jMonkeyEngine-wiki/docs/modules/contributions/pages/gui/tonegodgui/dragelement.adoc

= dragelement
:revnumber: 2.0
:revdate: 2020/07/27



== DragElement Class

Contrary to hearsay, the DragElement is <strong>NOT</strong> a male Element dressed in women's clothing.  It simply provides an easy-to-use Element pre-configured for managing Drag & Drop interaction, with a few extra features.

The DragElement class uses the single constructor of the Element class and configures the Element to:

[source,java]
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Element.setIsDragDropDragElement(true);
Element.setIsMovable(true);

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It also provides a way of managing multiple drop elements and reacting to the appropriately.


=== Enable/Disable the DragElement

[source,java]
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dragEl.setIsEnabled(boolean isEnabled);
dragEl.getIsEnabled();

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=== Managing Drop Elements

[source,java]
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// Add an element as a valid drop Element
dragEl.addDropElement(Element element);

// Retrieve an element(s)
dragEl.getDropElements(); // Return all drop elements
dragEl.getDropElement(int index); // Returns a single drop element by index

// Remove drop elements
dragEl.removeDropElement(int index);
dragEl.removeDropElement(Element element);

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=== Responding to Incorrect Drops

[source,java]
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// Enable/disable springback (returns drag element to original position)
dragEl.setUseSpringBack(boolean useSpringBack);
dragEl.getUseSpringBack();

// Use SlideTo effect when springback is called
dragEl.setUseSpringBackEffect(boolean useSpringBackEffect);
dragEl.getUseSpringBackEffect();

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=== Responding to Correct Drops

[source,java]
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//Position the DragElement in the center of drop element
dragEl.setUseLockToDropElementCenter(boolean lockToDropElementCenter);
dragEl.getUseLockToDropElementCenter();

// Use SlideTo effect when centering
dragEl.setUseLockToDropElementEffect(boolean useLockToDropElementEffect);
dragEl.getUseLockToDropElementEffect();

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=== Abstract Event Methods

[source,java]
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public abstract void onDragStart(MouseButtonEvent evt);
public abstract void onDragEnd(MouseButtonEvent evt, int index, Element dropElement);

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