Behaviors are connected together with events to form more complex behaviors. In this simple example, pressing the y button on the joystick will trigger a change in the active behavior from driving the robot with an an arcade style input to driving the robot with a tank style input.
The event class implements the event interface. The methods onTransition(), isTriggered(), and getToBehavior() are used by the behavior. Each method has a purpose in the framework as follows:
- onTransition() runs only when the event is triggered resulting in a transition between behaviors. The order of transitions are set in the behaviors class. This will be covered in the part 3.
- isTriggered() returns a boolean value. If the Boolean is True, the transition occurs.
- getToBehavior() is used by the framework when it requests the destination behavior.
To use this behavior, copy the Event_Template shown below into a new class name. I start the name of all of my event classes with the name Event_xx. This naming convention helps when our team shares events for use in different programs. Here is a copy of the template:
package com.qualcomm.ftcrobotcontroller.geekmybot; /** * Created by David Lempia on 8/2/2015. * * Copy this template and rename it with the name of your event. i.e. Event_ButtonX. * Inputs and Outputs are put in the Behaviors_xx file. Access them using gd.xx * Add the event to the Behaviors_xx file. * Add inputs and outputs to the Behaviors_xx file. * Pass parameters in through the Event_Template Constructor. */public class Event_Template implements Event { private Behavior toBehavior; // Returning true triggers the event // Pass variables public boolean isTriggered(){ return(false); } // This runs if the event is triggered public void onTransition(){ } // Change Behaviors_XX to the name of your behaviors class // Add parameters as needed GlobalData gd; Event_Template(GlobalData gd, Behavior toBehavior){ this.gd=gd; this.toBehavior = toBehavior; } // No change needed public Behavior getToBehavior() { return(this.toBehavior); } }
To create an event that transitions whenever the Y joystick button is pressed, add a new RiseEdgeTrigger to the constructor. Check for a button press in the isTriggered() method. Here is what the final sofware looks like for the Event_ButtonY.java class:
package com.qualcomm.ftcrobotcontroller.geekmybot; /** * Created by David Lempia on 8/2/2015. */public class Event_ButtonY implements Event { // Returning true triggers the event public boolean isTriggered(){ boolean button_pressed = pressed.calculate(gd.buttonY); return(button_pressed); } // This runs if the event is triggered public void onTransition(){ } // No change needed RiseEdgeTrigger pressed; private Behavior toBehavior; GlobalData gd; Event_ButtonY(GlobalData gd, Behavior toBehavior){ this.gd = gd; this.toBehavior = toBehavior; pressed = new RiseEdgeTrigger(); } // No change needed public Behavior getToBehavior() { return(this.toBehavior); } }
Here is the software for the RiseEdgeTrigger.java class:
package com.qualcomm.ftcrobotcontroller.geekmybot; /** * Created by David Lempia on 1/17/2016. */public class RiseEdgeTrigger { private boolean z1=false; private boolean out=false; public boolean calculate(boolean in){ if (in & !this.z1) this.out=true; else this.out=false; this.z1=in; return(this.out); } }
For full copies of this software, see: https://github.com/dlacres/GeekMyBot.git
If you use this behavior framework, I ask that you share the love. Print out a copy of the GeekMyBot logo and put it on your robot along with the http://geekmybot.blogspot.com/ URL address. Share this Blog with your friends.
If you develop an event that you are particularly proud of, I ask that you add a comment to this article and share your behavior along with a link to your software.
