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The controlling script for the clock digits looks like this:
// Digit.java
import java.awt.*;
import java.util.*;
import linguist.quickshow.*;
public class Digit extends Actor
{
Digit(Stage stage,int id)
{
super(stage,"Digit",id);
}
public void run()
{
int left=0;
switch (getID())
{
case 0: left=18; break;
case 1: left=60; break;
case 2: left=130; break;
case 3: left=172; break;
}
loadImageSequence("gif/D2-","0","9",".gif",left,20);
setCurrentView(0);
show();
setReady();
new DigitModifier(this);
int min=-1;
addMouseListener(new ActorAdapter()
{
public void mousePressed(Actor a)
{
Color c=Color.black;
switch (getID())
{
case 0: c=Color.red; break;
case 1: c=Color.green; break;
case 2: c=Color.blue; break;
case 3: c=Color.gray; break;
}
postMessage("Background","color",c);
}
});
while (true)
{
pause(1000);
Date d=new Date();
int m=d.getMinutes();
if (m!=min)
{
int view=0;
switch (getID())
{
case 0: view=d.getHours()/10; break;
case 1: view=d.getHours()%10; break;
case 2: view=d.getMinutes()/10; break;
case 3: view=d.getMinutes()%10; break;
}
setCurrentView(view);
min=m;
}
}
}
}
This class requires an ID for its constructor, which identifies which digit is being referred to. Two switch() statements then provide all the code that differs from one digit to another,
viz. the position of the digit and the source of its data.
When a digit is clicked the class posts a message to the Background Actor telling
it to change colour. This illustrates a key feature of QuickShow; there's usually
no need to expose the methods of your Actor subclasses. Instead, send them messages and
let them call their own methods. You'll find this will avoid a lot of unnecessary casting. The only exception is
where performance is an issue; processing text messages is more time-consuming.
The methods postMessage() and sendMessage()
do much the same thing, but the former causes the message to be sent to the Actor in a new thread, allowing processing
to continue without waiting for a reply. In contrast, sendMessage() waits
for the message to be received and acted upon. It also returns an Object containing any data the called Actor might
have supplied. Use postMessage() wherever possible as it makes better use
of threads, but don't make any assumptions about the order in which messages are processed. If you need to be sure
of the order, use sendMessage().
Note that the code that causes the digits to shrink and grow is nowhere to be seen. In fact, it's handled by
the DigitModifer object, to which we pass our Actor so it knows which digit to
mess about with.
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