JScrollPane and JList auto scroll

Question

I\'ve got the next code:

    listModel = new DefaultListModel();
    listModel.addElement(dateFormat.format(new Date()) + \": Msg1\");
    messageList = new          


        

Answer 1

@question enquirer. Please change your code from

messageScrollList.getVerticalScrollBar().addAdjustmentListener(new AdjustmentListener() {  
    public void adjustmentValueChanged(AdjustmentEvent e) {  
        e.getAdjustable().setValue(e.getAdjustable().getMaximum());  
    }
});

to

messageScrollList.getVerticalScrollBar().addAdjustmentListener(new AdjustmentListener() {  
    public void adjustmentValueChanged(AdjustmentEvent e) {  
        e.getAdjustable().setValue(e.getAdjustable().getValue());
    }
}); 

That is change getMaximum() to getValue() Then it works as required. getMaximum() takes the scroller to its maximum; while getValue() takes it wherever event happens.

You can avoid using this piece of code altogether if you put one line

messageScrollList.setViewportView(messageList);

That works like add(component) for jList and gets its inherent behaviour.