I get a forcestop occasionally when I press buttons other than the first
<p>I have 3 buttons in total. And it seemed that, if I don't press the first button, and instead second or third button right after I startup, my application will forcestop.</p>

<p>My code for part1 : <a href="http://pastebin.com/udkEdF3E" rel="nofollow">http://pastebin.com/udkEdF3E</a></p>

<pre><code>package project.ernest;

 import android.app.Activity;
 import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

 public class Part1 extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);


      final Button a = (Button) findViewById(R.id.Disclaimer); 
      a.setOnClickListener(new View.OnClickListener() {
          public void onClick(View view) { 
            Intent b = new Intent(getBaseContext(), Part2.class);         
            Part1.this.startActivity(b); 


      final Button c = (Button) findViewById(R.id.Orientation); 
      c.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) { 
            Intent d = new Intent(getBaseContext(), Part3.class);         
            Part1.this.startActivity(d);


      final Button e = (Button) findViewById(R.id.Course); 
      e.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) { 
            Intent f = new Intent(getBaseContext(), Part4.class);         
            Part1.this.startActivity(f);
        }
      });
      };
        });
      };
            });
      };
    }
</code></pre>

<p>my code for main.xml : <a href="http://pastebin.com/SxfxfJ4a" rel="nofollow">http://pastebin.com/SxfxfJ4a</a></p>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@color/myColor" android:weightSum="1"&gt;
    &lt;LinearLayout android:orientation="vertical" android:id="@+id/linearLayout1" android:weightSum="1" android:layout_width="wrap_content" android:layout_height="404dp"&gt;
        &lt;TextView android:text="@string/HospName" android:id="@+id/textView1" android:textSize="20mm" android:layout_width="324dp" android:layout_height="142dp"&gt;&lt;/TextView&gt;
        &lt;Button android:text="@string/Disclaimer" android:layout_weight="0.37" android:textSize="5mm" android:layout_height="75dp" android:layout_width="fill_parent" android:id="@+id/Disclaimer" android:drawingCacheQuality="high" android:onClick="@string/DisclaimerHandler"&gt;&lt;/Button&gt;
        &lt;Button android:text="@string/Orientation" android:textSize="5mm" android:layout_height="75dp" android:layout_weight="0.37" android:layout_width="fill_parent" android:id="@+id/Orientation" android:onClick="@string/OrientationHandler"&gt;&lt;/Button&gt;
        &lt;Button android:text="@string/Course" android:textSize="5mm" android:layout_height="75dp" android:layout_weight="0.37" android:layout_width="fill_parent" android:id="@+id/Course" android:onClick="@string/CourseHandler"&gt;&lt;/Button&gt;
    &lt;/LinearLayout&gt;
    &lt;LinearLayout android:layout_width="match_parent" android:orientation="horizontal" android:layout_weight="0.19" android:layout_height="wrap_content" android:id="@+id/linearLayout2" android:weightSum="1"&gt;
        &lt;Button android:layout_weight="0.23" android:text="@string/Search" android:textSize="1.9mm" android:layout_height="75dp" android:layout_width="75dp" android:onClick="@string/SearchHandler" android:id="@+id/Search"&gt;&lt;/Button&gt;
        &lt;Button android:layout_weight="0.23" android:text="@string/Contact" android:textSize="1.9mm" android:layout_height="75dp" android:layout_width="75dp" android:onClick="@string/ContactHandler" android:id="@+id/Contact"&gt;&lt;/Button&gt;
        &lt;Button android:onClick="@string/LinkHandler" android:layout_height="75dp" android:layout_width="75dp" android:layout_weight="0.23" android:textSize="1.9mm" android:text="@string/Link" android:id="@+id/Link"&gt;&lt;/Button&gt;
        &lt;Button android:layout_weight="0.23" android:text="@string/Copyright" android:textSize="1.9mm" android:layout_height="75dp" android:layout_width="75dp" android:onClick="@string/CopyrightHandler" android:id="@+id/Copyright"&gt;&lt;/Button&gt;
    &lt;/LinearLayout&gt;
&lt;/LinearLayout&gt;
</code></pre>

<p>The error I get is either:</p>

<pre><code>java.lang.IllegalStateException: Could not find a method CourseHandler(View) in activity class project.ernest.Part1 or...
java.lang.IllegalStateException: Could not find a method OrientationHandler(View) in activity class project.ernest.Part1 or...
</code></pre>

<p>Please help me out!</p>
