DisplayMessageActivity cannot be resolved to a type-Building first android App
<p>Hi I have just began working on the first android application on <strong>developer.android.com</strong>.</p>

<p>well to start with I got to learn many error origins and their solutions from S.O. , but i have been trying to figure out this statement 
<em>"DisplayMessageActivity cannot be resolved to a type"</em> while we have to set an Intent for button onclick function. It shows this error in the line where the code line is:</p>

<pre><code>Intent intent = new Intent (this, DisplayMessageActivity.class);
</code></pre>

<p>here is the java file:</p>

<p><strong>MainActivity.java</strong></p>

<pre><code>}
/**called when the user clicks the send button*/
public void sendMessage(View view) {
    Intent intent = new Intent (this, DisplayMessageActivity.class);
    EditText editText = (EditText) findViewById (R.id.edit_message);
    String message = editText.getText().toString();
    intent.putExtra(EXTRA_MESSAGE, message);
    startActivity (intent);
}
}
</code></pre>

<p>I tried a lot find which class do I need to import now, and searched but no avail.
may be I am a beginner is what I miss here.</p>
