Spec-Zone .ru
спецификации, руководства, описания, API
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The
TransferSupport
class, one of the inner classes of the TransferHandler
class introduced in JDK 6, serves two functions. As the name suggests, its first function is to support the transfer process and for that purpose it provides several utility methods used to access the details of the data transfer. The following list shows the methods that can be used to obtain information from the TransferHandler
. Several of these methods are related to drop actions, which will be discussed in
Component getComponent()
— This method returns the target component of the transfer.int getDropAction()
COPY
, MOVE
or LINK
) when the transfer is a drop. If the transfer is not a drop, this method throws an exception.int getUserDropAction()
ACTION_LINK
action. For more information on user drop actions, see the API for
DropTargetDragEvent
int getSourceDropActions()
DataFlavor[] getDataFlavors()
boolean isDataFlavorSupported(DataFlavor)
DataFlavor
is supported. The
DataFlavor
imageFlavor
), a string (stringFlavor
), a list of files (javaFileListFlavor
), and so on.Transferable getTransferable()
Transferable
data for this transfer. It is more efficient to use one of these methods to query information about the transfer than to fetch the transferable and query it, so this method is not recommended unless you cannot get the information another way.DropLocation getDropLocation()
JList
component returns the index in the list where the drop occurred. If the transfer is not a drop, this method throws an exception.Now that you are familiar with the TransferSupport
utility methods, let us look at sample canImport
and importData
methods:
public boolean canImport(TransferSupport supp) { // Check for String flavor if (!supp.isDataFlavorSupported(stringFlavor)) { return false; } // Fetch the drop location DropLocation loc = supp.getDropLocation(); // Return whether we accept the location return shouldAcceptDropLocation(loc); } public boolean importData(TransferSupport supp) { if (!canImport(sup)) { return false; } // Fetch the Transferable and its data Transferable t = supp.getTransferable(); String data = t.getTransferData(stringFlavor); // Fetch the drop location DropLocation loc = supp.getDropLocation(); // Insert the data at this location insertAt(loc, data); return true; }
Next we look at how you can set the drop mode for selected components.