ListView

Introduction#

ListView is a viewgroup which groups several items from a data source like array or database and displays them in a scroll-able list. Data are bound with listview using an Adapter class.

Remarks#

ListView is a view group that displays a list of scrollable items.
The list items are automatically inserted to the list using an Adapter that pulls content from a source such as an array or database query and converts each item result into a view that’s placed into the list.

When the content for your layout is dynamic or not pre-determined, you can use a layout that subclasses AdapterView to populate the layout with views at runtime. A subclass of the AdapterView class uses an Adapter to bind data to its layout.

Before using the ListView you should also checking the RecyclerView examples.

Filtering with CursorAdapter

Custom ArrayAdapter

By default the ArrayAdapter class creates a view for each array item by calling toString() on each item and placing the contents in a TextView.

To create a complex view for each item (for example, if you want an ImageView for each array item), extend the ArrayAdapter class and override the getView() method to return the type of View you want for each item.

For example:

public class MyAdapter extends ArrayAdapter<YourClassData>{

    private LayoutInflater inflater;

    public MyAdapter (Context context, List<YourClassData> data){
        super(context, 0, data);
        inflater = LayoutInflater.from(context);
    }

    @Override
    public long getItemId(int position)
    {
        //It is just an example
        YourClassData data = (YourClassData) getItem(position);
        return data.ID;
    }

    @Override
    public View getView(int position, View view, ViewGroup parent)
    {
        ViewHolder viewHolder;
        if (view == null) {
            view = inflater.inflate(R.layout.custom_row_layout_design, null);
            // Do some initialization
        
            //Retrieve the view on the item layout and set the value.
            viewHolder = new ViewHolder(view);
            view.setTag(viewHolder);
         }
         else {
             viewHolder = (ViewHolder) view.getTag();
         }
         
        //Retrieve your object    
        YourClassData data = (YourClassData) getItem(position);
       
        viewHolder.txt.setTypeface(m_Font);    
        viewHolder.txt.setText(data.text);              
        viewHolder.img.setImageBitmap(BitmapFactory.decodeFile(data.imageAddr));
        
        return view;
    
    }

    private class ViewHolder
    {
         private final TextView txt;
         private final ImageView img;

         private ViewHolder(View view) 
         {
             txt = (TextView) view.findViewById(R.id.txt);
             img = (ImageView) view.findViewById(R.id.img);
         }
    }
}

A basic ListView with an ArrayAdapter

By default the ArrayAdapter creates a view for each array item by calling toString() on each item and placing the contents in a TextView.

Example:

ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
        android.R.layout.simple_list_item_1, myStringArray);

where android.R.layout.simple_list_item_1 is the layout that contains a TextView for each string in the array.

Then simply call setAdapter() on your ListView:

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

To use something other than TextViews for the array display, for instance, ImageViews, or to have some of data besides toString() results fill the views, override getView(int, View, ViewGroup) to return the type of view you want. Check this example.