如何将数组中的某些 File 元素复制到新的 File 数组？

Question

This is it possible to implement this? I have File foo[] that has a list of 5 files. But I only want to copy foo[0] and foo[3] into File bar[] so that bar[] will only have 2 elements.

My code gets the length of foo[], then if the index of the selected file equals the index for i, add foo[i] to bar[i]. This is the possible code I've constructed:

for(int i = 0; i < foo.length; i++){

    if(list_fileListing.getSelectedIndex() == i){
        bar[i] = foo[i];
    }
}

* list_fileListing.getSelectedIndex() holds the list of selected files from the JList.* The reason being is that I have a list of files that are selectable in a JList. And from that list, I want the user to be able to select which files to attach to an email.

Answer 1

if you call getSelectedValues() on your JList, you will get an array containing all items currently selected:

Object[] selectedObjects = list_fileListing.getSelectedValues();

for (int i = 0; i < selectedObjects.length; i++)
{
    File aFile = (File)selectedObjects[i];

    // attach this file
}

is this sufficient?

Answer 2

It looks like you're using Java7 since you have JList.getSelectedValues() deprecated. Try using getSelectedValuesList() method instead. If you need an array you can use list.getSelectedValuesList().toArray()

Answer 3

According to your comments, your JList contains String instances and not File instances. So you could do something like

List<String> selectedFilesAsStrings = list_fileListing.getSelectedValuesAsList();
//selectedFilesAsStrings will never be null, but can be empty
List<File> selectedFiles = new ArrayList<File>( selectedFilesAsStrings.size() );
for( String fileName : selectedFilesAsStrings ){
  selectedFiles.add( new File( fileName ) );
}
File[] bar = selectedFiles.toArray( new File[ selectedFiles.size() ] );

which will set the bar array pointing to an array containing the selected File instances