java.lang.NullPointerException: Attempt to invoke virtual method android

Question

i am a beginner in the android, and i dont know what is the problem in my code ! and i need your help, this is my code: i am trying to do a calculator = - / * ..... and i re

Answer 1

Either check you have initialized the view or may be layout not has been attached to activity.

    password = (EditText) findViewById(R.id.password);

or

setContentView(R.layour.login_screen);