java - object oriented programming in android -
i want use method in 1 of classes in class , code doesn't have error when run project "unfortunately project * hast stopped" error. , when copy method instead of creating object , on run program without problem , can 1 tell me may problem ? public void onclick(view arg0) { string p = "+989357835774"; string m = "test"; sendsms sms = new sendsms(); sms.sms(p, m); } public class sendsms extends activity { public void sms (string phonno , string message){ pendingintent pi = pendingintent.getactivity(this, 0, new intent(this, sendsms.class), 0); smsmanager sms = smsmanager.getdefault(); sms.sendtextmessage(phonno, "+9891100500", message , pi, null); } } these errors : 08-23 19:31:00.065: e/androidruntime(9985): fatal exception: main 08-23 19:31:00.065: e/androidruntime(9985): java.lang.nullpointerexception 08-23 19:31:00.065: e/androidruntime(9985): ...