Adding Searchview in Listview - xamarin.android

Question

I made an array to transfer the required data consisting of 3 elements(Heading,SubHeading, int ImageResourceId).
The data shows up well in listview but I couldn't do the research inside listview.
I want to do the research using searchview on specific SubHeading or both (Heading,SubHeading)
//on creat
listView.Adapter = new HomeScreenAdapter(this, HomeScreenAdapter.tableItems);
search.QueryTextChange += SearchV_QueryTextChange;
//filter listview
private void SearchV_QueryTextChange(object sender, SearchView.QueryTextChangeEventArgs e)
{
}
//
// 3-class listview item id
public class TableItem
{
public string Heading;
public string SubHeading;
public int ImageResourceId;
public TableItem(string Heading, string SubHeading, int ImageResourceId)
{
this.Heading = Heading;
this.SubHeading = SubHeading;
this.ImageResourceId = ImageResourceId;
}
}
}
//
//class adapter & array item
class HomeScreenAdapter : BaseAdapter<TableItem>
{
public static List<TableItem> tableItems = new List<TableItem>();
List<TableItem> items;
Activity context;
public void filldata()
{
tableItems.Add(new TableItem("hussein", "devepoer", Resource.Drawable.imaga));
tableItems.Add(new TableItem("ahmed", "admin", Resource.Drawable.imagb));
tableItems.Add(new TableItem("jasim", " manager", Resource.Drawable.imagc));
tableItems.Add(new TableItem("ahmed", "admin", Resource.Drawable.imagd));
tableItems.Add(new TableItem("jasim", " manager", Resource.Drawable.image));
tableItems.Add(new TableItem("jasim", " manager", Resource.Drawable.imagf));
}
}

Answer 1

According to your code, I do one sample by SubHeading to filter ListView data.
Firstly, create TableItem class:
public class TableItem
{
public string Heading { get; set; }
public string SubHeading { get; set; }
public int ImageResourceId { get; set; }
}
Then creating UI for ListView item:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView android:id="#+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<TextView android:id="#+id/textView2"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<ImageView android:id="#+id/imageView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
And create Adapter and filter for data:
public class TableItemAdapter : BaseAdapter<TableItem>, IFilterable
{
private List<TableItem> _originalData;
private List<TableItem> _items;
private readonly Activity _context;
public TableItemAdapter(Activity activity, IEnumerable<TableItem> tableitems)
{
_items = tableitems.OrderBy(s => s.SubHeading).ToList();
_context = activity;
Filter = new TableItemFilter(this);
}
public override TableItem this[int position]
{
get { return _items[position]; }
}
public Filter Filter { get; private set; }
public override int Count
{
get { return _items.Count; }
}
public override long GetItemId(int position)
{
return position;
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
var view = convertView ?? _context.LayoutInflater.Inflate(Resource.Layout.TableItem, null);
var tableitem = _items[position];
var HeadingView = view.FindViewById<TextView>(Resource.Id.textView1);
var SubHeadingView = view.FindViewById<TextView>(Resource.Id.textView2);
var imageView = view.FindViewById<ImageView>(Resource.Id.imageView1);
HeadingView.Text = tableitem.Heading;
SubHeadingView.Text = tableitem.SubHeading;
imageView.SetImageResource(tableitem.ImageResourceId);
return view;
}
public override void NotifyDataSetChanged()
{
// If you are using cool stuff like sections
// remember to update the indices here!
base.NotifyDataSetChanged();
}
private class TableItemFilter : Filter
{
private readonly TableItemAdapter _adapter;
public TableItemFilter(TableItemAdapter adapter)
{
_adapter = adapter;
}
protected override FilterResults PerformFiltering(ICharSequence constraint)
{
var returnObj = new FilterResults();
var results = new List<TableItem>();
if (_adapter._originalData == null)
_adapter._originalData = _adapter._items;
if (constraint == null) return returnObj;
if (_adapter._originalData != null && _adapter._originalData.Any())
{
// Compare constraint to all names lowercased.
// It they are contained they are added to results.
results.AddRange(
_adapter._originalData.Where(
item => item.SubHeading.ToLower().Contains(constraint.ToString())));
}
// Nasty piece of .NET to Java wrapping, be careful with this!
returnObj.Values = FromArray(results.Select(r => r.ToJavaObject()).ToArray());
returnObj.Count = results.Count;
constraint.Dispose();
return returnObj;
}
protected override void PublishResults(ICharSequence constraint, FilterResults results)
{
using (var values = results.Values)
_adapter._items = values.ToArray<Java.Lang.Object>().Select(r =>r.ToNetObject<TableItem>()).ToList();
_adapter.NotifyDataSetChanged();
// Don't do this and see GREF counts rising
constraint.Dispose();
results.Dispose();
}
}
}
ObjectExtensions to implement filter:
public class JavaHolder : Java.Lang.Object
{
public readonly object Instance;
public JavaHolder(object instance)
{
Instance = instance;
}
}
public static class ObjectExtensions
{
public static TObject ToNetObject<TObject>(this Java.Lang.Object value)
{
if (value == null)
return default(TObject);
if (!(value is JavaHolder))
throw new InvalidOperationException("Unable to convert to .NET object. Only Java.Lang.Object created with .ToJavaObject() can be converted.");
TObject returnVal;
try { returnVal = (TObject)((JavaHolder)value).Instance; }
finally { value.Dispose(); }
return returnVal;
}
public static Java.Lang.Object ToJavaObject<TObject>(this TObject value)
{
if (Equals(value, default(TObject)) && !typeof(TObject).IsValueType)
return null;
var holder = new JavaHolder(value);
return holder;
}
}
Mainactivity.cs:
public class MainActivity : AppCompatActivity
{
private SearchView searchview1;
private ListView listview1;
private TableItemAdapter tableitemadapter;
private List<TableItem> tableitems;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
Xamarin.Essentials.Platform.Init(this, savedInstanceState);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.activity_main);
searchview1 = FindViewById<SearchView>(Resource.Id.searchView1);
listview1 = FindViewById<ListView>(Resource.Id.listView1);
tableitems = new List<TableItem>()
{
new TableItem(){Heading= "hussein", SubHeading="devepoer",ImageResourceId= Resource.Drawable.plu3 },
new TableItem(){Heading= "ahmed", SubHeading="admin",ImageResourceId= Resource.Drawable.plu3 },
new TableItem(){Heading= "jasim", SubHeading="manager",ImageResourceId= Resource.Drawable.plu3 },
new TableItem(){Heading= "cherry", SubHeading="admin",ImageResourceId= Resource.Drawable.plu3 },
new TableItem(){Heading= "barry", SubHeading="manager",ImageResourceId= Resource.Drawable.plu3 },
new TableItem(){Heading= "annine", SubHeading="manager",ImageResourceId= Resource.Drawable.plu3 }
};
tableitemadapter = new TableItemAdapter(this,tableitems);
listview1.Adapter = tableitemadapter;
searchview1.QueryTextChange += Searchview1_QueryTextChange;
}
private void Searchview1_QueryTextChange(object sender, SearchView.QueryTextChangeEventArgs e)
{
tableitemadapter.Filter.InvokeFilter(e.NewText);
}
public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
{
Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);
base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
}
}
The sample in github:
https://github.com/CherryBu/Searchviewsample
The screenshot: