导入方法

Now we will look at the methods used for importing data into a component. These methods are invoked for the drop gesture, or the paste action, when the component is the target of the operation. The TransferHandler methods for importing data are:

• canImport(TransferHandler.TransferSupport)—This method is called repeatedly during a drag gesture and returns true if the area below the cursor can accept the transfer, or false if the transfer will be rejected. For example, if a user drags a color over a component that accepts only text, the canImport method for that component's TransferHandler should return false.

• importData(TransferHandler.TransferSupport)—This method is called on a successful drop (or paste) and initiates the transfer of data to the target component. This method returns true if the import was successful and false otherwise.

You will notice that these import methods take a TransferHandler.TransferSupport argument. Next we look at the TransferSupport class and then some sample import methods.