title: Android findViewById() in Custom View
body: <p>I've written my custom View and i want to update some other views after interacting with my custom view.</p>
  
  <p><strong>Main Layout:</strong></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  
  &lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:custom="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:layout_height="match_parent"&gt;
  
      &lt;EditText
          android:id="@+id/display_name"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:inputType="text"
          android:layout_centerHorizontal="true"
          android:tag="name"
          android:ems="10" /&gt;
  
      &lt;EditText
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:inputType="number"
          android:ems="10"
          android:id="@+id/id_number"
          android:layout_centerHorizontal="true"
          android:layout_below="@id/display_name"/&gt;
  
      &lt;ge.altasoft.custom_views.IdNumber
          android:id="@+id/custom_id_number"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_centerHorizontal="true"
          android:layout_below="@id/id_number"
          android:paddingLeft="35dip"
          custom:firstName="@id/display_name"/&gt;
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p><strong>Custom View Layout:</strong></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  
  &lt;RelativeLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"&gt;
  
      &lt;EditText
          android:id="@+id/id_number_custom"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:inputType="number"
          android:ems="10"
          android:paddingRight="35dip" /&gt;
  
      &lt;ImageButton
          android:id="@+id/load_data_button"
          android:layout_width="30dip"
          android:layout_height="30dip"
          android:layout_centerVertical="true"
          android:src="@drawable/load_data"
          android:layout_toRightOf="@id/id_number_custom" /&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p><strong>Custom View Class, constructor and listener:</strong></p>
  
  <pre><code> private int firstNameViewID;
  
  public IdNumber (Context context, AttributeSet attrs) {
          super(context, attrs);
          initViews();
  
          TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.IdNumber);
          final int N = a.getIndexCount();
          for(int i = 0; i &lt; N; i++){
              int attr = a.getIndex(i);
              switch(attr){
                  case R.styleable.IdNumber_firstName:
                      firstNameViewID = a.getResourceId(attr, -1);
                      break;
              }
          }
          a.recycle();
      }
  
  
  
   private void initViews() {
          inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
          inflater.inflate(R.layout.id_number_edit_text_custom, this, true);
          editText = (EditText) findViewById(R.id.id_number_custom);
          loadButton = (ImageButton) findViewById(R.id.load_data_button);
          loadButton.setVisibility(RelativeLayout.INVISIBLE);
          loadData();
      }
  
  private void loadData(){
          loadButton.setOnClickListener(new OnClickListener() {
              @Override
              public void onClick(View v) {
                  EditText firstName = (EditText) findViewById(R.id.display_name);
                  firstName.setText("Some Text");
              }
          });
      }
  </code></pre>
  
  <p>The Problem is that  <code>EditText firstName = (EditText) findViewById(R.id.display_name);</code> returns null. 
  I know that just calling <code>findViewById()</code> will search the view in the layout that i inflated it. </p>
  
  <p>If it's possible, how can I get the view of EditText with id: display_name from the main layout ?</p>
  
  <p>Thanks in Advance.</p>