Module com.googlecode.lanterna
Package com.googlecode.lanterna.gui2

Class Panel

  • All Implemented Interfaces:
    Component, Container, TextGUIElement
    Direct Known Subclasses:
    SplitPanel
    public class Panel
extends AbstractComponent<Panel>
implements Container
    This class is the basic building block for creating user interfaces, being the standard implementation of Container that supports multiple children. A Panel is a component that can contain one or more other components, including nested panels. The panel itself doesn't have any particular appearance and isn't interactable by itself, although you can set a border for the panel and interactable components inside the panel will receive input focus as expected.

    • Field Detail

      • components

        private final java.util.List<Component> components

      • cachedPreferredSize

        private TerminalSize cachedPreferredSize

      • fillColorOverride

        private TextColor fillColorOverride

    • Constructor Detail

      • Panel

        public Panel()
        Default constructor, creates a new panel with no child components and by default set to a vertical LinearLayout layout manager.

    • Method Detail

      • addComponent

        public Panel addComponent​(Component component)
        Adds a new child component to the panel. Where within the panel the child will be displayed is up to the layout manager assigned to this panel. If the component has already been added to another panel, it will first be removed from that panel before added to this one.
        Parameters:
        component - Child component to add to this panel
        Returns:
        Itself

      • addComponent

        public Panel addComponent​(int index,
                          Component component)
        Adds a new child component to the panel. Where within the panel the child will be displayed is up to the layout manager assigned to this panel. If the component has already been added to another panel, it will first be removed from that panel before added to this one.
        Parameters:
        component - Child component to add to this panel
        index - At what index to add the component among the existing components
        Returns:
        Itself

      • addComponent

        public Panel addComponent​(Component component,
                          LayoutData layoutData)
        This method is a shortcut for calling: 
             
     component.setLayoutData(layoutData);
     panel.addComponent(component);
        Parameters:
        component - Component to add to the panel
        layoutData - Layout data to assign to the component
        Returns:
        Itself

      • containsComponent

        public boolean containsComponent​(Component component)
        Description copied from interface: Container
        Returns true if this container contains the supplied component either directly or indirectly through intermediate containers.
        Specified by:
        containsComponent in interface Container
        Parameters:
        component - Component to check if it's part of this container
        Returns:
        true if the component is inside this Container, otherwise false

      • removeComponent

        public boolean removeComponent​(Component component)
        Description copied from interface: Container
        Removes the component from the container. This should remove the component from the Container's internal data structure as well as call the onRemoved(..) method on the component itself if it was found inside the container.
        Specified by:
        removeComponent in interface Container
        Parameters:
        component - Component to remove from the Container
        Returns:
        true if the component existed inside the container and was removed, false otherwise

      • removeAllComponents

        public Panel removeAllComponents()
        Removes all child components from this panel
        Returns:
        Itself

      • setLayoutManager

        public Panel setLayoutManager​(LayoutManager layoutManager)
        Assigns a new layout manager to this panel, replacing the previous layout manager assigned. Please note that if the panel is not empty at the time you assign a new layout manager, the existing components might not show up where you expect them and their layout data property might need to be re-assigned.
        Parameters:
        layoutManager - New layout manager this panel should be using
        Returns:
        Itself

      • getFillColorOverride

        public TextColor getFillColorOverride()
        Returns the color used to override the default background color from the theme, if set. Otherwise null is returned and whatever theme is assigned will be used to derive the fill color.
        Returns:
        The color, if any, used to fill the panel's unused space instead of the theme's color

      • setFillColorOverride

        public void setFillColorOverride​(TextColor fillColor)
        Sets an override color to be used instead of the theme's color for Panels when drawing unused space. If called with null, it will reset back to the theme's color.
        Parameters:
        fillColor - Color to draw the unused space with instead of what the theme definition says, no null to go back to the theme definition

      • getLayoutManager

        public LayoutManager getLayoutManager()
        Returns the layout manager assigned to this panel
        Returns:
        Layout manager assigned to this panel

      • getChildCount

        public int getChildCount()
        Description copied from interface: Container
        Returns the number of children this container currently has
        Specified by:
        getChildCount in interface Container
        Returns:
        Number of children currently in this container

      • getChildren

        public java.util.Collection<Component> getChildren()
        Description copied from interface: Container
        Returns collection that is to be considered a copy of the list of children contained inside of this object. Modifying this collection will not affect any internal state.

