CODEWITHSUNDEEP
androidkotlinkotlin-android-extensions
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Reputation: 3

Accessing EditText ID data returns Null

I'm new to Android Kotlin and I can't access the value I inputted on xml for input_mtk ID, which always returns null on Kotlin file. Here's my code

XML file

<TextView
        android:id="@+id/matematika"
        android:layout_width="wrap_content"
        android:layout_height="19dp"
        android:layout_marginStart="56dp"
        android:layout_marginTop="20dp"
        android:gravity="center_horizontal|top"
        android:text="@string/matematika"
        android:textAppearance="@style/string_form"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/input_bahasa_inggris" />

    <EditText
        android:id="@+id/input_mtk"
        style="@style/shape2"
        android:layout_marginStart="56dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="230dp"
        android:inputType="numberDecimal"
        android:maxLength="5"
        android:textAlignment="center"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/matematika" />

Kotlin file

class ResultFragment : Fragment() {

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {

        return inflater.inflate(R.layout.fragment_result, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        getData()
    }

    fun getData() {
        var Mat = input_mtk.text.toString()
        Log.e("test", Mat)
    }
}

It shows this error

java.lang.NullPointerException: input_mtk must not be null
        at com.xx.xx.ResultFragment.getData(ResultFragment.kt:38)
        at com.xx.xx.ResultFragment.onViewCreated(ResultFragment.kt:33)

if I change var Mat = input_mtk.text.toString() to var Mat = input_mtk?.text.toString()

shows clearly that input_mtk id returns null 2021-08-29 16:49:22.158 15887-15887/com.xx.xx E/test: null

Upvotes: 0

Views: 443

Answers (3)

vivek.kartha
vivek.kartha

Reputation: 318

input_mtk.text can be null within onViewCreated() if the Kotlin synthetic imports or View bindings are not done correctly. Also, you probably would not have entered anything in the EditText by the time onViewCreated() has finished execution

Put it inside a button's click listener:

<Button
        android:id="@+id/my_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

And then in your Kotlin class, access it:

var input = ""
my_button.setOnClickListener {
 input = input_mtk.text.toString()
}

Here input will hold the string from your EditText

Note: I am assuming you are using Kotlin synthetics. If yes, it is recommended to migrate to View Bindings - https://developer.android.com/topic/libraries/view-binding/migration

Upvotes: 1

Jalalkun
Jalalkun

Reputation: 181

if you use viewBinding you can do like this

first use viewBinding

private lateinit var binding: FragmentResultBinding
    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        binding = FragmentResultBinding.inflate(inflater)
        return binding.root
    }

and change function getData like this

private fun getData(){
        val input = binding.inputMtk.text.toString()
        Log.e("FragmentResult", "getData: input: $input" )
    }

Upvotes: 0

AShX
AShX

Reputation: 412

I do not really understand, what are you trying to do.

EditText is a view where the user inputs some data. When you create your app and run it, it has a null value aka "there is no content".

You can manually add text in your xml,if you want:

  <EditText
        android:id="@+id/input_mtk"
        android:text="sometext"
        ... />

But its make zero sense since this view is designed to give user opportunity to input own data, and should be empty in most of the cases. Use TextView instead

If you want to read inputed data, you can use button:

yourButton.setOnClickListener { input_mtk?.text.toString() }

Upvotes: 0

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