I'm having trouble adding a button to a layout that I've created in XML. Here's what I want to achieve: //some class else { startActivity(new Intent(StatisticsScreen.this, ScreenTemperature.class)); } //// //ScreenTemperatureClass @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //this is where I call another class that //displays a nice graph setContentView(new GraphTemperature(getApplicationContext())); } I want to add a Button to this new screen so that it'll appear below the graph. I've tried creating a LinearLayout view, then create a Button and add it to this view but I just get NullPointerExceptions.. Any help would be appreciated. Thanks EDIT#1 Here's what I've tried using that created a NullPointerException and 'force close': Button buybutton; LinearLayout layout; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(new GraphTemperature(getApplicationContext())); layout = (LinearLayout) findViewById(R.id.statsviewlayout); Button buyButton = new Button(this); buyButton.setText(R.string.button_back); buyButton.setLayoutParams(new LayoutParams( ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT)); layout.addView(buyButton); } And here's the logcat error: ERROR/AndroidRuntime(293): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.weatherapp/com.weatherapp.ScreenTemperature}: java.lang.NullPointerException ERROR/AndroidRuntime(293): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663) ERROR/AndroidRuntime(293): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) ERROR/AndroidRuntime(293): at android.app.ActivityThread.access$2300(ActivityThread.java:125) ERROR/AndroidRuntime(293): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) theres abviously more lines to do with this error in logcat, not sure if you want it? EDIT#2 So i tried bhups method: @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); GraphTemperature GT = new GraphTemperature(getApplicationContext()); layout = (LinearLayout) findViewById(R.id.statsviewlayout); Button buyButton = new Button(this); buyButton.setText(R.string.button_back); buyButton.setLayoutParams(new LayoutParams( ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT)); layout.addView(GT); // line 27 layout.addView(buyButton); setContentView(layout); } This method produced the same logcat error as above, NullPointerException, indicating it was something to do with line no. 27 which is the layout.addView line of code. Any ideas? Thanks again