java - How to hide elements with in a JComboBox? -

say have jcombobox contains elements in vector...

 public class shade(){        //code creating panels etc , other components/containers        jcheckbox primary = new jcheckbox("primary", false);                   vector<string> colours = new vector<string>(); } public shade(){ //settitle, look&feel, defaultcloseoperation, layouts etc etc...   colours.add(0, "purple);  colours.add(1, "red");  colours.add(2, "blue");  colours.add(3, "magenta");  jcombobox<string> colourselector = new jcombobox<string>(colours);  } 

if jcheckbox primary selected want 'hide' colours purple , magneta jcombobox, once primary jcheckbox has been deselected reveal hidden elements, original list pertains.

i tried doing this...

   public class eventhandler implements itemlistener(){     shade refobj; public eventhandler(shade rinsefm){ refobj = rinsefm; }  #overriding abstract implemented method... public void itemstatechanged(itemevent event){  if(refobj.primary.isselected() == true){ refobj.colours.hide(// index of colours required hide)) } } } 

the hide method doesn't exist, there analogous this.

try this:

private jframe frame = new jframe("jcomboexample"); private jcheckbox primary = new jcheckbox("primary"); private jcombobox<string> colorselector;  private string[] colorstohide = { "purple", "magenta" };  public jcomboexample() {     swingutilities.invokelater(() -> {         setupframe();         setupcheckbox();         initjcombobox("purple", "red", "blue", "magenta");         frame.add(primary, borderlayout.north);         frame.add(colorselector, borderlayout.center);     }); }  private void setupframe() {     frame.setsize(300, 100);     frame.setlocationbyplatform(true);     frame.setdefaultcloseoperation(3);     frame.setlayout(new borderlayout()); }  private void setupcheckbox() {     primary.addactionlistener(event -> {         if(primary.isselected()) {             for(string color: colorstohide) {                 colorselector.removeitem(color);             }          } else {             for(string color: colorstohide) {                 colorselector.additem(color);             }         }     }); }  private void initjcombobox(string... colors) {     colorselector = new jcombobox<string>(colors); }  public void setvisbility(boolean visibility) {     frame.setvisible(visibility); }  public static void main(string[] args) {     jcomboexample example = new jcomboexample();     example.setvisbility(true); } 

this class implements callback(adds actionlistener) when checkbox clicked. in callback, when checkbox activated, remove colors in array colorstohide. if checkbox not activated, add them back.

side notes:

in java, should not using vector purpose. vectors largely considered obsolete. see post: why java vector class considered obsolete or deprecated?

you should create gui / handle gui state changes on edt. swing not thread-safe , although in cases may appear un-needed, practice call swingutilities.invokelater or swingutilities.invokeandwait before handling gui.