(Java Android) Keep EditText Values after switching layouts

I have an application with 2 layouts which are using the same Activity-Class. In the second layout are some EditTexts, but when type in something and I switch back to the Main-Layout and from there back to the second-layout, the value of the EditTexts are gone.

I switch the layouts using setContentView(R.layout.[layoutname]);

How can I switch the layouts without using the values?