Wednesday, March 4, 2020

android kotlin - AlertDialog single choice items example

MainActivity.kt 

package com.example.jetpack

import android.os.Bundle
import android.widget.AdapterView.OnItemClickListener
import androidx.appcompat.app.AlertDialog
import androidx.appcompat.app.AppCompatActivity
import com.google.android.material.dialog.MaterialAlertDialogBuilder
import kotlinx.android.synthetic.main.activity_main.*


class MainActivity : AppCompatActivity() {

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

        val context = this

        button.setOnClickListener {
            val builder = MaterialAlertDialogBuilder(context)

            // dialog title
            builder.setTitle("Which is your favorite?")

            val colors = arrayOf(
                "African violet",
                "Alice blue",
                "Alloy orange",
                "Android green",
                "Amaranth pink",
                "Antique bronze"
            )

            // set single choice items
            builder.setSingleChoiceItems(
                colors, // array
                -1 // initial selection (-1 none)
            ){dialog, i ->}


            // alert dialog positive button
            builder.setPositiveButton("Submit"){dialog,which->
                val position = (dialog as AlertDialog).listView.checkedItemPosition
                // if selected, then get item text
                if (position !=-1){
                    val selectedItem = colors[position]
                    textView.text = "Favorite color : $selectedItem"
                }
            }

            // alert dialog other buttons
            builder.setNegativeButton("No",null)
            builder.setNeutralButton("Cancel",null)

            // set dialog non cancelable
            builder.setCancelable(false)

            // finally, create the alert dialog and show it
            val dialog = builder.create()
            dialog.show()

            // initially disable the positive button
            dialog.getButton(AlertDialog.BUTTON_POSITIVE).isEnabled = false

            // dialog list item click listener
            dialog.listView.onItemClickListener =
                OnItemClickListener { parent, view, position, id ->
                    // enable positive button when user select an item
                    dialog.getButton(AlertDialog.BUTTON_POSITIVE)
                        .isEnabled = position != -1
                }
        }
    }
}
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"
    android:id="@+id/constraintLayout"
    tools:context=".MainActivity">

    <com.google.android.material.button.MaterialButton
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:text="Show Dialog"
        android:backgroundTint="#4B5320"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="32dp"
        tools:text="TextView"
        android:textAppearance="@style/TextAppearance.AppCompat.Large"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

</androidx.constraintlayout.widget.ConstraintLayout>
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