Error At Android STUDIO -

i'm learning program android on android studio . when start application, following message appears on avd " unfortunalety , guitarstorev2 has stopped ."

can me ? (sorry if stupid mistake , not have familiarity language , , excuse error portuguese , because brazilian , not speak english fluently )

grateful attention mark tonial

public class mainactivity extends appcompatactivity {  button btn_iniciaapp;  public void inicia () {     button btn_inciaapp = (button) findviewbyid(r.id.btn_iniciaapp); }  // iniciando tela de produtos public void iniciaprod() {      intent activityprod = new intent(this, activityprod.class);     startactivity(activityprod); }  // evento ao clicar no botão public void inicialistener() {     this.btn_iniciaapp.setonclicklistener(new onclicklistener() {         public void onclick(view arg0) {             mainactivity.this.iniciaprod();         }     }); }  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     this.setcontentview(r.layout.activity_main);     this.inicia();     this.inicialistener(); } 

}

button btn_iniciaapp;  public void inicia () {     button btn_inciaapp = (button) findviewbyid(r.id.btn_iniciaapp); } 

your program crashing nullpointerexception. here, inicia isn't setting value of class's btn_iniciaapp: it's creating locally scoped button shadowing class's btn_iniciaapp. you're setting value of local button, not class's.

since class's btn_iniciaapp never set, remains null, , call this.btn_iniciaapp.setonclicklistener trigger nullpointerexception.