java - Calling Graphics function from another functionJava -

i trying button call graphics function in java take lives left , draw appropriate parts hang man game. working except drawing. believe because of way calling function i'm not sure. thanks

code button:

if(temptext == label.gettext()){            lives--;            panel2.paintcomponent();            if (lives == 0){                joptionpane.showmessagedialog(null,"you lose");                buttona.setenabled(false);                buttonb.setenabled(false);                buttonc.setenabled(false);                buttond.setenabled(false);                buttone.setenabled(false);                buttonf.setenabled(false);                buttong.setenabled(false);                buttonh.setenabled(false);                buttoni.setenabled(false);                buttonj.setenabled(false);                buttonk.setenabled(false);                buttonl.setenabled(false);                buttonm.setenabled(false);                buttonn.setenabled(false);                buttono.setenabled(false);                buttonp.setenabled(false);                buttonq.setenabled(false);                buttonr.setenabled(false);                buttons.setenabled(false);                buttont.setenabled(false);                buttonu.setenabled(false);                buttonv.setenabled(false);                buttonw.setenabled(false);                buttonx.setenabled(false);                buttony.setenabled(false);                buttonz.setenabled(false);             }        } 

code drawing

class colorpanel extends jpanel { final hangman man = new hangman(); graphics g; public void paintcomponent(){    super.paintcomponent(g);    this.setbackground(color.white);    if(man.lives == 5){        g.drawoval(175, 100, 50, 50);     }    if(man.lives == 4){        g.drawline(200, 200, 200, 150);    }    if(man.lives == 3){        g.drawline(200, 200, 250, 250);    }    if(man.lives == 2){        g.drawline(200, 200, 150, 250);    }    if(man.lives == 1){        g.drawline(150, 150, 200, 175);    }    if(man.lives == 0){        g.drawline(250, 150, 200, 175);    }    g.drawline(100, 300, 100, 50);    g.drawline(200, 50, 100, 50);    g.drawline(200, 100, 200, 50);    g.drawoval(50, 300, 100, 50); } } 

errors

at colorpanel.paintcomponent(hangman.java:2573)

at hangman$3.actionperformed(hangman.java:445)

you should never call paintcomponent or super.paintcomponent directly, , should not using appears null graphics object. i'm frankly surprised you're not getting nullpointerexception code. , in fact, maybe -- never show enough of exception's stacktrace know type of error getting (suggestion -- show entire exception stacktrace).

instead have button press change state of drawnig jpanek, change 1 of key fields, , call repaint() on drawing jpanel. inside of drawing jpanel's protected void paintcomponent(graphics g) method, call super method, , use field states decide draw.

for instance, field simple int gets incremented or decremented every time wrong letter picked, , paintcomponent uses int decide , how many body parts draw.

check out tutorial, lesson: performing custom painting see details of how want draw in gui.

i want second eddyg's recommendation -- use array of jbutton or hashmap<character, jbutton> organize gui code better. way create jbuttons in simple loop, looping int (char c =a; c <= 'z'; c++) {...}. make code more compact, easier understand , easier debug.

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for example,

import java.awt.borderlayout; import java.awt.gridlayout; import java.awt.event.actionevent; import java.awt.event.actionlistener; import java.beans.propertychangeevent; import java.beans.propertychangelistener; import java.util.hashmap; import java.util.map;  import javax.swing.*;  @suppresswarnings("serial") public class letterselectiongrid extends jpanel {    public static final string selected_letter = "selected letter";    private map<character, abstractbutton> buttonmap = new hashmap<>();     public letterselectiongrid() {       setborder(borderfactory.createtitledborder("select letters"));       buttonlistener buttonlistener = new buttonlistener();       setlayout(new gridlayout(3, 0));       (char c = 'a'; c <= 'z'; c++) {          string text = string.valueof(c);          jbutton button = new jbutton(text);          button.addactionlistener(buttonlistener);          add(button); // add gui          buttonmap.put(c, button);       }    }     private class buttonlistener implements actionlistener {       @override       public void actionperformed(actionevent e) {          abstractbutton btn = (abstractbutton) e.getsource();          char selectedchar = e.getactioncommand().charat(0);            btn.setenabled(false);          firepropertychange(selected_letter, null, selectedchar);       }    }     public void setallenabled(boolean enabled) {       (abstractbutton btn : buttonmap.values()) {          btn.setenabled(enabled);       }    }     private static void createandshowgui() {       final letterselectiongrid letterselectiongrid = new letterselectiongrid();        jbutton resetbutton = new jbutton(new abstractaction("reset") {           @override          public void actionperformed(actionevent e) {             letterselectiongrid.setallenabled(true);          }       });       jpanel southpanel = new jpanel();       southpanel.add(resetbutton);        letterselectiongrid.addpropertychangelistener(letterselectiongrid.selected_letter, new propertychangelistener() {           @override          public void propertychange(propertychangeevent evt) {             system.out.println("selected letter is: " + evt.getnewvalue());          }       });        jframe frame = new jframe("buttongrid");       frame.setdefaultcloseoperation(jframe.exit_on_close);       frame.getcontentpane().add(letterselectiongrid);       frame.getcontentpane().add(southpanel, borderlayout.page_end);       frame.pack();       frame.setlocationrelativeto(null);       frame.setvisible(true);    }     public static void main(string[] args) {       swingutilities.invokelater(new runnable() {          public void run() {             createandshowgui();          }       });    } }