Display Toast in Android

A toast is a small popup message that appears on the screen. A toast can inform about running processes and automatically disappears after a few seconds. The size of toast depends on the space required for the message. A toast is not clickable.

A layout XML file contains a Button that displays a toast when it was pressed.

app/src/main/res/layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".MainActivity">

    <Button
        android:id="@+id/myButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Open" />

</RelativeLayout>

A toast can be created using the method Toast.makeText(). The last parameter is duration, which defines how long to display a toast.

We can display the toast by using show() method.

app/src/main/java/com/example/app/MainActivity.kt

package com.example.app

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import kotlinx.android.synthetic.main.activity_main.*

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

    private fun showToast()
    {
        val toast = Toast.makeText(this, "Hello world", Toast.LENGTH_LONG)
        toast.show()
    }
}