Ensure the invisible buttons have the correct size.

features/verifysession/impl/src/main/kotlin/io/element/android/features/verifysession/impl/incoming/IncomingVerificationView.kt

@@ -10,9 +10,7 @@ package io.element.android.features.verifysession.impl.incoming
 import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
-import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.runtime.Composable
@@ -35,6 +33,7 @@ import io.element.android.libraries.designsystem.components.PageTitle
 import io.element.android.libraries.designsystem.preview.ElementPreview
 import io.element.android.libraries.designsystem.preview.PreviewsDayNight
 import io.element.android.libraries.designsystem.theme.components.Button
+import io.element.android.libraries.designsystem.theme.components.InvisibleButton
 import io.element.android.libraries.designsystem.theme.components.Text
 import io.element.android.libraries.designsystem.theme.components.TextButton
 import io.element.android.libraries.designsystem.theme.components.TopAppBar
@@ -166,8 +165,7 @@ private fun IncomingVerificationBottomMenu(
                         enabled = false,
                         showProgress = true,
                     )
-                    // Placeholder so the 1st button keeps its vertical position
-                    Spacer(modifier = Modifier.height(40.dp))
+                    InvisibleButton()
                 }
             } else {
                 VerificationBottomMenu {
@@ -194,8 +192,7 @@ private fun IncomingVerificationBottomMenu(
                         enabled = false,
                         showProgress = true,
                     )
-                    // Placeholder so the 1st button keeps its vertical position
-                    Spacer(modifier = Modifier.height(40.dp))
+                    InvisibleButton()
                 }
             } else {
                 VerificationBottomMenu {

features/verifysession/impl/src/main/kotlin/io/element/android/features/verifysession/impl/outgoing/VerifySelfSessionView.kt

@@ -12,10 +12,8 @@ import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.runtime.Composable
@@ -44,6 +42,7 @@ import io.element.android.libraries.designsystem.preview.ElementPreview
 import io.element.android.libraries.designsystem.preview.PreviewsDayNight
 import io.element.android.libraries.designsystem.theme.components.Button
 import io.element.android.libraries.designsystem.theme.components.CircularProgressIndicator
+import io.element.android.libraries.designsystem.theme.components.InvisibleButton
 import io.element.android.libraries.designsystem.theme.components.OutlinedButton
 import io.element.android.libraries.designsystem.theme.components.Text
 import io.element.android.libraries.designsystem.theme.components.TextButton
@@ -282,8 +281,7 @@ private fun VerifySelfSessionBottomMenu(
                     text = stringResource(CommonStrings.action_start_verification),
                     onClick = { eventSink(VerifySelfSessionViewEvents.RequestVerification) },
                 )
-                // Placeholder so the 1st button keeps its vertical position
-                Spacer(modifier = Modifier.height(40.dp))
+                InvisibleButton()
             }
         }
         is Step.Canceled -> {
@@ -293,8 +291,7 @@ private fun VerifySelfSessionBottomMenu(
                     text = stringResource(CommonStrings.action_done),
                     onClick = onCancelClick,
                 )
-                // Placeholder so the 1st button keeps its vertical position
-                Spacer(modifier = Modifier.height(40.dp))
+                InvisibleButton()
             }
         }
         is Step.Ready -> {
@@ -320,8 +317,7 @@ private fun VerifySelfSessionBottomMenu(
                     showProgress = true,
                     enabled = false,
                 )
-                // Placeholder so the 1st button keeps its vertical position
-                Spacer(modifier = Modifier.height(40.dp))
+                InvisibleButton()
             }
         }
         is Step.Verifying -> {
@@ -343,8 +339,7 @@ private fun VerifySelfSessionBottomMenu(
                     },
                 )
                 if (isVerifying) {
-                    // Placeholder so the 1st button keeps its vertical position
-                    Spacer(modifier = Modifier.height(40.dp))
+                    InvisibleButton()
                 } else {
                     TextButton(
                         modifier = Modifier.fillMaxWidth(),
@@ -361,8 +356,7 @@ private fun VerifySelfSessionBottomMenu(
                     text = stringResource(CommonStrings.action_continue),
                     onClick = onContinueClick,
                 )
-                // Placeholder so the 1st button keeps its vertical position
-                Spacer(modifier = Modifier.height(48.dp))
+                InvisibleButton()
             }
         }
         is Step.Skipped -> return

libraries/designsystem/src/main/kotlin/io/element/android/libraries/designsystem/theme/components/Button.kt

@@ -17,6 +17,7 @@ import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.heightIn
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
@@ -118,6 +119,14 @@ fun TextButton(
     leadingIcon = leadingIcon
 )
 
+@Composable
+fun InvisibleButton(
+    modifier: Modifier = Modifier,
+    size: ButtonSize = ButtonSize.Large,
+) {
+    Spacer(modifier = modifier.height(size.toMinHeight()))
+}
+
 @Composable
 private fun ButtonInternal(
     text: String,
@@ -131,14 +140,7 @@ private fun ButtonInternal(
     showProgress: Boolean = false,
     leadingIcon: IconSource? = null,
 ) {
-    val minHeight = when (size) {
-        ButtonSize.Small -> 32.dp
-        ButtonSize.Medium,
-        ButtonSize.MediumLowPadding -> 40.dp
-        ButtonSize.Large,
-        ButtonSize.LargeLowPadding -> 48.dp
-    }
-
+    val minHeight = size.toMinHeight()
     val hasStartDrawable = showProgress || leadingIcon != null
 
     val contentPadding = when (size) {
@@ -253,6 +255,14 @@ private fun ButtonInternal(
     }
 }
 
+private fun ButtonSize.toMinHeight() = when (this) {
+    ButtonSize.Small -> 32.dp
+    ButtonSize.Medium,
+    ButtonSize.MediumLowPadding -> 40.dp
+    ButtonSize.Large,
+    ButtonSize.LargeLowPadding -> 48.dp
+}
+
 @Immutable
 sealed interface IconSource {
     val contentDescription: String?