제가 Slide Button을 구현 하려고

http://www.androidpub.com/?document_srl=878847

그냥가자님의 게시물을 보고 따라했습니다.

그런데 XML에서 런타임 에러가 나네요 ㅠㅠ

에러 나는 부분 로그 캡쳐 해서 첨부파일로 올렸습니다..

코드는 아래와 같구요

slide_button.xml

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content">
 <a.b.c.SlideButton
  android:layout_width="112px"
  android:layout_height="48px"
  android:content="@+id/slideContentLayout"
  android:handle="@+id/slideHandle"
  android:orientation="horizontal"
  android:id="@+id/slideButton"
  android:background="@drawable/btnback">
  <Button
   android:id="@+id/slideBtn"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:background="@drawable/btn"/>
  <LinearLayout
   android:id="@+id/slideContentLayout"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:layout_weight="1"
   android:background="#000000">
 </LinearLayout>
 </a.b.c.SlideButton>
</LinearLayout>

 package com.slidingtest;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.Checkable;
import android.widget.SlidingDrawer;
import android.widget.SlidingDrawer.OnDrawerCloseListener;
import android.widget.SlidingDrawer.OnDrawerOpenListener;

public class SlideButton extends SlidingDrawer implements Checkable, OnDrawerOpenListener, OnDrawerCloseListener {
 int mButtonResource = 0; 
 OnCheckChangedListner mOnCheckChangedListner; 
 
 public SlideButton(Context context, AttributeSet attrs) {
  super(context, attrs);
  // TODO Auto-generated constructor stub
  setOnDrawerOpenListener(this);
  setOnDrawerCloseListener(this);
 }
 
 @Override
 public boolean isChecked() {
  // TODO Auto-generated method stub
  return !isOpened();
 }
 
 @Override
 public void setChecked(boolean checked) {
  // TODO Auto-generated method stub
  if(!isOpened() != checked){
   if(checked) {
    this.animateClose();
   }
   else {
    this.animateOpen();
   }
  }
 }
 
 @Override
 public void toggle() {
  // TODO Auto-generated method stub
  // super.toggle();
  if(!isOpened()) {
   this.animateOpen();
  }
  else {
   this.animateClose();
  }
 }
 
 public interface OnCheckChangedListner {
  public void onCheckChanged(View v, boolean isChecked);
 }

 @Override
 public void onDrawerOpened() {
  // TODO Auto-generated method stub
  if(mOnCheckChangedListner != null) {
   mOnCheckChangedListner.onCheckChanged(this, isChecked());
  }
 }
 
 @Override
 public void onDrawerClosed() {
  // TODO Auto-generated method stub
  if(mOnCheckChangedListner != null) {
   mOnCheckChangedListner.onCheckChanged(this, isChecked());
  }
 }
 
 public OnCheckChangedListner getOnCheckChangedListner() {
  return mOnCheckChangedListner;
 }
 
 public void setOnCheckChangedListener(OnCheckChangedListner onCheckChangedListner) {
  this.mOnCheckChangedListner = onCheckChangedListner;
 }
}

 package com.slidingtest;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
 
 private SlideButton sb;
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.slide_button);
       
        sb = (SlideButton)findViewById(R.id.slideButton);
        sb.setOnCheckChangedListener(new SlideButton.OnCheckChangedListner() {
   
   @Override
   public void onCheckChanged(View v, boolean isChecked) {
    // TODO Auto-generated method stub
    Log.i("aaa", "bbb");
    Context context = null;
    Toast t = Toast.makeText(context, Boolean.toString(isChecked), Toast.LENGTH_LONG);
    t.show();
   }
  });
    }
}

뭐가 문제인건지 고수분들의 조언 부탁드립니다 ㅠㅠ