Libraries.Robots.Lego.Button Documentation
The Button class is an object representation of the LEGO Mindstorms EV3 button section located below the screen on the brick. It includes functionality for the buttons as well as the LED that surrounds them. The buttons and LED patterns available are represented as class constants.
Example Code
use Libraries.Robots.Lego.Button
use Libraries.Robots.Lego.Motor
class Main
action Main
Button button
Motor motor
motor:SetSpeed("A", 720) //two motors to move the robot
motor:SetSpeed("B", 720)
repeat while true
button:WaitForButtonPress()
if button:IsButtonPressed(button:UP_BUTTON)
motor:RotateForward("A")
motor:RotateForward("B")
button:SetLightPattern(button:SOLID_GREEN_LIGHT)
elseif button:IsButtonPressed(button:DOWN_BUTTON)
motor:RotateBackward("A")
motor:RotateBackward("B")
button:SetLightPattern(button:FLASHING_RED_LIGHT)
else
motor:Stop("A")
motor:Stop("B")
button:SetLightPattern(button:NO_LIGHT)
end
end
end
end
Inherits from: Libraries.Language.Object
Summary
Variable Summary Table
Variables | Description |
---|---|
integer PULSING_GREEN_LIGHT | |
text RIGHT_BUTTON | |
text UP_BUTTON | |
text ESCAPE_BUTTON | |
integer SOLID_RED_LIGHT | |
integer SOLID_ORANGE_LIGHT | |
integer FLASHING_GREEN_LIGHT | |
text DOWN_BUTTON | |
integer NO_LIGHT | |
integer PULSING_ORANGE_LIGHT | This action is used to find out if a certain button is currently being pressed. |
integer SOLID_GREEN_LIGHT | |
integer PULSING_RED_LIGHT | |
text CENTER_BUTTON | |
integer FLASHING_ORANGE_LIGHT | |
integer FLASHING_RED_LIGHT | |
text LEFT_BUTTON |
Actions Summary Table
Actions | Description |
---|---|
Compare(Libraries.Language.Object object) | This action compares two object hash codes and returns an integer. |
Equals(Libraries.Language.Object object) | This action determines if two objects are equal based on their hash code values. |
GetHashCode() | This action gets the hash code for an object. |
IsButtonPressed(text button) | This action is used to find out if a certain button is currently being pressed. |
SetLightPattern(integer pattern) | This action displays a light pattern on the LED surrounding the EV3's buttons. |
WaitForButtonPress() | This action halts the current program execution until a button is pressed on the EV3 brick. |
Actions Documentation
Compare(Libraries.Language.Object object)
This action compares two object hash codes and returns an integer. The result is larger if this hash code is larger than the object passed as a parameter, smaller, or equal. In this case, -1 means smaller, 0 means equal, and 1 means larger. This action was changed in Quorum 7 to return an integer, instead of a CompareResult object, because the previous implementation was causing efficiency issues.
Example Code
Object o
Object t
integer result = o:Compare(t) //1 (larger), 0 (equal), or -1 (smaller)
Parameters
- Libraries.Language.Object: The object to compare to.
Return
integer: The Compare result, Smaller, Equal, or Larger.
Equals(Libraries.Language.Object object)
This action determines if two objects are equal based on their hash code values.
Example Code
use Libraries.Language.Object
use Libraries.Language.Types.Text
Object o
Text t
boolean result = o:Equals(t)
Parameters
- Libraries.Language.Object: The to be compared.
Return
boolean: True if the hash codes are equal and false if they are not equal.
GetHashCode()
This action gets the hash code for an object.
Example Code
Object o
integer hash = o:GetHashCode()
Return
integer: The integer hash code of the object.
IsButtonPressed(text button)
This action is used to find out if a certain button is currently being pressed.
Example Code
use Libraries.Robots.Lego.Button
use Libraries.Robots.Lego.Sound
Button button
Sound sound
repeat until button:IsButtonPressed(button:ESCAPE_BUTTON)
if button:IsButtonPressed(button:LEFT_BUTTON)
sound:PlayTone(1000, 20)
elseif button:IsButtonPressed(button:RIGHT_BUTTON)
sound:PlayTone(2000, 20)
end
end
Parameters
- text button: is used to specify the button to be checked. The Button class has text constants that can be used for this parameter.
Return
boolean: a boolean value denoting whether the button specified in the parameter is being pressed in or not.
SetLightPattern(integer pattern)
This action displays a light pattern on the LED surrounding the EV3's buttons.
Example Code
use Libraries.Robots.Lego.Button
use Libraries.Robots.Lego.Utility
Button button
Utility utility
button:SetLightPattern(button:SOLID_GREEN_LIGHT)
utility:DelayMilliseconds(2000)
button:SetLightPattern(button:FLASHING_RED_LIGHT)
utility:DelayMilliseconds(2000)
button:SetLightPattern(button:PULSING_ORANGE_LIGHT)
utility:DelayMilliseconds(2000)
Parameters
- integer pattern: specifies the light pattern to be displayed on the EV3's brick. The Button class has integer constants that can be used for this parameter.
WaitForButtonPress()
This action halts the current program execution until a button is pressed on the EV3 brick.
Example Code
use Libraries.Robots.Lego.Button
use Libraries.Robots.Lego.Motor
Button button
Motor motor
motor:SetSpeed("B", 1080)
motor:RotateForward("B")
button:WaitForButtonPress()
motor:Stop("B")