Question

So I have 2 XML layout files.
One is the menu and the other is the app.
So, now I have some buttons on the one XML file and some other buttons on the other file.

So this code works:

    setContentView(R.layout.main);
    start = (Button) findViewById(R.id.button1);

    start.setOnClickListener(this);

But if I change the view and write this:

    setContentView(R.layout.random);
    add_person = (Button) findViewById(R.id.add);

    add_person.setOnClickListener(this); //crash here

The app crashes!

Answer 1

add_person is null so get Nullpointer Exception and you have Button in random.xml which has add as id?

if not then add

<Button android:id="@+id/add" ... />