        This method isn't deprecated but it should have originally been defined as returning a List instead of a Collection. See getChildrenList for a method with this signature.

        Specified by:
        getChildren in interface Container
        Returns:
        Child-components inside of this Container
        See Also:
        Container.getChildrenList()

      • getChildrenList

        public java.util.List<Component> getChildrenList()
        Description copied from interface: Container
        Returns list that is to be considered a copy of the list of children inside of this container. Modifying this list will not affect any internal state. This method is essentially the same as getChildren but the returned collection is a list.
        Specified by:
        getChildrenList in interface Container
        Returns:
        Child-components inside of this Container
        See Also:
        Container.getChildren()

      • createDefaultRenderer

        protected ComponentRenderer<Panel> createDefaultRenderer()
        Description copied from class: AbstractComponent
        When you create a custom component, you need to implement this method and return a Renderer which is responsible for taking care of sizing the component, rendering it and choosing where to place the cursor (if Interactable). This value is intended to be overridden by custom themes.
        Specified by:
        createDefaultRenderer in class AbstractComponent<Panel>
        Returns:
        Renderer to use when sizing and drawing this component

      • calculatePreferredSize

        public TerminalSize calculatePreferredSize()
        Description copied from class: AbstractComponent
        Invokes the component renderer's size calculation logic and returns the result. This value represents the preferred size and isn't necessarily what it will eventually be assigned later on.
        Overrides:
        calculatePreferredSize in class AbstractComponent<Panel>
        Returns:
        Size that the component renderer believes the component should be

      • isInvalid

        public boolean isInvalid()
        Description copied from interface: TextGUIElement
        Checks if this element (or any of its child components, if any) has signaled that what it's currently displaying is out of date and needs re-drawing.
        Specified by:
        isInvalid in interface TextGUIElement
        Overrides:
        isInvalid in class AbstractComponent<Panel>
        Returns:
        true if the component is invalid and needs redrawing, false otherwise

      • nextFocus

        public Interactable nextFocus​(Interactable fromThis)
        Description copied from interface: Container
        Given an interactable, find the next one in line to receive focus. If the interactable isn't inside this container, this method should return null.
        Specified by:
        nextFocus in interface Container
        Parameters:
        fromThis - Component from which to get the next interactable, or if null, pick the first available interactable
        Returns:
        The next interactable component, or null if there are no more interactables in the list

      • previousFocus

        public Interactable previousFocus​(Interactable fromThis)
        Description copied from interface: Container
        Given an interactable, find the previous one in line to receive focus. If the interactable isn't inside this container, this method should return null.
        Specified by:
        previousFocus in interface Container
        Parameters:
        fromThis - Component from which to get the previous interactable, or if null, pick the last interactable in the list
        Returns:
        The previous interactable component, or null if there are no more interactables in the list

      • handleInput

        public boolean handleInput​(KeyStroke key)
        Description copied from interface: Container
        If an interactable component inside this container received a keyboard event that wasn't handled, the GUI system will recursively send the event to each parent container to give each of them a chance to consume the event. Return false if the implementer doesn't care about this particular keystroke and it will be automatically sent up the hierarchy the to next container. If you return true, the event will stop here and won't be reported as unhandled.
        Specified by:
        handleInput in interface Container
        Parameters:
        key - Keystroke that was ignored by the interactable inside this container
        Returns:
        true if this event was handled by this container and shouldn't be processed anymore, false if the container didn't take any action on the event and want to pass it on

      • updateLookupMap

        public void updateLookupMap​(InteractableLookupMap interactableLookupMap)
        Description copied from interface: Container
        Takes a lookup map and updates it with information about where all the interactables inside of this container are located.
        Specified by:
        updateLookupMap in interface Container
        Parameters:
        interactableLookupMap - Interactable map to update

      • invalidate

        public void invalidate()
        Description copied from interface: Component
        Marks the component as invalid and requiring to be re-drawn at next opportunity. Container components should take this as a hint to layout the child components again.
        Specified by:
        invalidate in interface Component
        Overrides:
        invalidate in class AbstractComponent<Panel>