GUI Design in MIDPFENIL GANDHI ROLL NO. 105 MBA Tech I.T.

Introductiony Mobile Information Device Profile (MIDP) is a specification published

for the use of Java on embedded devices such as mobile phones and PDAs. y When combined with the Connected Limited Device Configuration (CLDC), MIDP provides a standard Java runtime environment for today's most popular mobile information devices, such as cell phones and mainstream personal digital assistants (PDAs).y AWT and SWING are not supported in MIDP, since y Limited resources in MIDP y No mouse y No Window

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Display0..1 0..n

Displayable

Command

Canvas

Screen

Graphic

Alert

List

TextBox

Form0..n

Item

TextField3

DateField

Gauge

ChoiceGroup

StringItem

ImageItem

y All MIDP GUI classes are in the lcdui

package import javax.microedition.lcdui.*; y Only one Displayable can be displayed, Screen or Canvas y Four kinds of Screeny Predefined Components List, Alert, and TextBox y Container Form

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Listy A list is a screen of choices y Three types of lists y Exclusive Choice List enables the user to select one and only one element y Multiple Choice List enables the user to select zero or more elements y Implicit List enables the user to select one element and execute an action on it

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y An example ListTest.javay Exclusive choice and multiple choice

y Add Commands to catch the conform events

List l = new List(List Test, Choice.EXCLUSIVE); l.append (Item 1, null);

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Alertsy An alert is a screen that gives users error messages or status

information y AlertTypey Alarm, Confirmation, Error, Info, Warning

y setTimeout(t) set the time for which the Alert is to be

shown y An example AlertTest.java

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TextBoxy Text boxes are editable screens that can display one or more

lines of text y Constructor TextBox(title, text, maxSize, constraints) y Constraintsy ANY, EMAIL_ADDR, NUMERIC, PASSWORD,

PHONENUMBER, URL, CONSTRAINT_MASK

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y An example TextBoxTest.java

new TextBox("TextBox ", "initial text", 256, TextField.ANY);

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Formsy A form is a screen that can contain an arbitrary mixture of

items: images, text fields, gauges, choice groups, and so on

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Form Itemsy Forms contain one or more items, each of which can have a

label y Itemsy StringItem, ImageItem, TextField, DateField, Guage,

ChoiceGroupy getLabel(), setLabel(label) defined in class Item

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y StringItems are similar to labels. y They have name or label and display string items. y StringItem StringItemTest.javay getText(), setText()

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y ImageItem

Provides layout control when Image objects are added to a Form or to an Alert ImageItemTest.javay Image Object

Image.createImage("/icons/Icon.png"); y ImageItem ImageItem(label string, image object, layout, atlText); y Item layout

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What's an Exception and Why Do I Care?y An exception is an event that occurs during the execution of

a program that disrupts the normal flow of instructionsy Throwing an exception y Exception handler

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Exception Handling in Javay What's an Exception and Why Do I Care? y Your First Encounter with Java Exceptions y Java's Catch or Specify Requirement y Dealing with Exceptions y Throwing Exceptions

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Catching and Handling Exceptionsy Specifying the exceptions thrown by a methody the try block y the catch block(s) y the finally blocktry { ... } catch (SomeThrowable variable) { Java statements } catch ( . . . ) { ... } finally { }16

y ChoiceGroup

A group of selectable elements intended to be placed within a Form ChoiceGroupTest.javay ChoiceGroup

new ChoiceGroup("ChoiceGroupTest", Choice.EXCLUSIVE) y Only EXCLUSIVE and MULTIPLE are allowed ChoiceGroupTest2.java new ChoiceGroup("ChoiceGroupTest", Choice.MULTIPLE)

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y TextField y Similar to previous TextBox y Gauge a bar graph display of a value intended for use in

a form GaugeTest.javay Constructor

Gauge(label, interactive, maxValue, initValue) y Methods setValue() getValue(value)18

y DateField an editable component for presenting date and

time information that may be placed into a Form DateFieldTest.javay Constructor

DateField(label, mode, timeZone)y Mode: DateField.DATE, DateField.TIME, and

DateField.DATE_TIME

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y Tiker - a piece of text that runs continuously across the

display TickerTest.javay Ticker can be add to any Screen except Canvas

f.setTicker(ticker) -- f is a form f.getTicker().setString(new string); y Methody setString(string), getString()

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Canvasy The Canvas class is a base class for writing applications that

need to handle low-level events and to issue graphics calls for drawing to the display y The Canvas extends from Displayable y Only one Displayable can be displayed, Screen or Canvas

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Event Delivery in Canvasy y y y y y y y y y

paint(Graphics g) showNotify() hideNotify() keyPressed() keyRepeated() keyReleased() pointerPressed() pointerDragged() pointerReleased() the CommandListener's commandAction() method

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Other Methods of Canvasy getHeight(), getWidth() y getGameAction(keyCode) y getKeyCode(gameAction) y repaint() y hasPointerEvents() y hasPointerMotionEvents() y hasRepeatedEvents() y isDoubleBuffered()

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Graphicsy For drawing graphics in Canvas y Setting methodsy setColor, setFont(), setGrayScale(), setStrokeStyle(), translate()

y Drawing methodsy drawChar(), drawChars(), drawString(), drawSubString(),

drawLine(), drawRect(), drawArc(), drawRoundRect(), fillArc(), fillRect(), fillRoundRect(), drawImage()

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Using Canvasy Define your own Canvas class by extending from class

Canvasy Override paint() for drawing graphics y Override event handling methods to handle low level events

y Use your own Canvas as previous Displayable classes y Instantiate your own Canvas object and set it to the display

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Checking Size of Canvasy yy y

MethodsgetHeight(), getWidth()

An exampleSizeCanvas.java SizeMIDlet.java

y yy

Two class in a MIDlet suite, but only one MIDlet drawString(string, x, y, anchor)Anchor =(LEFT, HCENTER, RIGHT) | ((TOP, BASELINE, BOTTOM)

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Coordination Systems of Canvasy Methodsy translate(x, y) translate origin to (x, y) y getTranslateX(), getTranslateY()

y An Exampley OrigTransCanvas.java y OrigTransMIDlet.java

int step = width/5; for(int i=1; i