Custom ListView

Custom Listview comprises of rows that are designed as per the users needs.

For the layout above your customrow.axml file is as shown below

   <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:padding="8dp">
    <ImageView
        android:id="@+id/Image"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:layout_alignParentLeft="true"
        android:layout_marginRight="8dp"
        android:src="@drawable/icon" />
    <TextView
        android:id="@+id/Text1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@id/Image"
        android:layout_toRightOf="@id/Image"
        android:layout_marginTop="5dip"
        android:text="This is Line1"
        android:textSize="20dip"
        android:textStyle="bold" />
    <TextView
        android:id="@+id/Text2"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/Text1"
        android:layout_marginTop="1dip"
        android:text="This is line2"
        android:textSize="15dip"
        android:layout_toRightOf="@id/Image" />
</RelativeLayout>

Then you can design your main.axml, which contains a textview for the header and a listview.

Hope that is easy…

Next create your Data.cs class that will represent your row objects

public class Data
{
    public string Heading;
    public string SubHeading;
    public string ImageURI;

    public Data ()
    {
        Heading = "";
        SubHeading = "";
        ImageURI = "";
    }
}

Next you need the DataAdapter.cs class, Adapters link your data with the underlying view

public class DataAdapter : BaseAdapter<Data> {

    List<Data> items;

    Activity context;
    public DataAdapter(Activity context, List<Data> items)
        : base()
    {
        this.context = context;
        this.items = items;
    }
    public override long GetItemId(int position)
    {
        return position;
    }
    public override Data this[int position]
    {
        get { return items[position]; }
    }
    public override int Count
    {
        get { return items.Count; }
    }
    public override View GetView(int position, View convertView, ViewGroup parent)
    {
        var item = items[position];
        View view = convertView;
        if (view == null) // no view to re-use, create new
            view = context.LayoutInflater.Inflate(Resource.Layout.CustomRow, null);

        view.FindViewById<TextView>(Resource.Id.Text1).Text = item.Heading;
        view.FindViewById<TextView>(Resource.Id.Text2).Text = item.SubHeading;

        var imageBitmap = GetImageBitmapFromUrl(item.ImageURI);
        view.FindViewById<ImageView> (Resource.Id.Image).SetImageBitmap (imageBitmap);
        return view;
    }

    private Bitmap GetImageBitmapFromUrl(string url)
    {
        Bitmap imageBitmap = null;
        if(!(url=="null"))
            using (var webClient = new WebClient())
            {
                var imageBytes = webClient.DownloadData(url);
                if (imageBytes != null && imageBytes.Length > 0)
                {
                    imageBitmap = BitmapFactory.DecodeByteArray(imageBytes, 0, imageBytes.Length);
                }
            }

        return imageBitmap;
    }

}

The most important part is inside the GetView Function, this is where you link your object to your custom row.

The GetImageBitmapFromUrl is not part of the dataadapter but I have put this over here for simplicity.

At last we come to the MainActivity.cs

public class MainActivity : Activity
{

    ListView listView;

    protected override void OnCreate (Bundle bundle)
    {
        base.OnCreate (bundle);

        // Set our view from the "main" layout resource
        SetContentView (Resource.Layout.Main);
        listView = FindViewById<ListView>(Resource.Id.List);

        List<Data> myList = new List<Data> ();

        Data obj = new Data ();
        obj.Heading = "Apple";
        obj.SubHeading = "An Apple a day keeps the doctor away";
        obj.ImageURI = "http://www.thestar.com/content/dam/thestar/opinion/editorials/star_s_view_/2011/10/12/an_apple_a_day_not_such_a_good_idea/apple.jpeg";

        myList.Add (obj);

        Data obj1 = new Data();
        obj1.Heading = "Banana";
        obj1.SubHeading = "Bananas are an excellent source of vitamin B6 ";
        obj1.ImageURI = "http://www.bbcgoodfood.com/sites/bbcgoodfood.com/files/glossary/banana-crop.jpg";

        myList.Add(obj1);

        Data obj2 = new Data();
        obj2.Heading = "Kiwi Fruit";
        obj2.SubHeading = "Kiwifruit is a rich source of vitamin C";
        obj2.ImageURI = "http://www.wiffens.com/wp-content/uploads/kiwi.png";

        myList.Add(obj2);

        Data obj3 = new Data();
        obj3.Heading = "Pineapple";
        obj3.SubHeading = "Raw pineapple is an excellent source of manganese";
        obj3.ImageURI = "http://www.medicalnewstoday.com/images/articles/276/276903/pineapple.jpg";

        myList.Add(obj3);

        Data obj4 = new Data();
        obj4.Heading = "Strawberries";
        obj4.SubHeading = "One serving (100 g)of strawberries contains approximately 33 kilocalories";
        obj4.ImageURI = "https://ecs3.tokopedia.net/newimg/product-1/2014/8/18/5088/5088_8dac78de-2694-11e4-8c99-6be54908a8c2.jpg";

        myList.Add (obj4);
        listView.Adapter = new DataAdapter(this,myList);

    }

Your final project structure is as show below.

If everything is fine you should see the output as shown