Android Toast in Kotlin
A Toast is a short alert message shown on the Android screen for a short interval of time. Android Toast is a short popup notification which is used to display information when we perform any operation in our app. In this tutorial, we shall not just limit ourselves by creating a lame toast but also do some user-interactive stuff. First, we shall create a screen with an Edit Text (Text box to take input) and a Button.
Step By Step Implementation to Demonstrate
Step 1: Create a new project
To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio.
Note: Select Kotlin as the programming language.
Step 2: Working with activity_main.xml
In the project window on the left side, navigate to app > res > layout > activity_main.xml.
Here we are going to add an Edit Text and a button. So, remove the hello word Text View in the XML. Now your XML should look like this.
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:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<EditText
android:id="@+id/editText"
android:layout_width="250dp"
android:layout_height="wrap_content"
android:hint="Message"
app:layout_constraintBottom_toTopOf="@+id/button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_chainStyle="packed" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:text="Toast"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/editText" />
</androidx.constraintlayout.widget.ConstraintLayout>
Design UI:
Step 3: Working with MainActivity.kt
Now, Let’s go to the Kotlin class file and make the toast happen. Open the Kotlin class file in app > java > {package-name} > MainActivity.kt
Here, editText is the object for EditText we have created in the Layout file. To get the contents of EditText we have used the text property and stored it in a variable message.
Making a Toast -
Toast.makeText(this, editText.text, Toast.LENGTH_LONG).show()Toast.makeText() creates a toast and returns it and we should pass three parameters:
- context - The context to use. Usually your {@link android.app.Application}or {@link android.app.Activity} object.
- text - The text to show in String format.
- duration - How long to display the message. Either LENGTH_SHORT or LENGTH_LONG
Hiding the Android Soft Keyboard after clicking the Toast button to see a clear Toast
// (OPTIONAL) Function to hide the keyboard
private fun hideKeyboard(activity: Activity) {
// Get the root view of the activity
val view: View = activity.findViewById(R.id.main)
// Get the InputMethodManager service
val imm = activity.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
// Hide the keyboard
imm.hideSoftInputFromWindow(view.windowToken, 0)
}
Add the above method to the main activity class and call it before making toast.
MainActivity.kt:
package org.geeksforgeeks.demo
import android.app.Activity
import android.content.Context
import android.os.Bundle
import android.view.View
import android.view.inputmethod.InputMethodManager
import android.widget.Button
import android.widget.EditText
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// Get reference to the button with the ID "toastButton"
val button: Button = findViewById(R.id.button)
// Set an OnClickListener for the button
button.setOnClickListener {
val editText: EditText = findViewById(R.id.editText)
// Create a toast message with the text from the EditText
Toast.makeText(this, editText.text, Toast.LENGTH_LONG).show()
// Call hideKeyboard function to hide the keyboard
hideKeyboard(this)
}
}
// (OPTIONAL) Function to hide the keyboard
private fun hideKeyboard(activity: Activity) {
// Get the root view of the activity
val view: View = activity.findViewById(R.id.main)
// Get the InputMethodManager service
val imm = activity.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
// Hide the keyboard
imm.hideSoftInputFromWindow(view.windowToken, 0)
}
}
