Image slide ViewPager

I'm trying to implement in my application the viewpager to swipe from one image to another. I found a lot of codes in internet but every code take the images from drawable folder. I've got a database with the path of the image on the sdcard so I tried this method to put the image in an array but it won't work saying this

02-22 17:17:23.424: E/AndroidRuntime(6954): FATAL EXCEPTION: main
02-22 17:17:23.424: E/AndroidRuntime(6954): Process: info.androidhive.tabsswipe, PID: 6954
02-22 17:17:23.424: E/AndroidRuntime(6954): java.lang.RuntimeException:  Unable to start activity  ComponentInfo{info.androidhive.tabsswipe/info.androidhive.tabsswipe.ViewActivity W}: java.lang.NullPointerException: Attempt to get length of null array
02-22 17:17:23.424: E/AndroidRuntime(6954):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
02-22 17:17:23.424: E/AndroidRuntime(6954):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
02-22 17:17:23.424: E/AndroidRuntime(6954):     at android.app.ActivityThread.access$800(ActivityThread.java:144)
02-22 17:17:23.424: E/AndroidRuntime(6954):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)

this is my code :

public class ViewActivityW extends Activity {
RegistrationAdapterW regadapter;
ViewPager viewPager;
RegistrationOpenHelperW openHelper;
public long rowID;
Cursor c;
public TextView name;
private TextView coff;
private TextView desc;
public EditText viewimg1, viewimg2;
TouchImageView img1;
public String[] imageId;
public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.view_w);
      name = (TextView) findViewById(R.id.et_viewfnamew);
      coff = (TextView) findViewById(R.id.et_viewdescw);
      desc = (TextView) findViewById(R.id.et_viewlnamew);
      Bundle extras = getIntent().getExtras();
      rowID = extras.getLong(WeedFragment.ROW_ID);
      viewPager = (ViewPager) findViewById(R.id.viewPager);
      PagerAdapter adapter = new CustomAdapter(ViewActivityW.this);
      viewPager.setAdapter(adapter);

}

@Override
protected void onResume() {
    super.onResume();

    // Execute LoadNotes() AsyncTask
    new LoadNotes().execute(rowID);
}
private class LoadNotes extends AsyncTask<Long, Object, Cursor> {
    // Calls DatabaseConnector.java class
    RegistrationAdapterW dbConnector = new RegistrationAdapterW(ViewActivityW.this);

    @Override
    protected Cursor doInBackground(Long... params) {
        // Pass the Row ID into GetOneNote function in
        // DatabaseConnector.java class
        dbConnector.opnToWrite();
        return dbConnector.GetOneNote(params[0]);
    }

    @Override
    protected void onPostExecute(Cursor c) {
        super.onPostExecute(c);

        c.moveToFirst();

        // Set the Text in TextView
        name.setText(c.getString(1));
        coff.setText(c.getString(2));
        desc.setText(c.getString(3));
        imageId = new String[] {c.getString(5), c.getString(6)};

        c.close();
        dbConnector.Close();
    }
}
public class CustomAdapter extends PagerAdapter{

       Context context;
       ViewActivityW view;


       public CustomAdapter(Context context){
           this.context = context;

       }


       @Override
       public Object instantiateItem(ViewGroup container, int position) {
           // TODO Auto-generated method stub

           LayoutInflater inflater = ((Activity)context).getLayoutInflater();

           View viewItem = inflater.inflate(R.layout.image_item, container, false);
           ImageView imageView = (ImageView) viewItem.findViewById(R.id.imageView);
           imageView.setImageBitmap(BitmapFactory.decodeFile(view.imageId[position]));
           //TextView textView1 = (TextView) viewItem.findViewById(R.id.textView1);
           //textView1.setText("hi");
           ((ViewPager)container).addView(viewItem);

           return viewItem;
       }

       @Override
       public int getCount() {
           // TODO Auto-generated method stub
           return imageId.length;
       }

       @Override
       public boolean isViewFromObject(View view, Object object) {
           // TODO Auto-generated method stub

           return view == ((View)object);
       }


       @Override
       public void destroyItem(ViewGroup container, int position, Object object) {
           // TODO Auto-generated method stub
           ((ViewPager) container).removeView((View) object);
       }

    }

}

What I made wrong? Can someone help me?