Customize Spinner - Kotlin

Spinner containing week days, select the default day depending on the device day,

and customize background.

 

Demo:

Xml File:

Drawable code:

<?xml version="1.0" encoding="utf-8"?>
<selector
 xmlns:android="http://schemas.android.com/apk/res/android">

    <item>
        <layer-list>
            <item>
                <shape android:shape="rectangle">
                    <corners android:radius="10dp"/>
                    <padding android:right="10dp"/>
                    <solid android:color=
                        "@color/spinner_transparent_background"/>
                </shape>
            </item>
            <item android:drawable="@drawable/ic_drop_down"
                android:gravity="right|center_vertical">
            </item>
        </layer-list>
    </item>
</selector>

Layout code:

<Spinner
    android:id="@+id/spinner"
    android:background="@drawable/style_dropdown"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:overlapAnchor="false"
    android:layout_margin="20dp" />

//

 This code will show the dropdown menu below the layout

    android:overlapAnchor="false"
Main File:
MainActivity Code:

lateinit var spinner: Spinner

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


    spinner = findViewById(R.id.spinner)

    
    spinnerSet()
}


// Array that defines days of the week.
var weekdays = arrayOf(
    "Saturday",
    "Sunday",
    "Monday",
    "Tuesday",
    "Wednesday",
    "Thursday",
    "Friday"
)

fun getCurrentDay(): Int {
    val calendar = Calendar.getInstance()
    val day = calendar[Calendar.DAY_OF_WEEK]

    return when (day) {
        Calendar.SUNDAY -> 1
        Calendar.MONDAY -> 2
        Calendar.TUESDAY -> 3
        Calendar.WEDNESDAY -> 4
        Calendar.THURSDAY -> 5
        Calendar.FRIDAY -> 6
        Calendar.SATURDAY -> 0
        else -> 1
    }
}

fun spinnerSet() {

    val adapter = ArrayAdapter<String>(
        applicationContext!!,
        R.layout.text_spinner,
        weekdays
    )
    adapter.setDropDownViewResource(R.layout.text_spinner)

    spinner.adapter = adapter
    spinner.setSelection(getCurrentDay())
    spinner.onItemSelectedListener = 
        object : AdapterView.OnItemSelectedListener {
            override fun onNothingSelected(p0: AdapterView<*>?) {

            }
            override fun onItemSelected
                (p0: AdapterView<*>?, p1: View?, p2: Int, p3: Long) {
                    val day = weekdays[p2]
                    Toast.makeText(applicationContext!!,
                                 day, Toast.LENGTH_LONG).show()
            }
    }

}