Building a J2ME sliding menu with text and images(part-2)
In the given J2ME Menus example, we have explained to create two different
buttons that is going to perform as a back and forward buttons. You can see the
series of photographs one by one using these sliding menu in J2ME.
Code to create back and forward button images in J2ME
r_arrow = Image.createImage("/slide_arrow_right.png");
l_arrow = Image.createImage("/slide_arrow_left.png");
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To change the image as per our next event, we have created a function as
given below:
public void slideItem(int next){
if(!isImage() && select_index + next >= 0
&& select_index + next < labels.length){
back_index = select_index;
select_index += next;
time = System.currentTimeMillis();
}
}
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The Application is as follows:
Source Code of SlideMenu.java
import javax.microedition.lcdui.*;
public class SlideMenu{
public int select_index, back_index, width, height;
public Image r_arrow, l_arrow;
String[] labels = null;
Image[] icons = null;
public int duration = 500;
long time = 0;
public SlideMenu(String[] labels, Image[] icons, int width,
int height) throws Exception{
try{
r_arrow = Image.createImage("/slide_arrow_right.png");
l_arrow = Image.createImage("/slide_arrow_left.png");
}catch(Exception e){
e.printStackTrace();
}
this.width = width;
this.height = height;
this.labels = labels;
this.icons = icons;
}
public void slideItem(int next){
if(!isImage() && select_index + next >= 0 && select_index +
next < labels.length){
back_index = select_index;
select_index += next;
time = System.currentTimeMillis();
}
}
public boolean isImage(){
return back_index != select_index;
}
public void paint(Graphics g){
g.setColor(255, 0, 0);
g.fillRect(0, 0, width, height);
g.setColor(0, 0, 255);
if(select_index > 0){
g.drawImage(l_arrow, 2, height / 2,
Graphics.LEFT | Graphics.VCENTER);
}
if(select_index < icons.length - 1){
g.drawImage(r_arrow, width - 2, height / 2,
Graphics.RIGHT | Graphics.VCENTER);
}
g.drawString(labels[select_index], width / 2,
height - 2, Graphics.BOTTOM | Graphics.HCENTER);
g.setClip(l_arrow.getWidth(), 0, width - 2 *
l_arrow.getWidth(), height);
if(select_index != back_index){
int difference = (int)(System.currentTimeMillis() - time);
if(difference > duration){
difference = duration;
}
int image_present = select_index > back_index ? 1 : - 1;
int current_image = width / 2 - image_present *
difference * width / duration;
int next_image = current_image + width * image_present;
g.drawImage(icons[back_index], current_image, height / 2,
Graphics.VCENTER | Graphics.HCENTER);
g.drawImage(icons[select_index], next_image, height / 2,
Graphics.VCENTER | Graphics.HCENTER);
if(difference >= duration){
back_index = select_index;
}
}else{
g.drawImage(icons[select_index], width / 2, height / 2,
Graphics.VCENTER | Graphics.HCENTER);
}
}
}
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