Android Studio guideline header percentage not working

Question

<?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="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.constraintlayout.widget.Guideline
        android:id="@+id/guideline4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_begin="323dp" />
</androidx.constraintlayout.widget.ConstraintL

I want to use a guideline in Android Studio in a percentage form. but when I click on the header of the vertical guideline to change it to a percentage, it won't change, but surprisingly the horizontal one changes easily to percentage mode?! why does it happen?

Answer 1

• If you want to set percent of guideline , you should use app:layout_constraintGuide_percent
• orientaion means guideline's orientaion
  • you can think guideline is like a (Invisible) View
  • android:orientation="horizontal" -> guideline is horizontal line -> you can set other view vertically by this
  • vice versa

for example

<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">

    <androidx.constraintlayout.widget.Guideline
        android:id="@+id/vertical_guideline"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.48" />

    <androidx.constraintlayout.widget.Guideline
        android:id="@+id/horizontal_guideline"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.73" />
</androidx.constraintlayout.widget.ConstraintLayout>