Re: Drag and drop for non-String objects

Nigel Wade <>
Mon, 21 Jul 2008 15:28:20 +0100
Hendrik Maryns wrote:

Hash: SHA1

Hi all,

I???d like to revive a thread I started a while ago but which got no
satisfying answers.

I want to implement drag and drop for non-String objects.

Setting: a JList with a DefaultListModel. It contains Formula???s (a
class of my own making, with a whole hierarchy underneath it:
Conjunction, Negation etc.). I then do

result.setTransferHandler(new FormulaTransferHandler());

on the JList. Here follows an almost minimal SSCCE, note that it needs
Java 6:

Here you specify that the DataFlavor which drop will accept is of class

~ this.localFormulaFlavor = new ActivationDataFlavor(Formula.class,
~ DataFlavor.javaJVMLocalObjectMimeType, "Arrays of formulas");
~ }

~ /**
~ * The data flavor for formulas local to the JVM.
~ */
~ private final DataFlavor localFormulaFlavor;

~ /**
~ * The formulas being transfered.
~ */
~ private Object[] transferedFormulas = null;

~ @Override
~ protected Transferable createTransferable(final JComponent c) {
~ final JList formulaList = (JList) c;
~ this.transferedFormulas = formulaList.getSelectedValues();
~ return new DataHandler(this.transferedFormulas, this.localFormulaFlavor
~ .getMimeType());
~ // TODO: add support via serialization?
~ }

...but what you actually transfer is an Object[]

Nigel Wade

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