How to always display vertical scrollbar in spinner when open it? Explain with example

 The vertical scrollbar in a Spinner widget in Android is typically displayed automatically when there are enough items in the Spinner to require scrolling. Android does not provide a built-in option to always display the vertical scrollbar when the Spinner is open. However, you can create a custom Spinner-like view that always shows the scrollbar when opened.

Here's an example of how you can achieve this by creating a custom Spinner-like view using a PopupWindow and a ListView:

1. Create a Custom Spinner Layout:

   Create a custom layout for your Spinner-like view (e.g., custom_spinner_layout.xml). In this layout, you can include a ListView with vertical scrollbars. Here's a basic example:

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<!-- custom_spinner_layout.xml -->

<ListView

    android:id="@+id/customSpinnerListView"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:scrollbars="vertical" />

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Create a Custom Spinner Class:

Create a custom class (e.g., CustomSpinner) to manage the behavior of your custom Spinner-like view. In this class, you can create a PopupWindow to display the custom view:

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import android.content.Context;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ArrayAdapter;

import android.widget.ListView;

import android.widget.PopupWindow;

import java.util.List;

public class CustomSpinner {

    private final Context context;

    private final PopupWindow popupWindow;

    private final ListView listView;

    public CustomSpinner(Context context, List<String> itemList) {

        this.context = context;

        View customView = LayoutInflater.from(context).inflate(R.layout.custom_spinner_layout, null);

        popupWindow = new PopupWindow(customView, ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);

        popupWindow.setFocusable(true);

        listView = customView.findViewById(R.id.customSpinnerListView);

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

        listView.setAdapter(adapter);

    }

    public void show(View anchor) {

        popupWindow.showAsDropDown(anchor);

    }

    public void dismiss() {

        popupWindow.dismiss();

    }

}

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Using the Custom Spinner:

In your activity, you can create an instance of the custom spinner and display it when needed. For example:

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List<String> items = new ArrayList<>();

items.add("Item 1");

items.add("Item 2");

items.add("Item 3");

CustomSpinner customSpinner = new CustomSpinner(this, items);

// Display the custom spinner when a button is clicked

Button openSpinnerButton = findViewById(R.id.openSpinnerButton); // Replace with your button

openSpinnerButton.setOnClickListener(new View.OnClickListener() {

    @Override

    public void onClick(View v) {

        customSpinner.show(v);

    }

});

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1. In this example, when the button is clicked, the custom spinner is displayed, and it will always show vertical scrollbars when open.

By creating a custom Spinner-like view with vertical scrollbars, you can control the scrollbar's visibility and display it whenever the custom Spinner is opened.