Multi Select Spinner Xamarin Android - xamarin.android

Question

I am using a spinner and an arrayAdapter to populate items in spinner. I want to make the spinner multi-selectable but I just select one row.I searched in Google, solution available in Java, but i don't have any idea on how to implement it in Xamarin.
My code is as below,
adapterList= new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleListItemMultipleChoice);
spnMultiTest.Adapter = adapterList;

Answer 1

I want to make the spinner multi-selectable but I just select one row.I searched in Google, solution available in Java, but i don't have any idea on how to implement it in Xamarin.
Basically I just translate the codes from Android Spinner with multiple choice
to Xamarin codes. I have tested it and it works fine:
MultiSpinner.cs:
public interface MultiSpinnerListener
{
void onItemsSelected(bool[] selected);
}
public class MultiSpinner : Spinner, IDialogInterfaceOnMultiChoiceClickListener, IDialogInterfaceOnCancelListener
{
Context _context;
private List<String> items;
private bool[] selected;
private String defaultText;
private MultiSpinnerListener listener;
public MultiSpinner(Context context) : base(context)
{
_context = context;
}
public MultiSpinner(Context context, IAttributeSet arg1) : base(context, arg1)
{
_context = context;
}
public MultiSpinner(Context context, IAttributeSet arg1, int arg2) : base(context, arg1, arg2)
{
_context = context;
}
public void OnClick(IDialogInterface dialog, int which, bool isChecked)
{
if (isChecked)
selected[which] = true;
else
selected[which] = false;
}
public override void OnClick(IDialogInterface dialog, int which)
{
dialog.Cancel();
}
public override bool PerformClick()
{
AlertDialog.Builder builder = new AlertDialog.Builder(_context);
builder.SetMultiChoiceItems(
items.ToArray(), selected, this);
builder.SetPositiveButton("OK",this);
builder.SetOnCancelListener(this);
builder.Show();
return true;
}
public void SetItems(List<String> items, String allText,
MultiSpinnerListener listener)
{
this.items = items;
this.defaultText = allText;
this.listener = listener;
// all selected by default
selected = new bool[items.Count];
for (int i = 0; i < selected.Length; i++)
selected[i] = true;
ArrayAdapter<string> adapter = new ArrayAdapter<string>(_context,Resource.Layout.simple_spinner_item,Resource.Id.tv_item,new string[] { allText });
// all text on the spinner
//ArrayAdapter<String> adapter = new ArrayAdapter<String>(_context,Resource.Layout.simple_spinner_item, new String[] { allText });
Adapter = adapter;
}
public void OnCancel(IDialogInterface dialog)
{
Java.Lang.StringBuffer spinnerBuffer = new Java.Lang.StringBuffer();
bool someUnselected = false;
for (int i = 0; i < items.Count; i++)
{
if (selected[i] == true)
{
spinnerBuffer.Append(items[i]);
spinnerBuffer.Append(", ");
}
else
{
someUnselected = true;
}
}
String spinnerText;
if (someUnselected)
{
spinnerText = spinnerBuffer.ToString();
if (spinnerText.Length > 2)
spinnerText = spinnerText.Substring(0, spinnerText.Length - 2);
}
else
{
spinnerText = defaultText;
}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(_context,Resource.Layout.simple_spinner_item,Resource.Id.tv_item,new string[] { spinnerText });
Adapter = adapter;
if (listener != null)
{
listener.onItemsSelected(selected);
}
}
}
simple_spinner_item.xml:
<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/tv_item"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
Update:
Here is the codes for using this MultiSpinner:
Main.axml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<MultiSpinner.MultiSpinner
android:id="#+id/mSpinner"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
MainActivity.cs:
public class MainActivity : Activity
{
MultiSpinner mSpinner;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.Main);
mSpinner = FindViewById<MultiSpinner>(Resource.Id.mSpinner);
List<string> items = new List<string> {
"Android",
"iOS",
"UWP"
};
mSpinner.SetItems(items, "AllText", null);
}
}