Create An Android Spinner Programmatically in Kotlin

In this article, we will learn how to create android Spinner programmatically in Kotlin. We will go through various steps that explains how to create Spinner and add it in kotlin file, use different attributes to customise it etc. in any android application. For example, how to set text in Spinner programmatically, how to set id of Spinner, how to capitalise text of Spinner dynamically etc. We will get answer to all such questions in this post.

Learn to use Different Attributes of Spinner in XML File to Customize it.

Output

Tutorialwing Android Dynamic Spinner Output Android Spinner programmatically in kotlin

Tutorialwing Android Dynamic Spinner Output

Getting Started

We can define android Spinner widget as below –

Android spinner is a widget that have multiple options as list in the dropdown, but finally shows option selected by the user.

Now, how do we use Spinner in android application ?

Creating New Project

Follow steps below to create any android project in Kotlin –

Step Description
1. Open Android Studio (Ignore if already done).
2. Go to File => New => New Project. This will open a new window. Then, under Phone and Tablet section, select Empty Activity. Then, click Next.
3. In next screen, select project name as Dynamic Spinner. Then, fill other required details.
4. Then, clicking on Finish button creates new project.

Newbie in Android ?
Some very important concepts (Recommended to learn before you move ahead)

Before we move ahead, we need to setup for viewBinding to access Spinner in Kotlin file without using findViewById() method.

Setup ViewBinding

Add viewBinding true in app/build.gradle file.

 
 android { 
 	// OTHER CODE... 
 	buildFeatures { 
 		viewBinding true 
 	} 
 } 
 

Now, set content in activity using view binding.
Open MainActivity.kt file and write below code in it.

 
 class MainActivity : AppCompatActivity() { 
 	
 	private lateinit var binding: ActivityMainBinding 
 	
 	override fun onCreate(savedInstanceState: Bundle?) { 
 		super.onCreate(savedInstanceState) 
 		binding = ActivityMainBinding.inflate(layoutInflater) 
 		val view = binding.root 
 		setContentView(view) 
 	} 
 } 
 

Now, we can access view in Kotlin file without using findViewById() method.

Since we have a new project, we will modify the xml and class file to use Spinner programmatically in kotlin. Please follow the steps below.

2. Modify Values Folder

Open res/values/strings.xml file. Add below code into it.

<resources>
    <string name="app_name">DynamicSpinner</string>
    <string name="selected_item">Selected item:</string>
</resources>

Other values folders have not been changed. So, we are not going to mention it here.

3. Modify Layout Folder

Open res/layout/activity_main.xml file. Add below code into it.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    android:id="@+id/rootContainer"
    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>

In activity_main.xml file, we have defined a linearLayout, with id rootContainer, that will act as container for the spinner widget created dynamically in the application. Now, we will create android spinner programmatically in kotlin file in the application.

4. Create Android Spinner programmatically in Kotlin

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

package com.tutorialwing.dynamicspinner

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.view.ViewGroup
import android.widget.*
import com.tutorialwing.dynamicspinner.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

	private lateinit var binding: ActivityMainBinding

	override fun onCreate(savedInstanceState: Bundle?) {
		super.onCreate(savedInstanceState)
		binding = ActivityMainBinding.inflate(layoutInflater)
		val view = binding.root
		setContentView(view)

		addSpinner()
	}

	private fun addSpinner() {
		val spinner = Spinner(this)
		spinner.layoutParams = LinearLayout.LayoutParams(
			ViewGroup.LayoutParams.WRAP_CONTENT,
			ViewGroup.LayoutParams.WRAP_CONTENT
		)

		val personNames = arrayOf("Rahul", "Jack", "Rajeev", "Aryan", "Rashmi", "Jaspreet", "Akbar")
		val arrayAdapter = ArrayAdapter(this, android.R.layout.simple_spinner_item, personNames)
		spinner.adapter = arrayAdapter

		spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
			override fun onItemSelected(
				parent: AdapterView<*>,
				view: View,
				position: Int,
				id: Long
			) {
				Toast.makeText(
					this@MainActivity,
					getString(R.string.selected_item) + " " + personNames[position],
					Toast.LENGTH_SHORT
				).show()
			}

			override fun onNothingSelected(parent: AdapterView<*>) {
				// Code to perform some action when nothing is selected
			}
		}

		// Add Spinner to LinearLayout
		binding.rootContainer.addView(spinner)
	}
}

Finally, when you run the application, you will get output as shown above.

