MainActivity.kt
package com.cfsuman.kotlintutorials
import android.os.Bundle
import android.widget.NumberPicker
import android.widget.TextView
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.constraintlayout.widget.ConstraintLayout
import java.text.NumberFormat
import java.util.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// Get the widgets reference from XML layout
val rootLayout = findViewById<ConstraintLayout>(R.id.rootLayout)
val numberPicker = findViewById<NumberPicker>(R.id.numberPicker)
val numberPickerString = findViewById<NumberPicker>(
R.id.numberPickerString)
val numberPickerFormatter = findViewById<NumberPicker>(
R.id.numberPickerFormatter)
val textView = findViewById<TextView>(R.id.textView)
// Set the number picker minimum and maximum value
numberPicker.minValue = 5
numberPicker.maxValue = 10
numberPicker.wrapSelectorWheel = false
// Set number picker value changed listener
numberPicker.setOnValueChangedListener { picker, oldVal, newVal ->
//Display the newly selected number to text view
textView.text = "Selected Value : $newVal"
}
// Display string values to the number picker
// At first, initialize a new array instance with string values
val colors = arrayOf("Red", "Green", "Blue", "Yellow",
"Magenta", "Black", "Pink")
// Set the number picker minimum and maximum values
numberPickerString.minValue = 0
numberPickerString.maxValue = colors.size - 1
// Set the valued to be displayed in number picker
numberPickerString.displayedValues = colors
// Set number picker value change listener
numberPickerString.setOnValueChangedListener { _, _, newVal ->
// Display the picker selected value to text view
textView.text = "Selected Color : ${colors[newVal]}"
}
// Manage the number picker which format value
numberPickerFormatter.minValue = 1;
numberPickerFormatter.maxValue = 10
// Set value programmatically
numberPickerFormatter.value = 5
// Format the value
numberPickerFormatter.setFormatter { i ->
NumberFormat.getCurrencyInstance(
Locale.US
).format(i.toLong())
}
// Number picker value changed listener
numberPickerFormatter.setOnValueChangedListener {
_, _, newVal ->
textView.text = "Formatted Value : $newVal"
}
// Set a click listener for root layout widget
rootLayout.setOnClickListener {
// Display the pickers selected value on a toast message
Toast.makeText(
applicationContext,
"Selected ${numberPicker.value} " +
"and ${colors[numberPickerString.value]}",
Toast.LENGTH_SHORT
).show()
}
}
}
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"
android:id="@+id/rootLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#DCDCDC"
android:padding="24dp">
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="24dp"
android:textSize="24sp"
android:fontFamily="sans-serif"
app:layout_constraintTop_toTopOf="parent" />
<NumberPicker
android:id="@+id/numberPicker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_marginTop="32dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView" />
<NumberPicker
android:id="@+id/numberPickerString"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
app:layout_constraintBottom_toBottomOf="@+id/numberPicker"
app:layout_constraintStart_toEndOf="@+id/numberPicker" />
<NumberPicker
android:id="@+id/numberPickerFormatter"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
app:layout_constraintBottom_toBottomOf="@+id/numberPickerString"
app:layout_constraintStart_toEndOf="@+id/numberPickerString" />
</androidx.constraintlayout.widget.ConstraintLayout>



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