Package tripleplay.ui

Class HistoryGroup<T,W extends Element<?>>

java.lang.Object

tripleplay.ui.Element<T>

tripleplay.ui.Container<T>

tripleplay.ui.Composite<HistoryGroup<T,W>>

tripleplay.ui.HistoryGroup<T,W>

Type Parameters:

T - The type of item backing this history

W - The type of element or widget stored in this history

All Implemented Interfaces:

Iterable<Element<?>>

Direct Known Subclasses:

HistoryGroup.Labels

public abstract class HistoryGroup<T,W extends Element<?>>
extends Composite<HistoryGroup<T,W>>

A scrolling vertical display, optimized for showing potentially very long lists such as a chat log. Supports:

• addition of new elements on the end
• pruning old elements from the beginning
• progressive rendering of newly visible items in the list
• automatically keeping the last item visible
• purging of old rendered elements that are no longer visible

Items are stored in a backing array. Each entry in the array may or may not have a corresponding Element visible (presuming that the rendering and storage of elements is expensive). When the user scrolls, entries are rendered on demand using render(tripleplay.ui.HistoryGroup.Entry). Entries that are not visible use an estimated size for layout purposes. This of course may produce some artifacts during scrolling, which is the penalty of not computing the exact size.

NOTE: The elements in the UI (type W) must not be mutated after rendering and must have a constant size given a particular item and width. See render(tripleplay.ui.HistoryGroup.Entry).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	HistoryGroup.Labels	History group of just labels.
static class	HistoryGroup.RenderableLabel	A label that exposes the width hint and preferred size.

Nested classes/interfaces inherited from class tripleplay.ui.Container

Container.Mutable<T extends Container.Mutable<T>>

Nested classes/interfaces inherited from class tripleplay.ui.Element

Element.Take

Field Summary

Fields inherited from class tripleplay.ui.Element

layer

Method Summary

Modifier and Type	Method	Description
void	addItem(T item)	Adds a new item to the end of the history.
boolean	atBottom()	Tests if the history is currently at the bottom.
void	pruneOld(int adjustment)	Prunes the given number of entries from the beginning of the history.
void	scrollToBottom()	Issues a request to scroll to the bottom of the list of history elements.
void	setVerticalGap(int vgap)	Sets the vertical gap between history elements.

Methods inherited from class tripleplay.ui.Composite

childAt, childCount, iterator, setStylesheet, stylesheet

Methods inherited from class tripleplay.ui.Container

removeFromParent

Methods inherited from class tripleplay.ui.Element

addStyles, addStyles, bindEnabled, bindVisible, bounds, constraint, enabledSlot, hierarchyChanged, isAdded, isEnabled, isShowing, isVisible, location, parent, setConstraint, setEnabled, setStyles, setStyles, setVisible, size, styles, visibleSlot, x, y

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Method Details

atBottom

public boolean atBottom()

Tests if the history is currently at the bottom. If the history is at the bottom, then subsequent additions will cause automatic scrolling. By default, new groups are at the bottom. Subsequent upward scrolling will clear this and scrolling to the bottom will set it again.

scrollToBottom

public void scrollToBottom()

Issues a request to scroll to the bottom of the list of history elements.

pruneOld

public void pruneOld(int adjustment)

Prunes the given number of entries from the beginning of the history.

addItem

public void addItem(T item)

Adds a new item to the end of the history. If the history is at the bottom, the item will be rendered immediately, otherwise the message group is invalidated so that the scroll bounds will be updated.

setVerticalGap

public void setVerticalGap(int vgap)

Sets the vertical gap between history elements. By default, the gap is set to 1.