problem in mainactivity.kt, the app crashes in landscape view and works in regular view, there's an onClickListener which is causing the error

Question

i'm using activity_main in regular & landscape view, i added a button in regular view, it worked, after placing toast message in regular view the app is crashing in landscapeview. how can i solve the issue. I'm newbie.strong text

activity_main

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/btn1"
        android:layout_alignStart="@+id/btn1"
        android:layout_alignEnd="@+id/btn1"
        android:layout_centerVertical="true"
        android:layout_marginStart="0dp"
        android:layout_marginEnd="0dp"
        android:text="Hello World!" />

    <Button
        android:id="@+id/btn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Nuke"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:textStyle="bold"/>


</RelativeLayout>

activity_main(land)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    android:backgroundTint="@color/black"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:backgroundTint="@color/black"
        android:text="Landscape is not supported\nPlease rotate your device."
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"/>
</RelativeLayout>

logcat RuntimeException

022-05-09 12:03:45.391 23622-23622/com.fox.nolandscapesupport E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.fox.nolandscapesupport, PID: 23622
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.fox.nolandscapesupport/com.fox.nolandscapesupport.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2914)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3049)
        at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:4785)
        at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4694)
        at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1809)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6692)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at com.fox.nolandscapesupport.MainActivity.onCreate(MainActivity.kt:14)
        at android.app.Activity.performCreate(Activity.java:7140)
        at android.app.Activity.performCreate(Activity.java:7131)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1272)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2894)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3049) 
        at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:4785) 
        at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4694) 
        at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1809) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6692) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

Here everything from android studio. please someone solve my issue. I'm a new beginner in android studio.

Please trim your code to make it easier to find your problem. Follow these guidelines to create a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example). — Community, May 09 '22 at 11:49
show your MainActivity.kt file and not just the layout, It will be easier to solve your problem !! — Rahul Pandey, May 11 '22 at 06:09

problem in mainactivity.kt, the app crashes in landscape view and works in regular view, there's an onClickListener which is causing the error

0 Answers0