustomItem // We will look this..! – DateField! – Gauge! – ImageItem // .. and this later! – Spacer! – StringItem ! – TextField!



ItemLayout

• EveryFormitemcanhavealayout:

– LAYOUT_LEFT! – LAYOUT_RIGHT! – LAYOUT_CENTER

! – ...!

• SeeAPI!



UsingItemLayout

StringItem layoutLeft = new StringItem("Layout: ", "LEFT");

layoutLeft.setLayout(Item.LAYOUT_LEFT);

StringItem layoutCenter = new StringItem("Layout: ", "CENTER");

layoutCenter.setLayout(Item.LAYOUT_CENTER);

StringItem layoutRight = new StringItem("Layout: ", "RIGHT");

layoutRight.setLayout(Item.LAYOUT_RIGHT);

mForm.append(layoutLeft);

mForm.append(layoutCenter);

mForm.append(layoutRight);



StringItem

• Representsasimple“Label”

Form form = new Form("Title");

StringItem st = new StringItem("Label: ";

"Value");

form.append(stringItem);



Item:Spacer

• Spacerprovidesemptyspaceintheform.

– Spacer empty = new Spacer(100,50); !



Item:TextField

• TextField: – public TextField(String label,String text, int

maxSize, intconstraints)!

• Constraints(sameasinTextBox) – ANY, NUMERIC,DECIMAL,PHONENUMBER,EMAILADDR, URL!

– PASSWORD, SENSITIVE;UNEDITABLE...!



Item:DateField

• DateandTimeinput. – public DateField(String label, int mode)! – public DateField(String label, int mode,TimeZone timezone)!

• mode – DATE, TIME, DATE_TIME!

• GetandSet-methods: – public Date getDate()! – public void setDate()!



DateFieldImages



Item:Gauge

• Gaugepresentsintegerinagraphicalform.– public Gauge(String label, boolean interactive,int maxValue, int initialValue)

• Byusingparameterinteracveitispossibletodefine

cantheusermodifythegauge.• InialValuecanalsobe:

• CONTINUOUS_IDLE !• INCREMENTAL_IDLE !• CONTINUOUS_RUNNING !• INCREMENTAL_UPDATING !



GaugeImages

Gauge kake1 = new Gauge("Editoitava", true, 100, 0);

Gauge kake2 = new Gauge("Ei-editoitava", false, 100,

50);

Gauge kake3 = new Gauge("INCREMENTAL_UPDATING",

false, Gauge.INDEFINITE,

Gauge.INCREMENTAL_UPDATING);

Gauge kake6 = new Gauge("CONTINUOUS_RUNNING",false, Gauge.INDEFINITE,

Gauge.CONTINUOUS_RUNNING);



Item:ChoiceGroup

• LikeList – public ChoiceGroup(String label,int choiceType, String []

elements, Image[] imageElements)!• Choicetype

– EXCLUSIVE! – MULTIPLE! – MIDP 2.0: POPUP!



ChoiceGroupImages

String [] lista = {"suomi", "ruotsi"};

ChoiceGroup choicegroup = new ChoiceGroup("Valitse

maa", Choice.POPUP, lista, null);



ItemsandEventHandling

• InsteadofusingCommandListeneryounow

useItemStateListener.

• Settheeventsourcetoformandthelistener

hastoimplementItemStateListenerinterface.• Theinterfacehasonlyonemethod:

– itemStateChanged(Item item)!• Example

midlet development j2me

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