Tutorialwing Android Dynamic Spinner Output Android Spinner programmatically in kotlin

Tutorialwing Android Dynamic Spinner Output

Now, Let’s check how to use different attributes of Spinner to customize it dynamically –

Set Id of Spinner

Follow steps below to set id of Spinner programmatically –

  • Create ids.xml file in res/values folder. Then, add below code into it –
    <?xml version="1.0" encoding="utf-8"?>
    <resources>
        <item type="id" name="spinner_ID" />
    </resources>
    
  • Now, we can set id of Spinner dynamically, in MainActivity.kt file, as –

    spinner.id = R.id.spinner_ID  // Spinner
    

    Here, we have set id of Spinner using property access syntax – spinner.id

Learn to Set ID of Spinner Using XML Attribute

Set Width and Height of Spinner

We use layoutParams to set width and height of any View programmatically. In this article, we have added Spinner in LinearLayout. So, we will define LayoutParams as below –

spinner.layoutParams = LinearLayout.LayoutParams(
	ViewGroup.LayoutParams.WRAP_CONTENT,
	ViewGroup.LayoutParams.WRAP_CONTENT
)

Here, we have set width and height as WRAP_CONTENT. Some of possible values for width and height are –

  • WRAP_CONTENT: Sets value of width or height depending on text inside it.
  • MATCH_PARENT: Sets value of width of height depending on width or height of parent layout . i.e. width or height of Spinner will be same as width or height of parent layout.
  • Fixed Value: Sets width or height as per value provided.

Learn to Set Width or Height of Spinner Using XML Attribute

Set Padding of Spinner

Follow steps below to set padding of Spinner Dynamically –

  • If there is no dimens.xml file, create dimens.xml file in res/values folder. Then, add below code in it –
    <?xml version="1.0" encoding="utf-8"?>
    <resources>
        <dimen name="text_padding">16dp</dimen>
    </resources>
    
  • Now, we can set padding of Spinner dynamically, in MainActivity.kt file, as –
    val padding = resources.getDimension(R.dimen.text_padding).toInt()
    spinner.setPadding(padding, padding, padding, padding)
    

    Here, we have accessed dimension defined in dimens.xml using getDimension() method. Then, set padding of Spinner using setPadding() method.

Learn to Set Padding of Spinner Using XML Attribute

Set Margin of Spinner

Follow steps below to set margin of Spinner Dynamically –

  • If there is no dimens.xml file, create dimens.xml file in res/values folder. Then, add below code in it –
    <?xml version="1.0" encoding="utf-8"?>
    <resources>
        <dimen name="text_margin">16dp</dimen>
    </resources>
    
  • Now, we can set margin of Spinner dynamically, in MainActivity.kt file, as –
    val margin = resources.getDimension(R.dimen.text_margin).toInt()
    val layoutParams = LinearLayout.LayoutParams(
    	ViewGroup.LayoutParams.WRAP_CONTENT,
    	ViewGroup.LayoutParams.WRAP_CONTENT
    )
    layoutParams.setMargins(margin, margin, margin, margin)
    spinner.layoutParams = layoutParams
    

    Here, we have accessed dimension defined in dimens.xml using getDimension() method. Then, we have defined layoutParams, set margin to layoutParams. After that, set layoutParams to Spinner.

Learn to Set Margin of Spinner Using XML Attribute

Set Background of Spinner

Follow steps below to set background of Spinner programmatically –

  • If there is no colors.xml file, create colors.xml file in res/values folder. Then, add below code in it –
    <?xml version="1.0" encoding="utf-8"?>
    <resources>
        <color name="purple_200">#FFBB86FC</color>
    </resources>
    
  • Now, we can set background of Spinner dynamically, in MainActivity.kt file, as –
    val color = ContextCompat.getColor(this, R.color.purple_200)
    spinner.setBackgroundColor(color)
    

    Here, we used setBackgroundColor() method to set background color in spinner.

