title: TextView and setText from class
body: <p>I know there's a couple of questions about this out there but I still don't get it. 
  I have an activity </p>
  
  <pre><code>package test.example.om;
  
  import android.app.Activity;
  import android.os.Bundle;
  import android.widget.TextView;
  import test.example.om.Texter;
  
  public class TextActivity extends Activity {
     /** Called when the activity is first created. */
  
      public String text="Helloo";
      @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         Texter myTexter = new Texter(); 
         myTexter.textTexter();
  
  
     }
      public void textSet(){
          TextView tv = (TextView) findViewById(R.id.myTextViewInXml);
             tv.setText(text);
  }
  }
  </code></pre>
  
  <p>And a class Texter </p>
  
  <pre><code>package test.example.om;
  
  import android.widget.TextView;
  import android.app.Activity;
  import android.os.Bundle;
  import android.widget.TextView;
  
  public class Texter extends Activity{
  String string="Helloo";
  
  
  public void textTexter(){
      TextView tv = (TextView) findViewById(R.id.myTextViewInXml);
         tv.setText(string);
  }
  }
  </code></pre>
  
  <p>The LogCat is showing a NullPointerException and the app crashes. What am I doing wrong and how can I setText to the TextView from another class than the main activity class?</p>