DataBinding-Sample

📢 Kotlin Synthetics

plugins{

id 'kotlin-android-extensions'

}

You should add this in build.gradle and then you can use kotlin-synthetic

textView.text = "Sumeyra"

Dipnot: kotlin synthetic will be removed in Kotlin 1.8, which is expected to be released by the end of 2022.

📢FindViewByID

For using FindViewById you don't need to add anything in gradle file. You can also use it in Java.

📍In Activity

    val textName:TextView = findViewById(R.id.textView)
    val textPopulation:TextView = findViewById(R.id.textView2)
    val textFamous:TextView = findViewById(R.id.textView3)
    val buttonClick: Button = findViewById(R.id.btnClick )

    val izmir = City("İzmir",3000,"Boyoz")

    textName.text = izmir.name
    textPopulation.text = "Nüfusu: ${izmir.population}"
    textFamous.text =izmir.famousWith

    buttonClick.setOnClickListener {
        Toast.makeText(applicationContext,"Button Cliked",Toast.LENGTH_SHORT).show()
     }

📍 In Fragment

    private lateinit var  buton: Button
    private lateinit var  textName: TextView
    private lateinit var  textPopulation: TextView
    private lateinit var  textFamous: TextView

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        val city = City("İzmir",3000,"Boyoz")
        buton = view.findViewById(R.id.btnClick)
        textName = view.findViewById(R.id.textView)
        textPopulation = view.findViewById(R.id.textView3)
        textFamous = view.findViewById(R.id.textView2)


        textName.text = city.name
        textPopulation.text=city.population.toString()
        textFamous.text= city.famousWith

        buton.setOnClickListener {
            Toast.makeText(activity,"Button Cliked",Toast.LENGTH_SHORT).show()

        }

📢 DataBinding

For dataBinding, you should add this and kotlin-kapt plugin in build.gradle

buildFeatures {
        dataBinding true
    }

if you want to use dataBinding, you have to open layout tag in xml.

<layout
    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">

if you want to use data directly in xml, databinding make you use that like this

 <data>
        <variable
            name="city"
            type="com.sum.databinding.City"
            />

    </data>

In TextView you should do like this android:text="@{city.name}"

📍In Activity

You should initialize it first private lateinit var binding: ActivityMainBinding

    binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
    binding.city =City("İzmir",300,"Boyoz")

📍In Fragment

    private var _binding: FragmentBlankBinding? = null
    private val binding get() = _binding!!

 override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?,
    ): View? {
        // Inflate the layout for this fragment
        _binding = DataBindingUtil.inflate(inflater, R.layout.fragment_blank, container, false)
        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        binding.city =City("İzmir",300,"Boyoz")
        binding.btnClick.setOnClickListener {
            Toast.makeText(activity, "Button cliked",Toast.LENGTH_SHORT).show()
        }
    }

📢ViewBinding

📍 In Activity

buildFeatures {
        viewBinding true
    }

You should this part in build.gradle and then you can use it everywhere. Of Course you should initialize it first. private lateinit var binding: ActivityMainBinding

    binding = ActivityMainBinding.inflate(layoutInflater)
    val view = binding.root
    setContentView(view)

    val izmir = City("İzmir",3000,"Boyoz")

    binding.textView.text = izmir.name
    binding.textView2.text =izmir.population.toString()
    binding.textView3.text = izmir.famousWith

📍 In Fragment

   private var _binding: FragmentBlankBinding? = null
   private val binding get() = _binding!!

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?,
    ): View? {
       _binding = FragmentBlankBinding.inflate(inflater, container, false)
       val view = binding.root
       return view
       
   }

   override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
       super.onViewCreated(view, savedInstanceState)
       val city =City("İzmir",3000,"Boyoz")
       binding.textView.text = city.name
       binding.textView2.text = city.population.toString()
       binding.textView3.text = city.famousWith

       binding.btnClick.setOnClickListener {
           Toast.makeText(activity, "Button cliked", Toast.LENGTH_SHORT).show()
       }

In Google I/O'19, Google said us you should viewBinding. If you want to watch it. Please click

In below, you will see my viewBinding screenshot. I did it every part(findViewById, viewBinding, dataBinding). If you examine this codes. You will get it better.