Android-app-using-Kotlin/C2/Adding-Radio-Buttons/English-timed

Time	Narration
00:01	Welcome to the Spoken Tutorial on Adding Radio buttons.
00:06	In this tutorial we will learn to Add a Radio Group and Radio buttons
00:13	And run the Kotlin App to see the output in an Android phone
00:19	To record this tutorial, I am using Ubuntu Linux 16.04 operating system
00:26	Android Studio version 3.x and Android Phone with minimum of Android OS version 4.03
00:36	To follow this tutorial, you should have basic knowledge Java programming language and Android Studio
00:46	If not, then go through the relevant tutorials on this website.
00:51	In this tutorial, we will add Radio buttons to create Male and Female options.
00:59	The label Gender will be created using TextView tool.
01:04	Let us open Android Studio.
01:07	We will be using the same project RegistrationForm which we used earlier.
01:13	In the left panel we can see the list of recently opened projects.
01:18	Or you can click on Open an existing Android Studio Project.
01:23	And then select the RegistrationForm project from the saved location.
01:27	Select the project RegistrationForm directly from here.
01:32	It will take some time to load the project. Wait until it completes loading.
01:38	Click on activity underscore first dot xml file.
01:43	We have already created the form with few tools earlier.
01:48	Now we will add some more tools.
01:52	First, let us remove the top constraint of the Click Here button and align properly.
01:58	Once done, we can add the new tools .
02:02	So, drag TextView to show the label Gender and place it below Name EditText.
02:10	Click on this TextView and change its text attribute to Gender.
02:16	Now let us align the Gender TextView as shown.
02:21	Next we need add a Radio Group to group the radio buttons.
02:26	Why we need Radio Group?
02:39	Radio group can hold the Radio Buttons.
02:33	When radio buttons are placed inside a Radio Group, the user can only select one button at one time.
02:41	We can have any number of Radio Groups as per the requirement.
02:47	In the palette search box, type radio and find the Radio Group from the list.
02:53	Here it is available under Buttons option. The option could change in the future due to version change.
03:02	Now select and drag Radio Group and place it below the Gender TextView.
03:08	Note that Radio Group is not assigned with a default unique ID.
03:14	So first, we need to give a unique ID. Otherwise, the tool is not able to attach to other tools via constraints.
03:23	In the Attributes window, type “genderRadioGroup” in ID field and press Enter.
03:31	Position it below the Gender label by aligning the top and side constraints as shown.
03:38	Let us now add Radio Button to the Radio group.
03:42	We will add two radio buttons for Gender.
03:46	Drag it to the Component Tree panel and release it on the genderRadioGroup.
03:52	Note that it should come under the hierarchy of genderRadioGroup and not under ConstraintLayout.
03:59	Now drag one more radio button and release it on the first radio button in the Component Tree.
04:06	Now select the first radio button in the Component Tree and change its text attribute to “Male”.
04:15	Likewise, change the text attribute to “Female” for the second radio button.
04:21	We had removed the top constraint of Click Here button earlier.
04:26	Now click on the top constraint of the button.
04:30	Then drag and attach to the bottom of Radio Group to place it properly.
04:36	Lastly, run the app by clicking on the Play button and check how it looks on the phone.
04:46	Next let us see about how to declare variables in Kotlin.
04:51	var x equal to 5
04:54	Here, Int data type is assigned by default to a variable x.
05:00	val x equal to 5
05:03	The value 5 is a constant when the variable is declared using ‘val’ keyword.
05:09	val xcolon Int equal to 5
05:12	Here, we are declaring a constant value 5 to the variable x of type Int.
05:20	Otherwise, we can say val x colon Int and assign the value in the next line as xequal to 5
05:30	Switch back to Android studio interface and click on FirstActivity dot kt.
05:36	Now we will write the code that will decide which radio button is selected.
05:42	First we will create a new variable to store the gender information.
05:47	Type this line of code below the code var name equal to empty string
05:54	In setOnClickListener function, after the Toast method, write the below code.
06:00	This function returns the id of the Radio Button which is selected from the Radio Group.
06:06	The Id is stored in the variable genderId.
06:10	This function returns minus 1 when no radio button is selected.
06:15	The Radio Button value is stored in a variable selected underscore gender by the method findViewById.
06:23	findViewById method returns the view of which ID is passed as argument.
06:29	This line extracts the text of the selected radio button and stores it in the gender variable.
06:36	Now we have a new data gender, which we can pass onto the SecondActivity.
06:42	Type this code below the previous putExtra() method in the intent method.
06:48	This new data can now be accessed inside SecondActivity dot kt
06:54	Click on activity underscore second dot xml.
06:59	Let us resize the TextView to add the gender information.
07:04	Now go to SecondActivity.kt file.
07;08	Add a new variable say obtainedGender as shown.
07:13	We need to extract the new data of gender, so we will write the code as below.
07:19	This will store the gender data from FirstActivity in obtainedGender variable.
07:25	Edit the code of TextView to add the gender information like this.
07:30	The radio button code is ready to run.
07:33	Click on the Play button to run the Kotlin app.
07:38	Launch the app in the phone.
07:41	Enter your name and select any one of the gender radio buttons.
07:47	Click on the Click Here button.
07:50	A new window opens with the output as shown.
07:54	With this, we come to the end of this tutorial. Let us summarize.
08:00	In this tutorial we learnt to Add Radio Groups and Radio Buttons
08:06	Run the Kotlin app to see the output in an Android phone
08:11	As an assignment do the following.
08:14	Add one more radio button to the Radio Group and change the text attribute as “Others”.
08:21	Run the Kotlin app to check the output.
08:25	The video at the following link summarises the Spoken Tutorial project. Please download and watch it
08:33	The Spoken Tutorial Project Team conducts workshops and gives certificates. For more details, please write to us.
08:43	Please post your timed queries in this forum.
08:47	Spoken Tutorial project is funded by NMEICT, MHRD, Government of India.
08:54	More information on this mission is available at this link.
08:59	The Android app and the script for this tutorial was contributed by Abhishek Shah.
09:05	And this is Nirmala Venkat along with the Spoken Tutorial team from IIT Bombay, signing off. Thanks for watching.

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