Start and Stop

Okay so we made our buttons, and I said we can give them commands. 0:00 Right now they don't have any commands. 0:04 So, let's give them a command to run whenever they're clicked, all right? 0:05 So, we need a new method that's gonna run when the start button is clicked, 0:11 we need one when the stop button is clicked. 0:15 So let's go down here, and down here at the bottom. 0:18 I mean, we're done building stuff for right now. 0:24 We got a banner, we got a timer. 0:26 Yeah, we don't need to build anything else. 0:28 All right, this is gonna be run when we start the timer. 0:29 So let's call it start timer, all right. 0:32 I mean, why be creative if we don't have to be. 0:35 Okay, so, the first the we wanna do is we wanna make sure 0:37 every time we start the timer, the timer is set back to the full length. 0:40 So we're gonna repeat the line at center init method, 0:45 which means really we don't have to do the line and the init method. 0:48 You could leave that out if you wanted to, and 0:52 this also means that we don't have a pause function on our timer. 0:56 It's always gonna be 25 minutes when you hit start on it, and that's fine. 0:59 We don't have to have a pause button we can just always be like all right, 1:03 we started at the beginning and we stop, 1:05 if we have to go do something other than work. 1:08 If you want to add your own pause button, or your own pause functionality to this, 1:10 where it just holds onto the time, 1:14 if the time's not zero then it starts back wherever it's at, go for it. 1:16 That is a wonderful addition to add to this. 1:19 Before we get too far into this, I want there to be a variable 1:21 that's tracking whether or not the timer is running, right? 1:24 So we know how much time is left, 1:27 but we don't know if we should actually be decrementing from that time or not. 1:28 So back up here in init, we just jump all around don't we. 1:32 Let's add a new thing here that's self.running, and 1:37 that's gonna be equal to false to begin with, well how do I set it to true? 1:40 False, because when our app starts the timer is not running. 1:44 All right, but back down here in start timer. 1:47 Here we go, we want running to now be equal to true right, 1:53 where we started the timer. 1:57 So, running is now true. 1:59 Okay, so go right back up here, and 2:00 in our start button, command is gonna 2:05 be equal to self.start timer. 2:10 And we don't need the parentheses on there, 2:14 because it will call the function when the button gets clicked. 2:16 Okay, that's all we have to do for the start button for right now. 2:20 We've got a couple more things to do in a minute, but that's it for right now. 2:23 Let's do the stop button. 2:27 Guess what, it works the same way. 2:28 Let's go ahead and add this in, command=self.stop_timer_. 2:29 All right, and then down here stop_timer, and what do we want this to do? 2:35 So what we want stop_timer to do is we want it to set 2:42 self.running equal to false and that's it. 2:47 We just want it to stop, it's no longer running. 2:52 We're not running anymore. 2:54 All right, so that's all we gotta do. 2:55 Let's run this real quick. 2:59 Ctrl+R, bring this over here. 3:01 I hit start, I hit stop. 3:04 Anybody know what's going on? 3:07 I mean the commands are running, I'm sure. 3:08 Let's add this in, let's do, come up here we'll say print started, 3:11 and then here we'll do print, stopped. 3:17 Run it again, and we hit start, see now it's started, 3:21 we hit stop and there it stopped. 3:26 All right, so the commands are working, but we don't know if the commands worked, 3:29 there's nothing showing us that the commands worked. 3:33 So buttons have a fun little thing called button state. 3:37 I think it'd be better if our UI told us whether button could be clicked or 3:41 not right, because you don't want to click the stop button when it's already stopped, 3:45 and you don't wanna click the start button when it's already running. 3:49 So, let's make it to where the buttons can't be done that way. 3:53 So, let's go back up here to our build buttons. 3:57 There's where we put our buttons into our grid, and 4:01 let's make sure that the stop button is disabled by default, 4:04 because at the beginning, all you can do is hit start, right? 4:09 So self.stop_button.config, 4:11 see, and the state is gonna be tkinter.DISABLED. 4:16 All caps for disabled there. 4:23 Okay, so, at the beginning the buttons disabled, let's look at that. 4:26 Here we go you can see I can't click the stop button at all. 4:32 I can click the start button now, but I can't click stop. 4:35 Okay, so great, and the nice thing is down here in this, 4:38 since we have our buttons registered to self, we can get to them. 4:44 So when someone clicks start, we want to do 4:47 self.stopbutton.config(state=tkinter.DEFA- ULT), 4:51 which is just the raised up you can click it thing. 4:58 And self.startbutton.config(state=tkinter.DIS- 5:04 ABLED), because the stop button should be disabled at that point, okay. 5:09 And then, take these two lines bring them right down here, and 5:15 we want to basically swap these. 5:19 We want the start button, stop button, sorry, to be disabled, and 5:20 we want the start button to be back to default. 5:25 I'm sorry, it's not default, it's normal. 5:29 I thought default sounded weird. 5:36 All right, so it's normal. 5:38 So, we click start, stop. 5:40 They trade back and forth. 5:43 All right, cool. 5:46 Nothing else is happening though, because nothing else is happening. 5:48 I mean, the running variable changes, but that's about it. 5:52 So, we need to do some polling. 5:55