Making a button press occur only once.

[Reality Check]

Alright I'm doing this little thing for school. Heres the code before I go further.

code:

var x, y, b : int var font : int := Font.New ("Palatino:24:bold,italic") setscreen ("offscreenonly") var bill : real := 0 loop     View.Update     locate (1, 1)     put bill     Mouse.Where (x, y, b)     drawfillbox (25, 90, 500, 15, brightred)     Font.Draw ("Children Under 12: $0.50", 55, 40, font, brightgreen)     drawfillbox (25, 175, 500, 100, brightred)     Font.Draw ("Students Under 18: $2.50", 55, 125, font, brightgreen)     drawfillbox (25, 260, 500, 185, brightred)     Font.Draw ("Adults 18-65: $5.00", 90, 208, font, brightgreen)     drawfillbox (25, 345, 500, 270, brightred)     Font.Draw ("Seniors over 65: $0.75", 75, 295, font, brightgreen)     if x > 24 and x < 501 and y > 14 and y < 89 then         drawfillbox (25, 90, 500, 15, brightblue)         Font.Draw ("Children Under 12: $0.50", 55, 40, font, brightred)         if b = 1 then             bill := bill + 0.50         end if     end if     if x > 24 and x < 501 and y > 99 and y < 176 then         drawfillbox (25, 175, 500, 100, brightblue)         Font.Draw ("Students Under 18: $2.50", 55, 125, font, brightred)         if b = 1 then             bill := bill + 2.50         end if     end if end loop

Now, on the top left corner of my screen is the bill. This is basically a computerized bill making machine for a play. Families come to a play and get the bill. The only 2 buttons that work right now are the children one and the student one but I didn't go further because of a problem I encountered. As you see I add the specified price to the variable 'bill' each time the mouse is clicked in the specified area. Now, take a look at the top left corner where I put the bill. It goes up by a lot more than just the specified price. I know why (because you can't click fast enough to make it true only once) How could I fix this?

[Martin]

It's like a machine gun. You click and hold, and bullets just keep coming out.

What you want is it to be like a pistol. You click, a bullet comes out, but you have to stop clicking and click again to shoot again.

So what you have to do is have a switch, like so (in pseudocode)

code:

has_clicked = false loop   If the mouse button is down and the mouse is over the button     if has_clicked is false       has_clicked = true       Do button action     end if   end if   if mouse button is up and has_clicked is true     has_clicked = false   end if end loop

It works like this.

has_clicked is false. The user clicks on the button. has_clicked is false, so the button's action happens. The next iteration of the loop, the button's still down, but has_clicked is true, so we know that we've already done the action. As soon as they lift up the button, has_clicked becomes false again and the user is free to click once more.

Cool?

[Reality Check]

Wow man thanks a lot. I'd give you bits if I knew how...

[Martin]

One thing you might want to do is make has_clicked become true if the button is clicked, regardless of if it's over the button. With the code I provided, clicking and dragging the mouse over the button will cause the button to click. So instead, try something like this:

code:

has_clicked = false loop   If the mouse button is down and the mouse is over the button     if has_clicked is false       Do button action     end if   end if   if the mouse button is down     has_clicked = true   elsif mouse button is up and has_clicked is true     has_clicked = false   end if end loop

[Reality Check]

^^Yea I was meaning to think of a way to do that too...you learn something new everyday!

[Martin]

Means it was a well spent day. I'm glad to be a help.

[Zacebdal]

For anyone else that is looking for an answer to this problem(i know i was). I just started using this a while ago but have figured a rather easy way to fix it. It has worked up to this point for me and it may not be the best but its what ive been using.

code:

var button, buttoncheck, x, y, shots : int shots := 0 loop     mousewhere (x, y, button)     if button = 1 and buttoncheck = 1 then         shots := shots + 1     end if     if button = 0 then         buttoncheck := 1     elsif button = 1 then         buttoncheck := 0     end if     put shots     delay (5)     cls end loop

This is just an example program. Just use the skeleton to make your own. Hope this helps, its a newbie approach but its kinda simple.