title: How to get current content view of activity?
body: <p>I have a content view say primary set on main activity, when clicked on a button, it sets another content view say secondary with setContentView(R.layout.sec_content). What i want now that when Back Button Pressed, It should set the primary content if current view is secondary otherwise it should close the activity. how do i do that?
  here is my code</p>
  
  <pre><code>public class Ch_1 extends AppCompatActivity {
  
  Button men1, men2, men3;
  TextView tv1;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_ch_1);
  
      men1 = (Button)findViewById(R.id.men1);
      men1.setOnClickListener(new View.OnClickListener() {
  
          @Override
          public void onClick(View arg0) {
              // TODO Auto-generated method stub
              setContentView(R.layout.activity_read__view);
              TextView tv1 = (TextView)findViewById(R.id.read_view);
              tv1.setText("This is text in READ_VIEW activity");
  
  
  
  
          }
      });
  
  
  }
  </code></pre>
  
  <p>}</p>