How to properly make a view inside ConstraintLayout take percent height of visible area when root view is a ScrollView

Question

I have this hierarchy of views

ScrollView
        ConstraintLayout
            ImageView

            LinearLayout
                TextView
                TextView
                TextView
                ...

What I want to achieve is that the ImageView takes like 65% percent of the visible screen vertically... but since the root view is a ScrollView, the ImageView takes 65% of the scrollable area... I want the ImageView takes 65% of visible area.

What would be the best way to proced in order to get something like this?

Source code:

<ScrollView
  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:fillViewport="true"
  tools:context=".MainActivity">

  <android.support.constraint.ConstraintLayout
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
      android:id="@+id/header"
      android:layout_width="match_parent"
      android:layout_height="0dp"
      android:scaleType="centerCrop"
      android:src="@drawable/rain"
      app:layout_constraintHeight_percent=".65"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent"
      app:layout_constraintTop_toTopOf="parent"/>

    <LinearLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="vertical"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent"
      app:layout_constraintTop_toBottomOf="@id/header">

      <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="AAAAAA"
        android:textSize="50dp"/>

      <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="BBBB"
        android:textSize="50dp"/>

      <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="CCCCC"
        android:textSize="50dp"/>

      <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="DDDDD"
        android:textSize="50dp"/>



    </LinearLayout>
  </android.support.constraint.ConstraintLayout>

</ScrollView>

Thanks in advance

Answer 1

You can't set height as percentage when inside scrollview.

I have suggest you use Aspect ratio to match your requirements.

In your imageview set height 0dp & set dimension ratio for height.

android:layout_height="0dp"
app:layout_constraintDimensionRatio="H,1:1" //change ratio as per your image ratio