```
Button btnEditor;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    btnEditor = (Button) findViewById(R.id.btnEditor);

    //some code

    btnEditor.setOnClickListener(new View.OnClickListener(){
        public void onClick(View arg0) {

        }
    });
}

```

`btnEditor.setOnClickListener(new View.OnClickListener()` gives me a **Null Pointer Exception**.
btnEditor is earlier connecter to XML Button by:
`btnEditor = (Button) findViewById(R.id.btnEditor);`

In my main.xml file:

```
<Button
        android:id="@+id/btnEditor"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginTop="16dp"
        android:text="Editor"
        android:textSize="48dp"
        android:textStyle="bold"
        android:typeface="normal" android:layout_gravity="bottom"/>

```

Seriously, I have no idea what to do...

**RESOLVED**

I forgot that I had two `main.xml` files:

* /res/layout
* /res/layout-large

One of them (in large dir) didn't contain a Button inside, so I got an error while running application on device using large layout.