Question

I am trying to use relative layout in my app. With two TextViews and a Button. Here’s the xml file:

    <RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:padding="30dip"
android:orientation="vertical">


<TextView
    android:id="@+id/up"
    android:text="@string/start_game"
    android:layout_height="wrap_content"
    android:layout_width="wrap_content"
    />

 <TextView
    android:id="@+id/level"
    android:layout_height="wrap_content"
    android:layout_width="wrap_content"
     android:layout_below="@id/up"/>
    />

   <Button android:id="@+id/start"
   android:text = "@string/go"
   android:layout_height="wrap_content" 
   android:layout_width="fill_parent"  
   android:layout_alignParentBottom="true"
  />

  </RelativeLayout>

Now, the TextView with id=up shows perfectly. For the second TextView (with id=level) i want to add text to it via my java code. Here’s what i did:

       TextView text = (TextView) findViewById(R.id.level);
       text.setText("Hello Android");

But this crashes the program. What is my mistake here?

Answer 1

So that’s it… you must always call setContentView before using findViewById.