J2ME UI: Implementing a Progress Bar
first we create the Progress Bar object, the is is the simple part 
public class Gauge {
private int m_x, m_y, m_hight, m_width, m_Progress;
public void set(int x, int y, int height, int width ) {
m_x = x;
m_y = y;
m_height = height;
m_width = width;
}
public void setProgress(int progress){
m_progress= progress;
}
public void paint(Graphics g){
if(m_progress>=m_width)
return;
g.setColor(0);
g.drawRect(m_x, m_y-1, m_width, m_height+1);
g.setColor(GuiConstants.JAJAH_COLOR);
g.fillRect(m_x+1, m_y, m_Progress, m_height);
g.setColor(GuiConstants.LIST_BACK_COLOR);
if(m_width-m_Progress>0)
g.fillRect(m_Progress + m_x, m_y, m_width-m_Progress, m_height);
}
now we need to use it:
in order to display the Progress Bar, we will display it using a canvas. the canvas will hold a Progress Bar as a member, and it will display it. on that canvas more info can be displayed. note that on each progress update a repaint occurs. its sufficient to only repaint the progress bar or any updated UI.
public void run() {
try{
init();// init params
m_paintSuper = true;
repaint();
boolean run = !connection.callAllowed();// condition for running the bar
while(run){
for(int i= 1;i<m_gauge.getWidth()&& run;i++){
m_gauge.setProgress(i);
Thread.sleep(GAUGE_SPEED); // to make gauge slower
repaint();
run = !connection.callAllowed();
}
}
}
catch (Exception e) {
run();
}
}
protected void paint(Graphics g) {
// things that need to painted only once
if(m_paintSuper){
super.paint(g);
}
m_paintSuper = false;
}
m_gauge.paint(g);
}
now that we have the canvas ready with the Progress bar and the update of the progress we are left to display the canvas
if(m_gauge == null)
m_gauge = new GaugeView(null);
// sets the text for the canvas or any other thing to the canvas
m_Gauge.setText(str);
Display.getDisplay(m_midlet).setCurrent(m_gauge);
Thread t = new Thread(m_gauge);
t.start();
Tags: Canvas, Gauge, GUI, J2ME, Progress bar
