Updating listView / refreshing adapter

Question

I have implemented the Universal Image Loader into my app with a gridview layout.

When I press a button I want to add a new imageUrl to the Array of Urls.

I managed to do that, but when I refresh my imageList, I still only see the images that were in the Array on StartUp.

How can I update the gridView with the new Array?

EDIT

MainActivity

public class MainActivity extends Activity {

Button btnView;
private ListView listView;
Socket client;
PrintWriter printwriter;
EditText textField;
Button button;
String messsage;
ObjectInputStream input;
ObjectOutputStream output;
int counter = 1;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();

    StrictMode.setThreadPolicy(policy); 
    setContentView(R.layout.ac_home);

    //startRunning();



}

public void onImageGridClick(View view) {
    Intent intent = new Intent(this, ViewImages.class);
    startActivity(intent);
}


public void onTakeImageClick(View view) throws IOException {
    ViewImages.addImg();
}

 }

And here is the ViewImage class

public class ViewImages extends Activity {

private ListView listView;

ImageLoader loader;
   private static ImageListAdapter adapter; 
   private static List<String> mItems;  

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mItems = new ArrayList<String>();
    mItems.add("http://195.178.234.228/images/image8.jpg");
    mItems.add("http://195.178.234.228/images/image7.jpg");


    adapter = new ImageListAdapter(this, mItems);

    //


    listView = (ListView)findViewById(R.id.listView);
    listView.setAdapter(adapter);
}

public static void addImg(){
    mItems.add("http://195.178.234.228/images/image10.jpg");
    adapter.notifyDataSetChanged(); 

}




}

ImageListAdapter

public class ImageListAdapter extends BaseAdapter {

List<String> list;


int size;

private Context context;
private ImageLoader imageLoader;

public ImageListAdapter(Context context,List<String> list) {
    this.context = context;
    this.list = list;
    imageLoader = ImageLoader.getInstance();
    imageLoader.clearDiscCache();
    imageLoader.clearMemoryCache();
}

@Override
public int getCount() {
    return list.size();
}


@Override
public Object getItem(int arg0) {
    return null;
}



@Override
public long getItemId(int arg0) {
    return 0;
}



@Override
public View getView(int position, View convertView, ViewGroup viewGroup) {
    View v = convertView;

    ViewHolder vh = null;
    if (v == null) {
        v = View.inflate(context, R.layout.list_item, null);

        vh = new ViewHolder();
        vh.imageView = (ImageView) v.findViewById(R.id.imageView);

        v.setTag(vh);
    }
    else {
        vh = (ViewHolder)v.getTag();
    }

    DisplayImageOptions options = new DisplayImageOptions.Builder()
    .cacheOnDisc()
    .build();

    imageLoader.displayImage(list.get(position), vh.imageView, options);

    return v;
}

private class ViewHolder {
    ImageView imageView;
}

}

Answer 1

Your method onTakeImageClick() is not having any effect ,if you need to add image url to your ViewImages Activity the one way would be to pass through intent.putExtra() method.

Intent intent = new Intent(this, ViewImages.class);
intent.putExtra("ImageName" , "ImageUrl");
startActivity(intent);

you can fetch this extra by :-

getIntent().getStringExtra("ImageName");

Other thing is in your imageViewAdapter,the method getItem() returns null instead return

list.get(arg0);

This method will return the view at position arg0.