Search code examples
javalistviewjavafxjavafx-8mouseclick-event

Mimicking CTRL+Click Multiple Selection in ListView using Javafx


I'm trying to find different ways of selecting multiple items in a ListView. The GUI will be running on a touch screen monitor, So I won't be able to CTRL+Click. From researching through various past posts, I have been able to implement Multiple Selection via keeping all the selected items in an Array and then looping through it to get the final selections. The only problem I have with my code is that compared to a CTRL +click , the selection is done smoothly, where as my code leads to a type flickering every time a new item is selected. So basically the listView clears all the selections and then selects the correct ones. Is there a way to make this transition go smoothly? Would it be easier to mimic a touch to have CTRL+click effect?

selectedList = new int[totalTypes];//total number of item properties

for(int x=0; x<selectedList.length;x++){//0 = not selected, 1 = selected
    selectedList[x]=0;
}
testView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);

    testView.setOnMouseClicked(new EventHandler<Event>(){
        @Override
        public void handle(Event event){
                if(selectedList[testView.getSelectionModel().getSelectedIndex()]==0){
                    selectedList[testView.getSelectionModel().getSelectedIndex()]=1;
                }
                else{
                    selectedList[testView.getSelectionModel().getSelectedIndex()]=0;
                }

                for(int x=0; x<selectedList.length;x++){
                    if(selectedList[x]==1){
                        testView.getSelectionModel().select(x); 
                    }
                    else{
                        testView.getSelectionModel().clearSelection(x);;
                    }
                }


        }

    });

Solution

  • You could handle changing the selection when a user clicks a ListCell yourself instead of using the standard event handling:

    @Override
    public void start(Stage primaryStage) {
        ListView<Integer> listView = new ListView<>();
        listView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
        listView.getItems().setAll(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
        listView.addEventFilter(MouseEvent.MOUSE_PRESSED, evt -> {
            Node node = evt.getPickResult().getIntersectedNode();
    
            // go up from the target node until a list cell is found or it's clear
            // it was not a cell that was clicked
            while (node != null && node != listView && !(node instanceof ListCell)) {
                node = node.getParent();
            }
    
            // if is part of a cell or the cell,
            // handle event instead of using standard handling
            if (node instanceof ListCell) {
                // prevent further handling
                evt.consume();
    
                ListCell cell = (ListCell) node;
                ListView lv = cell.getListView();
    
                // focus the listview
                lv.requestFocus();
    
                if (!cell.isEmpty()) {
                    // handle selection for non-empty cells
                    int index = cell.getIndex();
                    if (cell.isSelected()) {
                        lv.getSelectionModel().clearSelection(index);
                    } else {
                        lv.getSelectionModel().select(index);
                    }
                }
            }
        });
    
        Scene scene = new Scene(listView);
    
        primaryStage.setScene(scene);
        primaryStage.show();
    }