The findViewById will return a non-null Widget object, only if you first called setContentView and inflated the layout that contains it. That is why nextButton works and backButton is null - giving you your NullPointerException.
For a simple application, an easier way to create 2 pages, would be to create 2 activities and switch between them. http://developer.android.com/reference/android/app/Activity.html Btw, there is related interesting read at http://android-developers.blogspot.com/2009/02/faster-screen-orientation-change.html Balwinder Kaur Open Source Development Center ·T· · ·Mobile· stick together The views, opinions and statements in this email are those of the author solely in their individual capacity, and do not necessarily represent those of T-Mobile USA, Inc. On Jul 22, 2:27 am, elegos <[email protected]> wrote: > Hello there! > > I'm a newbie in Android programming, and was exploring the possibility > to switch between more than - one - layouts (i.e. more pages?). > > So I've created a new XML layout page (called second.xml) and created > some things in there. At least I've created a button to switch back to > the first layout, but a NullPointerException fires up when the > application starts, and that only for the "back" button, while the > "next" button just works great. > > Any suggestion? > Thanks :) > > package com.elegos.test; > > import android.app.Activity; > import android.os.Bundle; > import android.view.View; > import android.view.View.OnClickListener; > import android.widget.Button; > import android.widget.TextView; > > public class ListViewTest extends Activity { > /** Called when the activity is first created. */ > @Override > public void onCreate(Bundle savedInstanceState) { > super.onCreate(savedInstanceState); > setContentView(R.layout.main); > > TextView myText = (TextView)findViewById(R.id.myTextView); > > Button nextButton = (Button)findViewById(R.id.ButtonNext); > Button backButton = (Button)findViewById(R.id.ButtonBack); > > nextButton.setOnClickListener(getCListener(R.layout.second)); > try {backButton.setOnClickListener(getCListener > (R.layout.main));} catch(Exception e) {myText.append("\n"+e.toString > ());} > } > > final private OnClickListener getCListener(final int layout) { > return new Button.OnClickListener() { > public void onClick(View v) { > setContentView(layout); > } > }; > } > > } > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Beginners" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-beginners?hl=en -~----------~----~----~----~------~----~------~--~---
