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Welcome back.

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In this lecture we're going to be learning a crucial service for scripting any kind of system relating

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to user input.

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This service is called the User Input Service.

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And it contains many functions and events that allow us to listen to a user's input on their local device.

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And since this service is purely for user input, it will only work within a local script.

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So to get access to this service, we can create a variable and I'm going to call it User Input Service.

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And we can go ahead and use the Get Service function and grab the user input service.

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And if we index the user input service, there is a plethora of different functions and properties and

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events, all relating to user input.

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For example, there's many Get functions that allow us to get things such as the mouse's location on

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the screen or the mouse delta.

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We can get the gamepad state.

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We can get current keys that are pressed down.

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We can check to see whether or not the player is focused inside of a text box on their screen, and

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a bunch of other neat functions.

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And of course, we also have a bunch of events in here.

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So for example, we can listen to when an input begins or an input ends.

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We can listen for touches on the screen or a tap in the world from a mobile device and things of that

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nature.

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The most important events that we're going to be taking a look at is going to be input began and input

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ended.

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So I'm going to index for input began.

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And then we can go ahead and connect a function to this event.

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And as you can see this function gets passed two different arguments.

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One is an input object and the other is a boolean.

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And this boolean lets us know whether or not this input was observed within a UI element.

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So for example, if a player touched a button on their screen, then this game processed event boolean

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would return true if a player just tapped randomly on their screen without touching any UI, then this

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boolean would be false.

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So we can go ahead and define those two parameters.

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I'll just call this first parameter input object, and then we can call the second boolean just processed.

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And this input object has several different properties that tell us some more information about this

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particular input that has began.

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For example, if there's a particular key that the player has pressed down on their keyboard, this

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property will tell us that we can get the type of the input, whether it's a mouse, a gamepad, if

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it's a touch on the screen, and so on.

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And then we can also get the state of the user input.

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And there's a few other properties like the delta and a position if applicable.

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So what we can do here is we can print out whether or not this input was processed.

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So I can just print something like was processed by UI.

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And then I'll just pass that process.

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Boolean.

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And then we can check some other things with this input object.

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For example, we can check if the input object dot user input type is let's say equal to the enum dot

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user input type.

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Let's say we want to listen to a left mouse click.

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So we can call that mouse button one.

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So if this input that has begun is equal to the left mouse button, then that means we know that the

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left mouse button is being held down.

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So we can put a print statement like mouse was held down.

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And of course we can continue on checking for different input.

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Maybe, for example, we want to check for a particular key that was pressed.

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Then we can check in our input object.

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If the key code is equal to, let's say the enum dot key code.

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And let's check maybe for the letter e.

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So if the key code is E, that means the player has the letter E being pressed down on their keyboard

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so we can print something like key E was held down.

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And this is for the input began event.

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So any time input begins, whether that's the player beginning to press down their mouse button or press

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down a key on their keyboard, or if it's a mobile player beginning to touch their screen, this is

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the event that's going to fire.

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And then we also have inside of the user input service input ended.

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And this is going to fire when it says right here when a user stops interacting with their device.

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So we can go ahead and connect a function to this as well.

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And this function is going to be passed the exact same arguments.

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So I'm actually just going to copy all of this.

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And then we can just paste that here.

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And again we can print whether or not this input ended event was processed by UI.

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We can check to see if it was the mouse button, one that got released or the input ended, and we can

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go ahead and change.

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The statement to mouse was released.

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And then the same thing goes for the E button on our keyboard.

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We can say key E was released.

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So now we can go ahead and playtest our game.

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And as you can see, we already got a print statement inside of our console, which is the input began

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event.

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And that's because as you can see, when my mouse enters and leaves, you can see this event keeps getting

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fired.

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And that's because it's detecting this new input where the game is going back and focus because my mouse

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is inside of the viewport.

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And then when my mouse leaves the viewport, as you can see, this event keeps firing.

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So that's one way you could use this event, is to detect whether or not the player has entered or left

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the viewport with their mouse, but some of the other events I want to go ahead and take a look at is,

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for example, clicking.

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So if I hold down my left mouse button, as you can see, we got the print statement, mouse was held

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down.

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And then of course I can click other buttons on my mouse.

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For example, I'm clicking a right click right now and as you can see that event keeps firing.

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So when I hold it down, it gets printed once.

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And then when I release it, it gets printed again because the input began and the input ended.

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Event is firing, and then I can go ahead and release my finger off of my left mouse button.

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And as you can see, we get mouse was released.

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I can go ahead and do the exact same thing for the letter E on my keyboard if I press other keys on

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my keyboard.

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As you can see, the input began and the input ended event are firing each time a key is pressed on

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my keyboard.

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So that's why we're getting so many of these print statements in the console.

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But if I go ahead and press down E on my keyboard, as you can see, key E was held down and then if

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I release it, there we go.

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Key E was released.

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So the user input service allows us to observe any type of input, whether it's on our keyboard or if

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it's with our mouse.

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We can also detect touches in our world from a mobile device as well.

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So let's go ahead and take a real quick look at how to do that.

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For example, in the user input service there is an event such as touch tap.

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And if you wanted to detect a tap in the world, then we also have an event for that which is touch

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tap in world.

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So let's go ahead and check that one out real quick.

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We can go ahead and connect a function to this.

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And this time we're going to get past two arguments, which is a position where we tapped on a screen,

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and the same boolean that tells us whether or not it was processed by UI.

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So we can go ahead and get this position.

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I'll just call it screen position.

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And then we'll just call it processed for the second argument.

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And then we can go ahead and print out in our console was processed by UI.

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And then we'll just pass our process variable here.

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And then we can print out something like uh screen tap at position.

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And then we'll just pass our screen position.

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Now I'm just going to comment out these other events.

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So that way we don't get a whole bunch of these print statements flooding our console.

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And then what we can do is we can go to our test tab.

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And we can go ahead and do some device testing emulation.

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So we're going to change this to device.

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Uh, I'll just have the iPad selected and then we can go ahead and play test our game.

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And here we are inside of our game.

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So if I go ahead and click with my mouse because this is emulated, it's going to fire that touch tap

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in world event.

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So if I click there we go.

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We get our screen tap at position 720 and 367.

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So that's defining the exact point where we tapped on our screen in pixels.

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So it appears studio is freaking out.

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I'm not sure why my mouse is stuck, but that's fine.

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As you can see, our event is firing for every time we click on our screen.

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Let me see if I can try to fix this and maybe tap somewhere else on the screen real quick.

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Okay.

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I got my mouse freed up.

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If I go ahead and tap something like maybe this button right here.

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As you can see, we're getting that same event fired.

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But this time the Boolean for that process, Boolean is telling us that it was processed by UI.

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And that's because we're clicking the jump button.

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But once we stop clicking the jump button and we just click in our world, as you can see, now we're

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getting false printed into the console because it's not being processed by any UI on the screen.

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For example, if I click my username up here, as you can see that boolean changes to true.

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Or if I click up here, that's also true.

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And then when I just start clicking randomly inside of the world, that boolean gets set to false.

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So the user input service is incredibly useful for listening to specific user inputs on a player's device.

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However, there is another service in the Roblox API that makes listening to input extremely simple

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and even allows us to support multiple different devices simultaneously without needing to write extra

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code to listen to each of those specific devices, like phones, computers, or consoles.

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This service is called the Context Action Service, and we'll be taking a look at it in the next lecture.

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See you there.