Attempt to invoke virtual method on a null object reference -> resolve? - kotlin

Question

I try to do a button for switch from a main activity to an other, but when I try to run the app, it close itself immediatly after click on the app. I find in the command that message of error :
Unable to start activity ComponentInfo{fr.amseu.mystretching/fr.amseu.mystretching.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageButton.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
My code in the MainActivity is this one :
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val button = findViewById<ImageButton>(R.id.imageButton)
button.setOnClickListener {
val intent = Intent(this, SecondActivity::class.java)
startActivity(intent);}
That is my Main Activity :
<?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"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/item_main"
android:background="#color/light_red">
<androidx.cardview.widget.CardView
android:id="#+id/cardView"
android:layout_width="100dp"
android:layout_height="120dp"
app:cardCornerRadius="8dp"
app:cardElevation="5dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<ImageButton
android:id="#+id/imageButton"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="centerCrop"
android:src="#drawable/lower_legs"
android:contentDescription="#string/home_page_first_button" />
</androidx.cardview.widget.CardView>
<View
android:id="#+id/view_separation"
android:layout_width="match_parent"
android:visibility="invisible"
android:layout_height="1dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
<TextView
android:id="#+id/name_item"
style="#style/SubTitleTextStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="#dimen/default_margin"
android:text="#string/home_page_first_button"
app:layout_constraintBottom_toTopOf="#+id/view_separation"
app:layout_constraintStart_toEndOf="#+id/cardView"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/description_item"
style="#style/DefaultTextStyle"
android:layout_width="250dp"
android:layout_height="wrap_content"
android:text="#string/home_page_description_1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="#+id/name_item"
app:layout_constraintTop_toBottomOf="#+id/view_separation" />
</androidx.constraintlayout.widget.ConstraintLayout>
And for my recycler view, I take this model in my page and the following item are siblings but I change the image and texts, with an adapter, HomeFragment...
Can someone help me please ?
(It is my first app)
Thanks a lot !