android - TextWatcher caused crash -

here's newbie android developing.

while i'm making app calculate calories burnt exercise, found adding textwatcher edittext cause crashing add on "etenergy".

i've searched many questions crashed, of them making infinity loop in listener , solved remove listener add later. added doesn't work.

i found message in logcat when can't find log made in method:

warning activitymanager(744): activity pause timeout activityrecord{41ea1128 u0 [package name]/.mainactivity t65 f}

the following problem codes in mainactivity.java. without them can execute correctly need them complete app.

protected edittext etenergy,etweight,ettime; protected textview tvcals; //double t,a; //don't make sense in following code. mytextwatch tw;  class mytextwatch implements textwatcher{      @override     public void beforetextchanged(charsequence s, int start, int count, int after) {      }      @override     public void ontextchanged(charsequence s, int start, int before, int count) {         etenergy.removetextchangedlistener(this);         etweight.removetextchangedlistener(this);         ettime.removetextchangedlistener(this);         log.d("textwatcher","textchangedlistenerremoved");         etenergy.addtextchangedlistener(this);         etweight.addtextchangedlistener(this);         ettime.addtextchangedlistener(this);      }      @override     public void aftertextchanged(editable s) {      } }//end of class mytextwatch  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);     etenergy=(edittext) findviewbyid(r.id.etenergy);     etweight=(edittext) findviewbyid(r.id.etweight);     ettime=(edittext) findviewbyid(r.id.ettime);     etenergy.addtextchangedlistener(tw);     etweight.addtextchangedlistener(tw);     ettime.addtextchangedlistener(tw);     tvcals=(textview) findviewbyid(r.id.tvcals); } 

almost forgot i'm using android studio 1.1.0 , app run on physical device htc butterfly android version 4.4.2 , minimum api level of app 14(icecreamsandwich/4.0).

english not native language i'll try hard read reply.

thanks reading. appreciates answering!

it seems edittext's null. please make sure in activity_main layout have edittext's following ids: etenergy, etweight, ettime

and side note - you're not creating new object of mytextwatch , trying pass null in addtextchangedlistener(tw).