Dropdown items inside of fragment are not showing

Question

I am trying to implement a dropdown with an AutoCompleteTextView which is located inside of a fragment in my Android App. Right now, the dropdown items are not showing. Instead a keyboard is appearing. How can I fix the code to not show the keyboard but instead show the options 1 to 4 and let the user select the desired one?

This is the important code (ContentFragment.kt):

package com.example.myapplication

import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ArrayAdapter
import kotlinx.android.synthetic.main.fragment_content.*

class ContentFragment : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {

        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_content, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val items = listOf("Option1", "Option2", "Option3", "Option4")
        val adapter = ArrayAdapter(this.requireContext(), R.layout.dropdown_example_data_items, items)

        dropdownField.setAdapter(adapter)
    }
}

Here is some more stuff which is probably not so important:

MainActivity.kt:

package com.example.myapplication

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
}

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="vertical">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="56dp"
        app:layout_constraintBottom_toBottomOf="parent">

        <fragment
            android:id="@+id/fragment"
            class="com.example.myapplication.ContentFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />

    </androidx.constraintlayout.widget.ConstraintLayout>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:text="Button outside of fragment"
        app:layout_constraintBottom_toBottomOf="parent"
        />

</androidx.constraintlayout.widget.ConstraintLayout>

fragment_content.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ContentFragment">

    <ScrollView
        android:id="@+id/ScrollView_Data"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/material_dynamic_neutral50"
        >

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:paddingHorizontal="5dp">

            <com.google.android.material.textfield.TextInputLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content">

                <AutoCompleteTextView
                    android:id="@+id/dropdownField"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="Option1"
                    />

            </com.google.android.material.textfield.TextInputLayout>

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/TestButton"
                android:text="Button inside of fragment"
                tools:ignore="MissingConstraints"/>

        </LinearLayout>

    </ScrollView>

</androidx.constraintlayout.widget.ConstraintLayout>

dropdown_example_data_items:

<TextView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:ellipsize="end"
    android:maxLines="1"

    />

And this is the result when the AutoCompleteTextView is tapped:

Answer 1

Use AutoCompleteTextView with Material TextInputLayout as follow

<com.google.android.material.textfield.TextInputLayout
    android:id="@+id/lt_options"
    style="@style/Widget.MaterialComponents.TextInputLayout.FilledBox.ExposedDropdownMenu"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Select Options">

    <AutoCompleteTextView
                android:id="@+id/dropdownField"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Option1"
                android:inputType="none" />

</com.google.android.material.textfield.TextInputLayout>

In your class, set adapter

val items = listOf("Option1", "Option2", "Option3", "Option4")
val adapter = ArrayAdapter(view.context, R.layout.dropdown_example_data_items, items)
dropdownField.setAdapter(adapter)

Reference Link