[1.15.2] How to check if a key is double tapped

[squidlex]

I want to check if the default move back key is double tapped. I've tried looking into how Minecraft handles sprinting but I can't find the actual check for a double tap.

 

Thanks for your help!

[Turtledove]

I've done similar for dashing side to side. I set up a tick handler where I detect if the player has pressed the movement key once, and if it's pressed again within a certain number of ticks, then execute. Use the input handler event, and send a packet to server to do the logic there.

[squidlex]

28 minutes ago, Turtledove said:

I've done similar for dashing side to side. I set up a tick handler where I detect if the player has pressed the movement key once, and if it's pressed again within a certain number of ticks, then execute. Use the input handler event, and send a packet to server to do the logic there.

Thanks for the reply!

[squidlex]

Is anyone aware of an alternate method to this? I'd imagine it works but I'm getting some odd behaviour in using both onKeyPressed() and isKeyDown() whilst using a boolean flag to make it only fire once. I've tried this in KeyInputEvent, ClientTickEvent and PlayerTickEvent. The issue is that when I hold down the key it will fire randomly at times and act as a double press.

 

Edit: I tried onKeyPressed() by itself, and seperately tried isKeyDown() whilst using a boolean flag.

Edited April 30, 2020 by squidlex
Clarification

[squidlex]

On 4/30/2020 at 4:43 PM, Turtledove said:

I've done similar for dashing side to side. I set up a tick handler where I detect if the player has pressed the movement key once, and if it's pressed again within a certain number of ticks, then execute. Use the input handler event, and send a packet to server to do the logic there.

Hi again, sorry to be a pain but do you have any source code I can look at? I'm having some issues with this firing multiple times. No worries if not

[superminerJG]

The reason this happens is if you hold the key for long enough, it starts to send repeated keydown inputs. So that's why the boolean is necessary.

 

like if i held down k for long it does this:

kkkkkkkkkkkkkkkkkkkkkkkkk

[squidlex]

2 hours ago, superminerJG said:

The reason this happens is if you hold the key for long enough, it starts to send repeated keydown inputs. So that's why the boolean is necessary.

 

like if i held down k for long it does this:

kkkkkkkkkkkkkkkkkkkkkkkkk

Thanks for the replying, how did you go about implementing your boolean? I tried using one as so

if (Minecraft.getInstance().gameSettings.keyBindLeft.isKeyPressed && notPressed) {
				if (timer > 0) {
					timer = 0;
					// Do something from double tap
				} else {
				timer = 10;			
		}
 			notPressed = false;
	} else if(!Minecraft.getInstance().gameSettings.keyBindLeft.isKeyPressed) {
	notPressed = true; }
				

This however never fired.

[superminerJG]

class Ticker extends ITickable{
  static int timer = 0;
  static boolean pressed = false;
  static boolean doublePressed = false;
  static void tick() {
    if (Minecraft.getInstance().gameSettings.keyBindLeft.isKeyDown()) {
      if (!pressed) {
        if (timer < 8) {
          doublePressed = true;
        }
        timer = 10;
        pressed = true;
      }
      if (doublePressed) {
        //do stuff
      }
    }
    else {
      pressed = false;
      if (doublePressed) {
        doublePressed = false;
        timer = 0;
      }
    }
    timer--;
  }
}

I honestly don't know if this will work, but this is how I think it should work. Obviously you can improve on this, but the idea is to make sure that the second press doesn't happen too soon.

[squidlex]

14 hours ago, superminerJG said:

class Ticker extends ITickable{
  static int timer = 0;
  static boolean pressed = false;
  static boolean doublePressed = false;
  static void tick() {
    if (Minecraft.getInstance().gameSettings.keyBindLeft.isKeyDown()) {
      if (!pressed) {
        if (timer < 8) {
          doublePressed = true;
        }
        timer = 10;
        pressed = true;
      }
      if (doublePressed) {
        //do stuff
      }
    }
    else {
      pressed = false;
      if (doublePressed) {
        doublePressed = false;
        timer = 0;
      }
    }
    timer--;
  }
}

I honestly don't know if this will work, but this is how I think it should work. Obviously you can improve on this, but the idea is to make sure that the second press doesn't happen too soon.

Thanks for the code I really appreciate it! For some reason even with this code, which I agree should definitely work, it constantly outputs that it has been double pressed. Thanks for your help though

[SwiftNinjaPro]

I think I figured It Out. (note: in my mod, I added my own methods to detect inputs, so the code may need to be modified)

 

This method only runs the key detection function once, than waits for the key to be released before allowing it to run again. This means it should not return a double press if the user holds the key down. It also will not trigger, if the key is double tapped too slow (so the user pressing the key once, than pressing it again 10 minutes later, will Not trigger a double tap).

 

long startTime = System.currentTimeMillis();
boolean moveKeyPressed = false;
boolean keyEnabled = false;

@SubscribeEvent
public void onMove(InputUpdateEvent event){
  boolean keyPressed = event.getMovementInput().backKeyDown;
  
  if(!keyEnabled){
    if(!moveKeyPressed && keyPressed){
      long now = System.currentTimeMillis();
      
      if(now > startTime + 300){
      	startTime = now;
      }else{
      	keyEnabled = true;
        // do stuff on double tap...
      }
      
      moveKeyPressed = true;
    }else{ // optional
      if(!moveKeyPressed && keyPressed && System.currentTimeMillis() > startTime + 300){
        keyEnabled = false;
        // do stuff to cancel double tap action if key is pressed again...
        // useful if you need to allow the player to override the keypress and cancel the double tap action
      }
    }
    
    // detect key release
    if(!keyPressed){
      moveKeyPressed = false;
    }
  }
}

 

Edited December 17, 2020 by SwiftNinjaPro
Modified math a bit