Kotlin - Android can we implement OnClickListener on Class?

Question

I'm starting out with Kotlin and seems that onClick does not trigger if I implement it on an Activity Class

class MainActivity : AppCompatActivity(), View.OnClickListener{

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

        tvTitle.text = "Hi There"

//        tvTitle.setOnClickListener { this } // NOT WORKING??
        tvTitle.setOnClickListener { doSomething() }
    }


    override fun onClick(v: View) {
        Log.d("click", "Hello")
    }

    fun doSomething(){
        Log.d("do", "Something")
    }
}

I'm using Android Studio 3.0 with kotlin_version of 1.1.51, thank you in advance

score 17 · Accepted Answer · answered Dec 05 '17 at 05:18

Try this

class MainActivity : AppCompatActivity(), View.OnClickListener{

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

    tvTitle.text = "Hi There"

    tvTitle.setOnClickListener(this)
   //   tvTitle.setOnClickListener { doSomething() }
}


override fun onClick(v: View) {
    Log.d("click", "Hello")
}

fun doSomething(){
    Log.d("do", "Something")
}
}

score 5 · Answer 2 · edited Jul 24 '18 at 07:56

This is my kotlin code :

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.view.View
import android.widget.LinearLayout
import android.widget.Toast

class Activity_T : AppCompatActivity(), View.OnClickListener {
    private var linear_exit: LinearLayout? = null
    private var linear_history: LinearLayout? = null
    private var linear_recipe: LinearLayout? = null

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

    private fun setOnClicks() {
        linear_exit!!.setOnClickListener(this)
        linear_history!!.setOnClickListener(this)
        linear_recipe!!.setOnClickListener(this)
    }

    private fun initView() {
        linear_exit = findViewById(R.id.linear_exit)
        linear_history = findViewById(R.id.linear_history)
        linear_recipe = findViewById(R.id.linear_recipe)
    }

    override fun onClick(v: View) {
        val item_id = v.id
        when (item_id) {
            R.id.linear_recipe -> Toast.makeText(this, "recipe", Toast.LENGTH_SHORT).show()
            R.id.linear_history -> Toast.makeText(this, "history", Toast.LENGTH_SHORT).show()

            R.id.linear_exit -> Toast.makeText(this, "exit", Toast.LENGTH_SHORT).show()
        }
    }
}

And this is part of my xml layout that had onclicks:

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_alignParentBottom="true">


        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <LinearLayout
                android:id="@+id/linear_exit"

                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_margin="10dp"
                android:layout_weight="1"
                android:background="@color/border_green"
                android:gravity="center">

                <net.kibotu.heartrateometer.utils.MyTextView
                    android:textSize="13sp"
                    android:textColor="@android:color/white"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/exit" />
            </LinearLayout>

            <LinearLayout
                android:id="@+id/linear_history"

                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_margin="10dp"
                android:layout_weight="1"
                android:background="@color/border_green"
                android:gravity="center">

                <net.kibotu.heartrateometer.utils.MyTextView
                    android:textSize="13sp"
                    android:textColor="@android:color/white"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/history" />
            </LinearLayout>

            <LinearLayout
                android:id="@+id/linear_recipe"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_margin="10dp"
                android:layout_weight="1"
                android:background="@color/border_green"

                android:gravity="center">

                <net.kibotu.heartrateometer.utils.MyTextView
                    android:textSize="13sp"
                    android:textColor="@android:color/white"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/recipe" />
            </LinearLayout>
        </LinearLayout>
    </LinearLayout>

score 0 · Answer 3 · answered Dec 05 '17 at 04:15

0

try println("Something") first.

answered Dec 05 '17 at 04:15

Maxim Firsoff

2,038
22
28

score 0 · Answer 4 · answered Jul 16 '18 at 09:19

You can try this way.

override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
         val tvTitle = findViewById<TextView>(R.id.tvTitle)
         tvTitle.setText("Hello Kotlin")

         tvTitle.setOnClickListener(object : View.OnClickListener{
                override fun onClick(v: View?) {
                    Toast.makeText(this@MainActivity,"You Clicked on " + tvTitle.text.toString(),Toast.LENGTH_SHORT).show()
                }
          })
    }

Kotlin - Android can we implement OnClickListener on Class?

4 Answers4