title: get main activity context for imageView
body: <p>I'm using thread (runOnUiThread) for adding imageView to mainActivity.<br/>
  i don't know what should i import to constructor! It want context and i tried <code>MainActivity.this</code> and <code>getApplicationContext()</code> and <code>getBaseContext()</code> but it doesn't work!</p>
  
  <pre><code>public void addImageView(final int belowId,final int id){
      runOnUiThread(new Runnable() {
          @Override
          public void run() {
              RelativeLayout rSub= (RelativeLayout) findViewById(R.id.rSub);
              RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
                      RelativeLayout.LayoutParams.WRAP_CONTENT,
                      RelativeLayout.LayoutParams.WRAP_CONTENT);
              lp.addRule(RelativeLayout.BELOW, belowId);
              lp.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
              ImageView iv = new ImageView(?????);
              iv.setImageResource(R.drawable.ic_launcher);
              iv.setId(id);
              rSub.addView(iv, lp);   
          }
      });
  }
  </code></pre>
  
  <p>and call it :</p>
  
  <pre><code>new Thread(new Runnable() {
      @Override
      public void run() {
          addImageView(belowId, tempId);
       }
  }).start();
  </code></pre>
  
  <p>any help appreciated!</p>