Create An Android RatingBar Programmatically in Kotlin

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Hello Readers! In this post, we are going to learn about how to use android ratingBar programmatically in kotlin in any android application. We will also learn about how to add ratingBar widget in linearLayout programmatically in android application.

Output

Tutorialwing Android Dynamic RatingBar Output Android RatingBar Programmatically in Kotlin

Tutorialwing Android Dynamic RatingBar Output

Getting Started

At first, we will create android project. Then, we will create and use ratingBar programmatically in kotlin file.

1. Creating New Project in Kotlin

Follow the steps below to create new project. Please ignore the steps if you have already created a new project.

Step Description
1. Open Android Studio.
2. Go to File => New => New Project. Write application name as DynamicRatingBar. Then, check Include Kotlin Support and click next button.
3. Select minimum SDK you need. However, we have selected 17 as minimum SDK. Then, click next button
4. Then, select Empty Activity => click next => click finish.
5. At this point, You will get a newly created android project successfully.

Now, we will modify xml and kotlin file to use android ratingBar programmatically in kotlin.

2. Modify Values Folder

No values folder have been modified. So, we are not going to mention them here.

3. Modify Layout Folder

Open res/layout/activity_main.xml file. Then, add below code into it.

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

	<LinearLayout
		android:id="@+id/rootContainer"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:orientation="vertical">

	</LinearLayout>

	<Button
		android:id="@+id/button"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:text="Submit"/>

</LinearLayout>

In activity_main.xml file, we have defined a linearLayout, with id rootContainer, that will act as container for the ratingBar created dynamically in the application. We have also defined a button that will show a toast message whenever it is clicked.

4. Create Android RatingBar Programmatically / Dynamically in Kotlin

Open app/src/main/java/com.tutorialwing.dynamicratingbar/MainActivity.kt file. Then, add below code into it.

package com.tutorialwing.dynamicratingbar

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.view.ViewGroup
import android.widget.Button
import android.widget.LinearLayout
import android.widget.RatingBar
import android.widget.Toast

class MainActivity : AppCompatActivity() {

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

        // Create rating bar programmatically...
        val ratingBar = RatingBar(this)
        val layoutParams = LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)
        layoutParams.setMargins(30, 30, 30, 30)
        ratingBar.layoutParams = layoutParams
        ratingBar.stepSize = 0.5.toFloat()

        val linearLayout = findViewById<LinearLayout>(R.id.rootContainer)
        // Add RatingBar to LinearLayout
        linearLayout?.addView(ratingBar)

        val button = findViewById<Button>(R.id.button)
        button?.setOnClickListener {
            val msg = ratingBar.rating.toString()
            Toast.makeText(this@MainActivity, msg, Toast.LENGTH_SHORT).show()
        }
    }
}

In MainActivity.kt file, we have defined a ratingBar widget in the application. Then, we have set it’s params, step and margin. After that, we have added this ratingBar widget in linearLayout. At last, we have set a click listener to show toast message, displaying currently selected rating in the ratingBar, whenever it is clicked.

Since AndroidManifest.xml file is very important in any android application, we are also going to see the content inside this file.

AndroidManifest.xml file

Code inside src/main/AndroidManifest.xml file is –

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

	<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>

When we run the program, we will get output as shown above.

That’s end of our tutorial on Creating Android RatingBar Programmatically in Kotlin.

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We have recently published 100+ articles on android tutorials with kotlin and java. If you need, you may visit Android Tutorial for beginners page. You can also check Kotlin Tutorial for beginners