ChristopherLowe

Well I have had a frustrating few hours working out how to add buttons dynamically. Here is how I did it. Firstly, you need to give the layout an ID in the xml file.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/buttonlayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >   
</LinearLayout>

Note the id: buttonlayout. Now you need to access the layout in onCreate and create some layout parameters.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
 
    Button myButton = new Button(this);
    myButton.setText("Push Me");
 
    LinearLayout ll = (LinearLayout)findViewById(R.id.buttonlayout);
    LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
    ll.addView(myButton, lp);
 
}

The reason I was having such a crappy time with this is because I foolishly placed setContentView(R.layout.main) at the bottom. You are not able to access the ID of a view with findViewById(R.id.buttonlayout) until you have set the content view. I was getting a null pointer exception which causes a Force close.