How to view an image from a list of images Android?

Question

I am working on an application that saves images to a directory and then allows you to view those images. Currently I am able to save images and then view a list of the images within that directory. I want to be able to open an image in an imageview when the user selects the image file from the list. Here is the code I currently have for the list:

public class Test extends ListActivity {

    private List<String> fileList = new ArrayList<String>();

    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);


        String root = Environment.getExternalStorageDirectory().toString();
        File mapfiles= new File(root + "/Maps"); 
        ListDir(mapfiles);

    }

    void ListDir(File f) {

        File[] files = f.listFiles();
        fileList.clear();

        for (File file : files) { 
            //fileList.add(file.getPath());  
            fileList.add(file.getName());
        }

        ArrayAdapter<String> directoryList = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, fileList);
        setListAdapter(directoryList); 

    }

    protected void onListItemClick(ListView l, View v, int position, long id) {
        String item=fileList.get(position).toString();
        Toast.makeText(Test.this, "You clicked on: "+item, Toast.LENGTH_SHORT).show();

    }

}

I used toast just to verify that I could get something to happen when clicking on an item in the list, and that is working. The code I tried to use within the onItemListClick is:

File selected = new File(fileList.get(position));

if(selected.isDirectory()){
    ListDir(selected);
} else {
    Uri selectedUri = Uri.fromFile(selected);
    Intent notificationIntent = new Intent(Intent.ACTION_VIEW, selectedUri);                        
    startActivity(notificationIntent);
}

That causes the app to crash and I'm not sure why. My question is what is incorrect in the above code? Or simply how can I view an image by selecting it from my list?

Thanks.