Learn to Set Background of Spinner Using XML Attribute

Set Visibility of Spinner

We can set visibility of Spinner programmatically as –

spinner.visibility = View.VISIBLE

Here, we have set visibility of Spinner using spinner.visibility attribute. Visibility can be of three types – gone, visible and invisible.
Learn to Set Visibility of Spinner Using XML Attribute

Set Text of Spinner

Follow steps below to set text of Spinner programmatically –

  • If there is no strings.xml file, create strings.xml file in res/values folder. Then, add below code in it –
    <resources>
        <string name="click_on_me">Click on me</string>
    </resources>
    
  • Now, we can set text of Spinner dynamically, in MainActivity.kt file, as –
    spinner.text = getString(R.string.click_on_me)
    

    Here, we used spinner.text to set text in spinner.

Learn to Set Text of Spinner Using XML Attribute

Set Color of Text of Spinner

Follow steps below to set color of text of Spinner programmatically in Kotlin –

  • If there is no colors.xml file, create colors.xml file in res/values folder. Then, add below code in it –
    <?xml version="1.0" encoding="utf-8"?>
    <resources>
        <color name="black">#FF000000</color>
    </resources>
    
  • Now, we can set color of text of Spinner dynamically, in MainActivity.kt file, as –
    val textColor = ContextCompat.getColor(this, R.color.black)
    spinner.setTextColor(textColor)
    

    Here, we used setTextColor() method to set color of Spinner of spinner.

Learn to Set Color of Spinner Using XML Attribute

Set Gravity of Spinner

We can set gravity of text of Spinner programmatically in Kotlin as –

spinner.gravity = Gravity.CENTER

Here, we have set gravity of Spinner as center. So, all the text of Spinner will be center aligned.
We can also apply multiple gravity values as –

spinner.gravity = Gravity.CENTER_HORIZONTAL or Gravity.BOTTOM

Here, we have applied multiple gravity values, in Kotlin, to Spinner. In above case, text will be aligned as horizontally centered to bottom.
Learn to Set Margin of Spinner Using XML Attribute

Set Text in Uppercase or Lowercase

Follow steps below to set text in uppercase or lowercase programmatically as –

  • Set Text in Uppercase

    We use spinner.isAllCaps attributes to set text in uppercase or normal. If it is true, text will be set in uppercase.

    spinner.text = "Hello Tutorialwing"
    spinner.isAllCaps = true
    

    In Above case, “Hello Tutorialwing” will be set in Uppercase to Spinner. So, text will be “HELLO TUTORIALWING”.

  • By default, isAllCaps is false. So, whatever is written, text will be set as it is. For example,

    spinner.text = "Hello Tutorialwing"
    spinner.isAllCaps = false. // By default it is false. Written here for example.
    

    Above code will set text, “Hello Tutorialwing”, to Spinner without changing it to Uppercase.

    Actually, if isAllCaps is false, text is set as it is. It neither changes to uppercase nor lowercase.

    How do we set text in lowercase?

    Answer –

    • In xml file – write all the text in lowercase.
    • In kotlin file – take text as string. Then, convert it in lowercase. Then, set it to spinner.

Learn to Set Text in Uppercase or Lowercase Using XML Attribute

Set Size of Text in Spinner

Follow steps below to set size of Spinner programmatically using spinner.textSize attribute –

  • Open res/values/dimens.xml file. Then, add below font-size in it –
    <dimen name="text_size">16sp</dimen>
    
  • Now, using spinner.textSize attribute, we can set size of text dynamically as –

    spinner.textSize = resources.getDimension(R.dimen.text_margin)
    

Learn to Set Size of Text in Spinner Using XML Attribute

Set Style (Bold/italic) of Text in Spinner

We can set textStyle of Spinner programmatically as –

spinner.typeface = Typeface.DEFAULT_BOLD;

In above case, we have set textStyle as bold. So, text of Spinner will be displayed as bold letters.

If we want to preserve previous textStyle too, we can do it as –

spinner.setTypeface(spinner.typeface, Typeface.BOLD);

Learn to Set Typeface of Spinner Using XML Attribute

Set Letter Spacing of Text in Spinner

Follow steps below to set letter spacing of Spinner programmatically –

  • Open res/values/dimens.xml file. Then, add below dimension in it –
    <dimen name="text_letter_spacing">1dp</dimen>
    
  • We use spinner.letterSpacing attribute to set letter spacing of Spinner as below –

    spinner.letterSpacing = resources.getDimension(R.dimen.text_letter_spacing)
    

Learn to Set Letter Spacing of Spinner Using XML Attribute

That’s end of tutorial on Spinner Programmatically in Kotlin With Example.