android kotlin - EditText example

MainActivity.kt

package com.cfsuman.kotlintutorials

import android.os.Bundle
import android.text.Editable
import android.text.TextWatcher
import android.widget.*
import androidx.appcompat.app.AppCompatActivity


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

        // Get the widgets reference from XML layout
        val tvOutput = findViewById<TextView>(R.id.tvOutput)
        val editText = findViewById<EditText>(R.id.editText)
        val buttonSet = findViewById<Button>(R.id.buttonSet)
        val buttonGet = findViewById<Button>(R.id.buttonGet)
        val buttonClear = findViewById<Button>(R.id.buttonClear)

        // Set some text to the EditText
        buttonSet.setOnClickListener{
            editText.setText("Jones")
        }


        // Get the EditText text on button click event
        buttonGet.setOnClickListener{
            // Ensure that the EditText is not empty
            val inputtedText = editText.text
            if(inputtedText.isNotEmpty()){ // EditText validation
                // Display the EditText text in toast message
                tvOutput.text = "Get Text : $inputtedText"
            }else{
                tvOutput.text = "EditText is empty"
            }
        }


        // Empty the edit text
        buttonClear.setOnClickListener{
            editText.text.clear()
            //editText.setText("")
        }


        // Set a text change listener for edit text object
        editText.addTextChangedListener(object: TextWatcher {
            override fun afterTextChanged(p0: Editable?) {
                // Do something after text changed
            }

            override fun beforeTextChanged(
                p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
                // Do something before text changed on EditText
            }

            override fun onTextChanged(
                p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
                // Do something on text changed in EditText
                // Display the EditText change text on TextView real time
                if (editText.text.trim().isEmpty()){
                    tvOutput.text = "EditText is empty"
                }else{
                    tvOutput.text = editText.text
                }
            }
        })
    }
}

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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#DCDCDC"
    android:padding="24dp">

    <TextView
        android:id="@+id/tvOutput"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:fontFamily="sans-serif"
        android:textStyle="italic"
        android:padding="12dp"
        android:textSize="22sp"
        android:background="#EAEAEA"
        android:textAlignment="center"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/editText"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:hint="Input your name here"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvOutput" />

    <Button
        android:id="@+id/buttonSet"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="Set Text"
        app:layout_constraintStart_toStartOf="@+id/editText"
        app:layout_constraintTop_toBottomOf="@+id/editText" />

    <Button
        android:id="@+id/buttonGet"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:text="Get Text"
        app:layout_constraintBottom_toBottomOf="@+id/buttonSet"
        app:layout_constraintStart_toEndOf="@+id/buttonSet" />

    <Button
        android:id="@+id/buttonClear"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:text="Clear"
        app:layout_constraintBottom_toBottomOf="@+id/buttonGet"
        app:layout_constraintStart_toEndOf="@+id/buttonGet" />

</androidx.constraintlayout.widget.ConstraintLayout>