Interface Interactable

All Superinterfaces:
Component, TextGUIElement
All Known Implementing Classes:
AbstractInteractableComponent, AbstractListBox, ActionListBox, Button, CheckBox, CheckBoxList, ComboBox, ImageComponent, Menu, MenuItem, RadioBoxList, Table, TextBox
public interface Interactable extends Component
This interface marks a component as able to receive keyboard input from the user. Components that do not implement this interface in some way will not be able to receive input focus. Normally if you create a new component, you'll probably want to extend from AbstractInteractableComponent instead of implementing this one directly.
See Also:

  • Method Details

    • getCursorLocation

      TerminalPosition getCursorLocation()
      Returns, in local coordinates, where to put the cursor on the screen when this component has focus. If null, the cursor should be hidden. If you component is 5x1 and you want to have the cursor in the middle (when in focus), return [2,0]. The GUI system will convert the position to global coordinates.
      Returns:
      Coordinates of where to place the cursor when this component has focus

    • handleInput

      Interactable.Result handleInput(KeyStroke keyStroke)
      Accepts a KeyStroke as input and processes this as a user input. Depending on what the component does with this key-stroke, there are several results passed back to the GUI system that will decide what to do next. If the event was not handled or ignored, Result.UNHANDLED should be returned. This will tell the GUI system that the key stroke was not understood by this component and may be dealt with in another way. If event was processed properly, it should return Result.HANDLED, which will make the GUI system stop processing this particular key-stroke. Furthermore, if the component understood the key-stroke and would like to move focus to a different component, there are the Result.MOVE_FOCUS_* values. This method should be invoking the input filter, if it is set, to see if the input should be processed or not.

      Notice that most of the built-in components in Lanterna extends from AbstractInteractableComponent which has a final implementation of this method. The method to override to handle input in that case is AbstractInteractableComponent.handleKeyStroke(KeyStroke).

      Parameters:
      keyStroke - What input was entered by the user
      Returns:
      Result of processing the key-stroke

    • takeFocus

      Interactable takeFocus()
      Moves focus in the BasePane to this component. If the component has not been added to a BasePane (i.e. a Window most of the time), does nothing. If the component has been disabled through a call to setEnabled(boolean), this call also does nothing.
      Returns:
      Itself

    • onEnterFocus

      void onEnterFocus(Interactable.FocusChangeDirection direction, Interactable previouslyInFocus)
      Method called when this component gained keyboard focus.
      Parameters:
      direction - What direction did the focus come from
      previouslyInFocus - Which component had focus previously (null if none)

    • onLeaveFocus

      void onLeaveFocus(Interactable.FocusChangeDirection direction, Interactable nextInFocus)
      Method called when keyboard focus moves away from this component
      Parameters:
      direction - What direction is focus going in
      nextInFocus - Which component is receiving focus next (or null if none)

    • isFocused

      boolean isFocused()
      Returns true if this component currently has input focus in its root container.
      Returns:
      true if the interactable has input focus, false otherwise

    • setInputFilter

      Interactable setInputFilter(InputFilter inputFilter)
      Assigns an input filter to the interactable component. This will intercept any user input and decide if the input should be passed on to the component or not. null means there is no filter.
      Parameters:
      inputFilter - Input filter to assign to the interactable
      Returns:
      Itself

    • getInputFilter

      InputFilter getInputFilter()
      Returns the input filter currently assigned to the interactable component. This will intercept any user input and decide if the input should be passed on to the component or not. null means there is no filter.
      Returns:
      Input filter currently assigned to the interactable component

    • setEnabled

      Interactable setEnabled(boolean enabled)
      Prevents the component from receiving input focus if this is called with a false value. The component will then behave as a mainly non-interactable component. Input focus can be re-enabled by calling this with true. If the component already has input focus when calling this method, it will release focus and no component is focused until there is user action or code that chooses a new focus.
      Parameters:
      enabled - If called with false, this interactable won't receive input focus until it's called again with true.
      Returns:
      Itself

    • isEnabled

      boolean isEnabled()
      Returns true if this component is able to receive input as a regular interactable component. This will return false if input focus has been disabled through calling setEnabled(boolean).
      Returns:
      true if this component can receive input focus, false otherwise

    • isFocusable

      boolean isFocusable()
      Returns true if this interactable component is currently able to receive input focus. This is similar but different from isEnabled(), which tells lanterna that the entire component is disabled when it is returning false, compared to this method which simply claims that the component is currently not ready to handle input. The AbstractInteractableComponent implementation always return true here but for example the list box components will override and return false here if they are empty. Note that you can still programmatically force input focus onto the component, returning false here won't prevent that.
      Returns:
      true if this component wants to receive input focus, false otherwise.