Java Programing For Android App Wont Load -

ive been making android app using android develepor kit , created layout medium text , 1 button

it meant show text in dialog when click buttom when run app on device test it freezes , doesnt show button or text added whole device freezes.

i cant figure out ive dont wrong im complete noob @ im hoping can me figure out.

public class mainactivity extends activity implements onclicklistener {      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          button button1 = (button)findviewbyid(android.r.id.button1);         button1.setonclicklistener(this);     }       @override     public void onclick(view v) {         dialog d = new dialog(this);         d.settitle("success!");         textview tv = new textview(this);         tv.settext("some text here.");         d.setcontentview(tv);         d.show();     }  } 

if there in logcat, helpful. believe problem here

 button button1 = (button)findviewbyid(android.r.id.button1); 

assuming have button in activity_main.xml androidid="@+id/button1", line should be

button button1 = (button)findviewbyid(r.id.button1); 

when use namespace android.r.somereference telling pre-defined android resource. here resource 1 have declared leave off android.