java - Prevent scrollbars disappearing when exiting component inside the JScrollPane -

i made jpanel contains jscrollpane surrounds jtextarea. want hide scrollbars when mouse exits jscrollpane.

if set mouselistener on jscrollpane, nothing happens. if set on jtextarea scrollbars hide/unhide correctly, cannot click them because outside bounds of jtextarea.\

how can prevent scrollbars disappearing when try click them?

code example 1. hiding , unhiding + changing transparency works.

problem: cannot click scrollbars, disappear because exit jtextarea.

public class transparenttextarea extends jtextarea {  private static final color light_transparent = new color(0, 0, 0, 150); private static final color heavy_transparent = new color(0, 0, 0, 50);  public transparenttextarea(final gamemodel model) {     setopaque(false);     setforeground(color.white);     setbackground(heavy_transparent);     seteditable(false);     addmouselistener(new mouselistener() {          @override         public void mousereleased(mouseevent e) {             // todo auto-generated method stub          }          @override         public void mousepressed(mouseevent e) {             // todo auto-generated method stub          }          @override         public void mouseexited(mouseevent e) {             model.setlogactive(false);             setbackground(heavy_transparent);         }          @override         public void mouseentered(mouseevent e) {             model.setlogactive(true);             setbackground(light_transparent);         }          @override         public void mouseclicked(mouseevent e) {             // todo auto-generated method stub          }     }); } }  public class logger extends jscrollpane implements panelobserver,     changelistener {  private gamemodel model;  public logger(final gamemodel model) {     super(new transparenttextarea(model));     this.model = model;     setopaque(false);     getviewport().setopaque(false);     setborder(borderfactory.createemptyborder());     setviewportborder(borderfactory.createemptyborder());     model.addpanelobserver(this);     model.addchangelistener(this); }  @override public void panelresized() {     float x = model.getpanelwidth() * 0.01f;     float y = model.getpanelheight() * 0.70f;     float width = model.getpanelwidth() * 0.30f;     float height = model.getpanelheight() * 0.28f;      setbounds((int) x, (int) y, (int) width, (int) height); }  @override public void statechanged(changeevent e) {     if (model.islogactive()) {         setverticalscrollbarpolicy(jscrollpane.vertical_scrollbar_as_needed);         sethorizontalscrollbarpolicy(jscrollpane.horizontal_scrollbar_as_needed);     } else {         setverticalscrollbarpolicy(jscrollpane.vertical_scrollbar_never);         sethorizontalscrollbarpolicy(jscrollpane.horizontal_scrollbar_never);     } } } 

code example 2.

problem tried fix creating panel around , using mouseexited, not work since childs consume it.

public class logger extends jpanel implements panelobserver, mouselistener {  private static final color light_transparent = new color(0, 0, 0, 150); private static final color heavy_transparent = new color(0, 0, 0, 50);  private gamemodel model; private jtextarea textarea; private jscrollpane scrollpane;  public logger(gamemodel model) {     super(null);      this.model = model;     setopaque(false);      textarea = new jtextarea();     textarea.setopaque(false);     textarea.setforeground(color.white);     textarea.setbackground(heavy_transparent);     textarea.seteditable(false);      scrollpane = new jscrollpane(textarea);     scrollpane.setopaque(false);     scrollpane.getviewport().setopaque(false);     scrollpane.setborder(borderfactory.createemptyborder());     scrollpane.setviewportborder(borderfactory.createemptyborder());     add(scrollpane);      model.addpanelobserver(this);     addmouselistener(this); }  @override public void panelresized() {     float x = model.getpanelwidth() * 0.01f;     float y = model.getpanelheight() * 0.70f;     float width = model.getpanelwidth() * 0.30f;     float height = model.getpanelheight() * 0.28f;      setbounds((int) x, (int) y, (int) width, (int) height);     scrollpane.setbounds(0, 0, (int) width, (int) height); }  @override public void mouseclicked(mouseevent e) {}  @override public void mousepressed(mouseevent e) {}   @override public void mousereleased(mouseevent e) {}  @override public void mouseentered(mouseevent e) {     scrollpane.setverticalscrollbarpolicy(jscrollpane.vertical_scrollbar_as_needed);     scrollpane.sethorizontalscrollbarpolicy(jscrollpane.horizontal_scrollbar_as_needed);     textarea.setbackground(light_transparent); }  @override public void mouseexited(mouseevent e) {         scrollpane.setverticalscrollbarpolicy(jscrollpane.vertical_scrollbar_never);         scrollpane.sethorizontalscrollbarpolicy(jscrollpane.horizontal_scrollbar_never);         textarea.setbackground(heavy_transparent); } } 

just tried , works fine:

 textarea.addmousemotionlistener(new mousemotionadapter() {                 @override                 public void mousemoved(mouseevent arg0) {                     scrollpane.setverticalscrollbarpolicy(jscrollpane.vertical_scrollbar_as_needed);                     scrollpane.sethorizontalscrollbarpolicy(jscrollpane.horizontal_scrollbar_as_needed);                 }             });   scrollpane.addmouselistener(new mouseadapter() {              @override             public void mouseexited(mouseevent e) {                  scrollpane.setverticalscrollbarpolicy(jscrollpane.vertical_scrollbar_never);                 scrollpane.sethorizontalscrollbarpolicy(jscrollpane.horizontal_scrollbar_never);             }         }); 

the idea long mouse moving within textarea, scrollbar visible , works fine. moves outside scrollpane it's not visible anymore.