Added snippets for SupportingPaneScaffold (#260)

* Added snippets for SupportingPaneScaffold
* Apply Spotless
* Update compose/snippets/src/main/java/com/example/compose/snippets/adaptivelayouts/SampleSupportingPaneScaffold.kt

Author: IanGClifton

compose/snippets/src/main/java/com/example/compose/snippets/adaptivelayouts/SampleSupportingPaneScaffold.kt

@@ -0,0 +1,147 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+@file:OptIn(ExperimentalMaterial3AdaptiveApi::class)
+
+package com.example.compose.snippets.adaptivelayouts
+
+import androidx.activity.compose.BackHandler
+import androidx.compose.foundation.layout.safeContentPadding
+import androidx.compose.foundation.layout.wrapContentSize
+import androidx.compose.material3.Button
+import androidx.compose.material3.Text
+import androidx.compose.material3.adaptive.ExperimentalMaterial3AdaptiveApi
+import androidx.compose.material3.adaptive.layout.AnimatedPane
+import androidx.compose.material3.adaptive.layout.PaneAdaptedValue
+import androidx.compose.material3.adaptive.layout.SupportingPaneScaffold
+import androidx.compose.material3.adaptive.layout.SupportingPaneScaffoldRole
+import androidx.compose.material3.adaptive.layout.ThreePaneScaffoldRole
+import androidx.compose.material3.adaptive.layout.ThreePaneScaffoldScope
+import androidx.compose.material3.adaptive.navigation.rememberSupportingPaneScaffoldNavigator
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+
+@Composable
+fun SampleSupportingPaneScaffoldParts() {
+    // [START android_compose_adaptivelayouts_sample_supporting_pane_scaffold_nav_and_back]
+    val navigator = rememberSupportingPaneScaffoldNavigator()
+
+    BackHandler(navigator.canNavigateBack()) {
+        navigator.navigateBack()
+    }
+    // [END android_compose_adaptivelayouts_sample_supporting_pane_scaffold_nav_and_back]
+
+    // [START android_compose_adaptivelayouts_sample_supporting_pane_scaffold_params]
+    SupportingPaneScaffold(
+        directive = navigator.scaffoldDirective,
+        value = navigator.scaffoldValue,
+        mainPane = { /*...*/ },
+        supportingPane = { /*...*/ },
+    )
+    // [END android_compose_adaptivelayouts_sample_supporting_pane_scaffold_params]
+}
+
+@Composable
+fun SampleSupportingPaneScaffoldFull() {
+    // [START android_compose_adaptivelayouts_sample_supporting_pane_scaffold_full]
+    val navigator = rememberSupportingPaneScaffoldNavigator()
+
+    BackHandler(navigator.canNavigateBack()) {
+        navigator.navigateBack()
+    }
+
+    SupportingPaneScaffold(
+        directive = navigator.scaffoldDirective,
+        value = navigator.scaffoldValue,
+        mainPane = {
+            AnimatedPane(modifier = Modifier.safeContentPadding()) {
+                // Main pane content
+                if (navigator.scaffoldValue[SupportingPaneScaffoldRole.Supporting] == PaneAdaptedValue.Hidden) {
+                    Button(
+                        modifier = Modifier.wrapContentSize(),
+                        onClick = {
+                            navigator.navigateTo(SupportingPaneScaffoldRole.Supporting)
+                        }
+                    ) {
+                        Text("Show supporting pane")
+                    }
+                } else {
+                    Text("Supporting pane is shown")
+                }
+            }
+        },
+        supportingPane = {
+            AnimatedPane(modifier = Modifier.safeContentPadding()) {
+                // Supporting pane content
+                Text("Supporting pane")
+            }
+        },
+    )
+    // [END android_compose_adaptivelayouts_sample_supporting_pane_scaffold_full]
+}
+
+// [START android_compose_adaptivelayouts_sample_supporting_pane_scaffold_extracted_panes]
+@Composable
+fun ThreePaneScaffoldScope.MainPane(
+    shouldShowSupportingPaneButton: Boolean,
+    onNavigateToSupportingPane: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    AnimatedPane(modifier = modifier.safeContentPadding()) {
+        // Main pane content
+        if (shouldShowSupportingPaneButton) {
+            Button(onClick = onNavigateToSupportingPane) {
+                Text("Show supporting pane")
+            }
+        } else {
+            Text("Supporting pane is shown")
+        }
+    }
+}
+
+@Composable
+fun ThreePaneScaffoldScope.SupportingPane(
+    modifier: Modifier = Modifier,
+) {
+    AnimatedPane(modifier = modifier.safeContentPadding()) {
+        // Supporting pane content
+        Text("This is the supporting pane")
+    }
+}
+// [END android_compose_adaptivelayouts_sample_supporting_pane_scaffold_extracted_panes]
+
+@Composable
+fun SampleSupportingPaneScaffoldSimplified() {
+// [START android_compose_adaptivelayouts_sample_supporting_pane_scaffold_simplified]
+    val navigator = rememberSupportingPaneScaffoldNavigator()
+
+    BackHandler(navigator.canNavigateBack()) {
+        navigator.navigateBack()
+    }
+
+    SupportingPaneScaffold(
+        directive = navigator.scaffoldDirective,
+        value = navigator.scaffoldValue,
+        mainPane = {
+            MainPane(
+                shouldShowSupportingPaneButton = navigator.scaffoldValue.secondary == PaneAdaptedValue.Hidden,
+                onNavigateToSupportingPane = { navigator.navigateTo(ThreePaneScaffoldRole.Secondary) }
+            )
+        },
+        supportingPane = { SupportingPane() },
+    )
+// [END android_compose_adaptivelayouts_sample_supporting_pane_scaffold_simplified]
+}