adding helper for recalculating percentage heights within a constraint layout

- this allows percentages to be used which make of the screen viewport rather than the accumulated scroll height

vector/src/main/java/im/vector/app/core/extensions/ConstraintLayout.kt

@@ -16,8 +16,12 @@
 
 package im.vector.app.core.extensions
 
+import android.view.View
 import androidx.constraintlayout.widget.ConstraintLayout
 import androidx.constraintlayout.widget.ConstraintSet
+import androidx.core.view.children
+import androidx.core.view.doOnLayout
+import kotlin.math.roundToInt
 
 fun ConstraintLayout.updateConstraintSet(block: (ConstraintSet) -> Unit) {
     ConstraintSet().let {
@@ -26,3 +30,16 @@ fun ConstraintLayout.updateConstraintSet(block: (ConstraintSet) -> Unit) {
         it.applyTo(this)
     }
 }
+
+fun ConstraintLayout.realignPercentagesToParent() {
+    doOnLayout {
+        val rootHeight = (parent as View).height
+        children.forEach { child ->
+            val params = child.layoutParams as ConstraintLayout.LayoutParams
+            if (params.matchConstraintPercentHeight != 1.0f) {
+                params.height = (rootHeight * params.matchConstraintPercentHeight).roundToInt()
+                child.layoutParams = params
+            }
+        }
+    }
+}