Why isn't setOnLongClickListner function working in Android Studio?

SumitaDas
May 11, 2023
264 views
0 votes
2 Answers

I was trying to display custom toast by on Long click of a button a default toast on click of a button but long click method is showing error line
here is the code

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        btntoste.setOnClickListener {
            Toast.makeText(this,"this is defult toaste",Toast.LENGTH_SHORT)
        }
        btntoste.setOnLongClickListener {
            Toast(this).apply {
                duration = Toast.LENGTH_LONG
                view = layoutInflater.inflate(R.layout.custom_toaste, layconstrain)
                show()

            }
        }
    }
}

also the app is crash while lunching
here is the logcat error

failed to add asset path /data/app/com.sumita.toaste-wg1Yd4-KC7e1sn36eDPchA==/base.apk
2023-05-10 11:58:44.858 18737-18737 ResourcesManager        pid-18737                            E  failed to add asset path /data/app/com.sumita.toaste-wg1Yd4-KC7e1sn36eDPchA==/base.apk
2023-05-10 11:58:44.861 18737-18737 ResourcesManager        pid-18737                            E  failed to add asset path /data/app/com.sumita.toaste-wg1Yd4-KC7e1sn36eDPchA==/base.apk
2023-05-10 11:58:45.088  2461-2501  ActivityThread          com.sumita.toaste                    E  Failed to find provider info for cn.teddymobile.free.anteater.den.provider
2023-05-10 11:58:45.229  2461-2461  AndroidRuntime          com.sumita.toaste                    E  FATAL EXCEPTION: main
                                                                                                    Process: com.sumita.toaste, PID: 2461
                                                                                                    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.sumita.toaste/com.sumita.toaste.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                                                                                                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2994)
                                                                                                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3072)
                                                                                                        at android.app.ActivityThread.-wrap11(Unknown Source:0)
                                                                                                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1766)
                                                                                                        at android.os.Handler.dispatchMessage(Handler.java:106)
                                                                                                        at android.os.Looper.loop(Looper.java:214)
                                                                                                        at android.app.ActivityThread.main(ActivityThread.java:6977)
                                                                                                        at java.lang.reflect.Method.invoke(Native Method)
                                                                                                        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:528)
                                                                                                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:910)
                                                                                                    Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                                                                                                        at com.sumita.toaste.MainActivity.onCreate(MainActivity.kt:17)
                                                                                                        at android.app.Activity.performCreate(Activity.java:7227)
                                                                                                        at android.app.Activity.performCreate(Activity.java:7218)
                                                                                                        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
                                                                                                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2947)
                                                                                                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3072) 
                                                                                                        at android.app.ActivityThread.-wrap11(Unknown Source:0) 
                                                                                                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1766) 
                                                                                                        at android.os.Handler.dispatchMessage(Handler.java:106) 
                                                                                                        at android.os.Looper.loop(Looper.java:214) 
                                                                                                        at android.app.ActivityThread.main(ActivityThread.java:6977) 
                                                                                                        at java.lang.reflect.Method.invoke(Native Method) 
                                                                                                        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:528) 
                                                                                                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:910)

activity_main.xml file

<androidx.constraintlayout.widget.ConstraintLayout 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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btntoste"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Show Toste"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.266"
        android:backgroundTint="@color/material_dynamic_neutral50"
        android:textColor="@color/white"/>
</androidx.constraintlayout.widget.ConstraintLayout>

custom toast layout

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/layconstrain"
    android:padding="16dp"
    android:background="@color/material_dynamic_neutral70">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:src="@drawable/ic_baseline_circle_notifications_24"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/txtcucont"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:text="Hay this is custom toaste"
        android:textSize="15sp"
        android:textColor="@color/purple_700"
        app:layout_constraintBottom_toBottomOf="@+id/imageView"
        app:layout_constraintStart_toEndOf="@+id/imageView"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.583" />
</androidx.constraintlayout.widget.ConstraintLayout>

here is all the file I have for this project

Answers

You need to return boolean value in setOnLongClickListener method like that. I am using viewBinding to fetch view. Try this

import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.umesh.testapp.databinding.ActivityMainBinding
import com.umesh.testapp.databinding.CustomToasteBinding


class MainActivity : AppCompatActivity() {
 lateinit var binding: ActivityMainBinding
 override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
     binding = ActivityMainBinding.inflate(layoutInflater)
     setContentView(binding.root)
     binding.btntoste.setOnClickListener {
         Toast.makeText(this,"this is defult toaste",Toast.LENGTH_SHORT)
     }
     
     binding.btntoste.setOnLongClickListener {
         val customToasteBinding = CustomToasteBinding.inflate(layoutInflater)
         Toast(applicationContext).apply {
             duration = Toast.LENGTH_LONG
             view = customToasteBinding.root
             show()
         }
         return@setOnLongClickListener true
     }
 }
}

According to the error, the btntoste variable has a null value. That’s because you haven’t assigned the btntoste variable. To solve that:

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        //Access the Button using its id
        val toastBtn = findViewById<Button>(R.id.btntoste)
 
        //Display default toast
        toastBtn.setOnClickListener {
            Toast.makeText(this,"this is defult toaste",Toast.LENGTH_SHORT)
        }

        //Display custom toast
        toastBtn.setOnLongClickListener {
            Toast(this).apply {
                duration = Toast.LENGTH_LONG
                view = layoutInflater.inflate(R.layout.custom_toaste, layconstrain)
                show()
            }

            return@setOnLongClickListener true
        }
    }
}

You also need to return a boolean value when using the setOnLongClickListener() function.

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Why isn’t setOnLongClickListner function working in Android Studio?

Answers