title: cannot go to next interface (android)
body: <p>I'm trying to include some e-mail features in my program. I've created a menu interface for some e-mail features also. So, I have a main menu, and when I click on the e-mail button, I get to the e-mail menu. However, after I click one of the e-mail menu buttons (inbox and send new) program crashes. I've been searching on the internet and have done other menus by using the same implementation method. However, I cannot figure out why I'm getting this error... I'd really appreciate some help, my codes are below:</p>
  
  <p>MainActivity.java where I click on the e-mail button and go to the e-mail menu (Nothing is wrong here, I think):</p>
  
  <pre><code>mail_Button = (ImageButton)findViewById(R.id.mailButton);
          mail_Button.setOnClickListener(new View.OnClickListener()
          {
              @Override
              public void onClick(View arg0) 
              {
                  // TODO Auto-generated method stub
                  Intent myIntent = new Intent(MainActivity.this, Mail.class);
                  //myIntent.putExtra("key", value);
                  MainActivity.this.startActivity(myIntent);
              }
  
          });
  </code></pre>
  
  <p>My mail activity_mail.xml file, where I have two buttons for inbox and send new e-mail:</p>
  
  <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent" &gt;
  
      &lt;Button
          android:id="@+id/inbox"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignParentTop="true"
          android:layout_centerHorizontal="true"
          android:layout_marginTop="139dp"
          android:text="@string/mail_inbox_button" /&gt;
  
      &lt;Button
          android:id="@+id/send_new"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_below="@+id/button1"
          android:layout_centerHorizontal="true"
          android:layout_marginTop="61dp"
          android:text="@string/mail_sendnew_button" /&gt;
  
      &lt;TextView
          android:id="@+id/textView1"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignParentTop="true"
          android:layout_centerHorizontal="true"
          android:layout_marginTop="25dp"
          android:text="@string/mail_main_message"
          android:textAppearance="?android:attr/textAppearanceLarge" /&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>My Inbox.java file where I will do some stuff after I get rid of this problem with your help :)</p>
  
  <pre><code>public class Inbox extends Activity {
       protected void onCreate(Bundle savedInstanceState) {
              super.onCreate(savedInstanceState);
              setContentView(R.layout.activity_mail_inbox);
          }
  
  }
  </code></pre>
  
  <p>My activity_mail_inbox.xml file where I want to put some stuff(currently empty):</p>
  
  <pre><code>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      android:orientation="vertical" &gt;
  
  &lt;/LinearLayout&gt; 
  </code></pre>
  
  <p>My SendNew.java file whicj I'm going to use when I'm going to send e-mail:</p>
  
  <pre><code>public class SendNew extends Activity {
       protected void onCreate(Bundle savedInstanceState) {
              super.onCreate(savedInstanceState);
              setContentView(R.layout.activity_mail_send);
          }
  
  }
  </code></pre>
  
  <p>My activity_mail_send.xml file where I have fields for user to fill and a send button</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;ScrollView
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/ScrollView01"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:scrollbars="vertical"&gt;
      &lt;LinearLayout
          android:layout_width="fill_parent"
          android:orientation="vertical"
          android:layout_height="fill_parent"&gt;
  
          &lt;TextView
              android:id="@+id/TextViewTitle"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="@string/feedbacktitle"
              android:textSize="10pt"&gt;&lt;/TextView&gt;
  
  
          &lt;EditText
              android:id="@+id/EditTextName"
              android:layout_height="wrap_content"
              android:hint="@string/feedbackname"
              android:inputType="textPersonName"
              android:layout_width="fill_parent"&gt;&lt;/EditText&gt;
  
          &lt;EditText
              android:id="@+id/EditTextEmail"
              android:layout_height="wrap_content"
              android:hint="@string/feedbackemail"
              android:inputType="textEmailAddress"
              android:layout_width="fill_parent"&gt;&lt;/EditText&gt;
  
          &lt;EditText
              android:id="@+id/EditTextFeedbackBody"
              android:layout_height="wrap_content"
              android:hint="@string/feedbackbody"
              android:inputType="textMultiLine"
              android:lines="5"
              android:layout_width="fill_parent"&gt;&lt;/EditText&gt;
  
          &lt;Button
              android:id="@+id/ButtonSendFeedback"
              android:layout_width="match_parent"
              android:layout_height="62dp"
              android:onClick="sendFeedback"
              android:text="@string/feedbackbutton" &gt;
  &lt;/Button&gt;
  
      &lt;/LinearLayout&gt;
  &lt;/ScrollView&gt;
  </code></pre>
  
  <p>So, I cannot reach the two xml files when I click on the buttons and I can't figure out why.</p>