ConstraintLayout - center TextView in the root but don't override Button

To fix this issue I followed this tutorial, for now it's working nice, but i only have a problem, i need to center vertically the "Title" textview, when "Detail" textview text it's null or empty, something like this. I tried this (http://www.curious-creature.org/2009/02/22/android-layout-tricks-1/), and it works, but the problem it's that if i use setVisibility(View.GONE), all the details from all the items, dissapear, and just title get centered., any help appreciated, thanks , Remember to setVisible(View.VISIBLE) when you are recycling a view.

String detail = "some detail....";
detailTextView.setVisible(detail == null ? View.GONE : View.VISIBLE);

help you fix your problem I'm beginner in android,and want to write xml file show two button center of screen horizontally,write this code: , Try this code. It will give desired layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<TextView
    android:id="@+id/TextView01"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@+id/TextView01" />


<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1"
    android:gravity="center"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:orientation="horizontal">

        <Button
            android:id="@+id/allow"
            android:gravity="center"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Allow" />

        <Button
            android:id="@+id/deny"
            android:layout_width="wrap_content"
            android:gravity="center"
            android:layout_height="wrap_content"
            android:text="Deny" />
    </LinearLayout>


</LinearLayout>
</LinearLayout>

I hope this helps you . You could simply set a text to the button when it is clicked instead of using a TextView.
In your onClick() method write:

btnScale.setText("Appear");

android:textColor="@android:color/white"

I think the issue was by ths following , Your layout is fine, Just set android:layout_width="0dp" to your textView

it helps some times This is because both your ConstraintLayout and TextView is sharing the same id text in your layout XML file. As a result, when you try to refer the TextView in your Java code via R.id.text, it links to your ConstraintLayout instead which causes the crash.
Change the id of your ConstraintLayout to something else (like mainlayout).

<?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:id="@+id/mainlayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">

<TextView
    android:id="@+id/text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.32" />

<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"

    android:layout_height="wrap_content"
    android:layout_marginStart="8dp"
    android:layout_marginLeft="8dp"

    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginRight="8dp"
    android:onClick="onButtonClick"
    android:text="click me"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/text" />

<EditText
    android:id="@+id/nameEditText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginStart="8dp"
    android:layout_marginLeft="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginRight="8dp"
    android:layout_marginBottom="8dp"
    android:ems="10"
    android:inputType="textPersonName"
    android:text="Name"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/button" />