J2ME Application Example - A simple calculator implementation (attachment code)
Using the low-level user interface, a simple calculator program based on the Nokia S60 series, I hope to help everyone. This article only contains program code, if you need a picture file and source code, please send me an email: cqucyf@263.net
The source code is as follows
// Calcmidlet.java
Package my.calc;
Import javax.microedition.midlet. *;
Import javax.microedition.lcdui. *;
Public class cagcmidlet extends midlet {
Private static cagcmidlet installation;
Private Calccanvas Calc = New Calccanvas ();
/ ** constructor * /
Public cagcmidlet () {
Instance = THIS;
}
/ ** main method * /
Public void startapp () {
Display.getdisplay (this) .SetCurrent (CALC);
}
/ ** Handle Pausing the MIDlet * /
Public void pauseApp () {
}
/ ** Handle Destroying the MIDlet * /
Public void destroyApp (boolean unconditional) {
}
/ ** quit the midlet * /
Public static void quitApp () {
Instance.destroyApp (True);
Instance.notifyDestroyed ();
Instance = NULL;
}
}
// Calccanvas.java
Package my.calc;
Import com.nokia.mid.ui.ffullcanvas;
Import javax.microedition.lcdui. *;
Import java.io. *;
/ **
* Calculator interface
*
Title: Calculator based on Nokia S60
*
description:
*
Copyright: Copyright (c) 2005
*
company:
* email: cqucyf@263.net
* @version 1.0
* /
Public Class Calccanvas Extends Fullcanvas {
/ ** Exit button * /
Private command cmdexit;
/**title*/
Private string title = "Calculator";
/ ** font * /
PRIVATE FONT F;
/ ** Digital * /
PRIVATE long result = 0;
/ ** Focus number * /
Private int Num = 0;
/ ** Focus coordinate * /
Private int focusx = 5;
PRIVATE INT FOCUSY = 52;
/ ** Button width interval * /
Private int intervalWidth = 2;
Private int interfaceHeight = 2;
/ ** picture starting coordinate * /
Private INT X = 10;
PRIVATE INT Y = 70;
/ ** Button size * /
Private int buttonWidth = 37;
Private int buttonHeight = 28;
/ ** image file * /
PRIVATE Image = NULL;
/ ** Store control represented content * /
Private char [] info = {'7', '8', '9', '/',
'4', '5', '6', '*',
'1', '2', '3', '-',
'0', '?', '=', ' '
}
/ ** The first number in the operation * /
Private long firstnum = 0;
/ ** The second number in the operation * /
PRIVATE long secondnum = 0;
/ ** Do you enter the first number, True represents have entered, FALSE does not enter * /
PRIVATE BOOLEAN flag = false;
/ ** Store the subscript of the prescribed arithmetic button * /
Private int func = 0;
/ ** Default constructor * /
Public cagccanvas () {
Try {
Image = image.createImage ("/ CALC.PNG");
//System.out.println (X);
} catch (ioexception e) {
// ignore
System.out.println (e);
}
}
/ **
* Draw
* @Param G graphic object
* /
Public void paint (graphics g) {
/ ** Clear the current display * /
G.SetColor (255, 255, 255);
G.fillRect (0, 0, getWidth (), getHeight ());
// Restore system color
G.SetColor (0,0,0);
f = g.getfont ();
// Draw the title
g.drawstring (title, getwidth () / 2, f.getHeight () / 2, graphics.top | graphics.hcenter;
// Draw a text box
g.drawRect (3, 24, 172, 20);
// Draw a number
String temp = long.toString (result);
g.drawstring (Temp, getWidth () - 3, 30, graphics.top | graphics.right);
// Draw panel
G.DrawImage (Image, 2, 50, graphics.top | graphics.Left);
// Draw a focus
Drawfocus (g, num);
}
/ **
* Event processing
* @Param KeyCode button value
* /
Public void keypressed (int keycode) {
//System.out.println (Keycode);
/ / Move left to the left, if you move to the right boundary, move to the next line
if (Keycode == KEY_LEFT_ARROW) {
/ / Judgment whether to reach the last one
IF (NUM == 0) {
Num = 15;
} else {
Num--
}
}
/ / Move right to right, if moved to the left boundary, move to the end of the previous line
IF (Keycode == key_right_arrow) {
/ / Judgment whether to reach the first
IF (NUM == 15) {
Num = 0;
} else {
Num ;
}
}
/ / Move up, if moved to the upper boundary, move to the lower boundary corresponding location
if (Keycode == Key_up_arrow) {// Determines if it moves to the upper boundary, if it is the corresponding position to the lower boundary
IF (NUM - 4 <0) {
NUM = 15 Num - 3;
} else {
Num = NUM - 4;
}
}
/ / Move down, if moved to the lower boundary, move to the upper boundary corresponding location
IF (Keycode == KEY_DOWN_ARROW) {
/ / Judgment whether to reach the lower boundary, if it is moved to the corresponding position of the upper boundary
IF (NUM 4> 15) {
Num = NUM 3 - 15;
} else {
Num = NUM 4;
}
}
//Confirm button
IF (Keycode == -5) {
/ / Operation according to the different button
Action ();
}
//System.out.println ("num: " Num);
// Draw
Repaint ();
}
/ **
* Draw a focus rectangle
* @Param G graphic object
* @Param NUM Focus number
* /
Private void DrawFocus (Graphics G, Int Num) {
/ / Set the color of the color is red
G.SetColor (255, 0, 0);
/ / Set the X and Y coordinates of the focus
SetxandyBynum (NUM);
// Draw the selection box
g.drawRect (Focusx, Focusy, ButtonWidth, ButtonHeight);
}
/ **
* Set the X and Y coordinates of focus according to focus
* @Param NUM Focus number
* /
Private void setxandyBynum (int Num) {
FOCUSX = 5 (Num% 4) * (ButtonWidth Intervalwidth);
FOCUSY = 52 (Num / 4) * (ButtonHeight IntervalHeight);
}
/ **
* After the user presses the OK button, operate according to the different button
* /
Private void action () {
/ / Judgment the focus button is a number
IF ((NUM> = 0 && Num <3) || (Num> 3 && Num <7) || (Num> 7 && Num <11) || (NUM == 12)) {
// If you are a number, multiply the original number by 10, plus the current number
Result = Result * 10 (Info [NUM] - '0');
}
/ / If the negative is pressed, the negative number of the current number is
IF (Num == 13) {
Result = -Result;
}
/ / Judgment whether the first number is input
IF (Flag == true) {
Secondnum = result;
// Process function button
/ / Press the = button, or press the operation button to calculate
IF (NUM == 14 || (Num% 4 == 3)) {
/ / According to the calculation button
IF (Func == 3) {
// divide the method
Result = firstnum / secondnum;
} else if (func == 7) {
// Multiplication
Result = firstnum * secondnum;
} else IF (func == 11) {
// subtracting calculation result = firstnum - secondnum;
Else IF (func == 15) {
// addition operation
Result = firstnum secondnum;
}
IF (NUM == 14) {
// Assign the calculation result to the first number
Firstnum = result;
/ / Modify the flag to false
Flag = false;
} else {
// Record the operation button
Func = NUM;
// Assign the calculation result to the first number
Firstnum = result;
// will display clear
Result = 0;
}
}
} else {
// Assign the current value to the first number
Firstnum = result;
/ / Determine if the operation button is pressed and store the prescribed operation button
IF (NUM% 4 == 3) {
Func = NUM;
/ / Set the first number has been entered, and will display clear
Flag = true;
Result = 0;
}
}
}
}
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