ImageButton in Kotlin

Android ImageButton is a user interface widget which is used to display a button having image and to perform exactly like button when we click on it but here, we add an image on Image button instead of text. There are different types of buttons available in android like ImageButton, ToggleButton etc.

We can add an image to the button simply by using attribute android:src in activity_main.xml file or by using setImageResource() method.

In android, we can create ImageButton control in two ways either manually or programmatically.

First we create a new project by following the below steps:

1. Click on File, then New => New Project.
2. After that include the Kotlin support and click on next.
3. Select the minimum SDK as per convenience and click next button.
4. Then select the Empty activity => next => finish.

Different attributes of Switch widget

XML Attributes	Description
android:id	Used to uniquely identify the control.
android:src	Used to specify the source file of the image.
android:onClick	Used to Specifies what to do when this button is clicked.
android:visibility	Used to set visibility of the image button.
android:background	Used to set background color of the Image button.
android:maxHeight	Used to set maximum height of the Image button view.
android:maxWidth	Used to set maximum width of the Image button view.
android:padding	Used to set the padding from left, right, top and bottom.

Use ImageBotton in activity_main.xml file

In this file, we include the Edittext and ImageButton and set their attributes like id, layout_width, hint etc.

XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/linear_layout">

    <EditText
        android:id="@+id/Num1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="50dp"
        android:ems="10"
        android:hint= "Enter first number"/>

    <EditText
        android:id="@+id/Num2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="50dp"
        android:ems="10"
        android:hint= "Enter second number"/>

    <ImageButton
        android:id="@+id/imageBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="100dp"
        android:src="@android:drawable/btn_plus" />
</LinearLayout>

Modify the strings.xml file to add application name

XML

<resources>
    <string name="app_name">ImageButtonInKotlin</string>
</resources>

Access ImageButton and EditText in MainActivity.kt file

First of all, we declare two variables num1 and num2 for both edittext and access them using the ids.

val num1 = findViewById(R.id.Num1)
val num2 = findViewById(R.id.Num2)

then, we declare variable imgbtn for the ImageButton and set the OnCLickListener to check the filled is empty or not

val imgbtn = findViewById(R.id.imageBtn)
    imgbtn.setOnClickListener {
     if (num1.text.toString().isEmpty() || num2.text.toString().isEmpty()) {
          Toast.makeText(applicationContext,
           "Enter both numbers", Toast.LENGTH_SHORT).show()
    }

Kotlin

package com.geeksforgeeks.myfirstkotlinapp

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import android.widget.EditText
import android.widget.ImageButton
import android.widget.Toast


class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val num1 = findViewById<EditText>(R.id.Num1)
        val num2 = findViewById<EditText>(R.id.Num2)
        val imgbtn = findViewById<ImageButton>(R.id.imageBtn)
        imgbtn.setOnClickListener {
         if (num1.text.toString().isEmpty() || num2.text.toString().isEmpty()) {
              Toast.makeText(applicationContext,
                  "Enter both numbers", Toast.LENGTH_SHORT).show()
            }
            else {
                val num1 = Integer.parseInt(num1.text.toString())
                val num2 = Integer.parseInt(num2.text.toString())
                Toast.makeText(applicationContext,
                    "Sum of the numbers = " + (num1 + num2),
                    Toast.LENGTH_SHORT).show()
            }
        }
    }
}

AndroidManifest.xml file

XML

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.geeksforgeeks.myfirstkotlinapp">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

</manifest>

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