Refine edge-to-edge handling across screens

app/src/main/java/com/d4rk/androidtutorials/java/utils/EdgeToEdgeDelegate.java

@@ -5,13 +5,21 @@
 import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.appcompat.widget.Toolbar;
 import androidx.core.graphics.Insets;
+import androidx.core.view.MarginLayoutParamsCompat;
 import androidx.core.view.ViewCompat;
 import androidx.core.view.ViewGroupCompat;
 import androidx.core.view.WindowCompat;
 import androidx.core.view.WindowInsetsCompat;
 
 import com.d4rk.androidtutorials.java.R;
+import com.google.android.material.appbar.AppBarLayout;
+import com.google.android.material.bottomappbar.BottomAppBar;
+import com.google.android.material.floatingactionbutton.ExtendedFloatingActionButton;
+import com.google.android.material.floatingactionbutton.FloatingActionButton;
+import com.google.android.material.navigation.NavigationBarView;
 
 public final class EdgeToEdgeDelegate {
 
@@ -21,37 +29,133 @@ private EdgeToEdgeDelegate() {
 
     public static void apply(Activity activity, View view) {
         enableEdgeToEdge(activity);
-        applyInsetsAsPadding(
+        applyInsetsInternal(
                 view,
-                WindowInsetsCompat.Type.systemBars() | WindowInsetsCompat.Type.displayCutout(),
-                true,
-                true
+                null,
+                WindowInsetsCompat.Type.systemBars() | WindowInsetsCompat.Type.displayCutout()
         );
     }
 
     public static void applyBottomBar(Activity activity, View container, View bottomNavigationView) {
         enableEdgeToEdge(activity);
-        applyInsetsAsPadding(
+        applyInsetsInternal(
                 container,
-                WindowInsetsCompat.Type.systemBars() | WindowInsetsCompat.Type.displayCutout(),
-                true,
-                false
-        );
-        applyInsetsAsPadding(
                 bottomNavigationView,
-                WindowInsetsCompat.Type.systemBars() | WindowInsetsCompat.Type.displayCutout(),
-                false,
-                true
+                WindowInsetsCompat.Type.systemBars() | WindowInsetsCompat.Type.displayCutout()
         );
     }
 
+    private static void applyInsetsInternal(View root, @Nullable View explicitBottomBar, int insetTypes) {
+        if (root == null) {
+            return;
+        }
+
+        View topBar = null;
+        View bottomBar = explicitBottomBar;
+        if (root instanceof ViewGroup viewGroup) {
+            topBar = findTopBar(viewGroup);
+            if (bottomBar == null) {
+                bottomBar = findBottomBar(viewGroup);
+            }
+            applyInsetsToFloatingButtons(viewGroup, insetTypes);
+        }
+
+        if (topBar != null && topBar != root) {
+            applyInsetsAsPadding(topBar, insetTypes, true, false);
+        }
+        if (bottomBar != null && bottomBar != root) {
+            applyInsetsAsPadding(bottomBar, insetTypes, false, true);
+        }
+
+        boolean applyTop = topBar == null || topBar == root;
+        boolean applyBottom = bottomBar == null || bottomBar == root;
+        applyInsetsAsPadding(root, insetTypes, applyTop, applyBottom);
+    }
+
     private static void enableEdgeToEdge(Activity activity) {
         if (activity == null) {
             return;
         }
         WindowCompat.enableEdgeToEdge(activity.getWindow());
     }
 
+    @Nullable
+    private static View findTopBar(View view) {
+        if (!isVisible(view)) {
+            return null;
+        }
+        if (isTopBar(view)) {
+            return view;
+        }
+        if (view instanceof ViewGroup viewGroup) {
+            for (int i = 0; i < viewGroup.getChildCount(); i++) {
+                View child = viewGroup.getChildAt(i);
+                View topBar = findTopBar(child);
+                if (topBar != null) {
+                    return topBar;
+                }
+            }
+        }
+        return null;
+    }
+
+    @Nullable
+    private static View findBottomBar(View view) {
+        if (!isVisible(view)) {
+            return null;
+        }
+        if (isBottomBar(view)) {
+            return view;
+        }
+        if (view instanceof ViewGroup viewGroup) {
+            for (int i = 0; i < viewGroup.getChildCount(); i++) {
+                View child = viewGroup.getChildAt(i);
+                View bottomBar = findBottomBar(child);
+                if (bottomBar != null) {
+                    return bottomBar;
+                }
+            }
+        }
+        return null;
+    }
+
+    private static void applyInsetsToFloatingButtons(View view, int insetTypes) {
+        if (!isVisible(view)) {
+            return;
+        }
+        if (view instanceof ExtendedFloatingActionButton || view instanceof FloatingActionButton) {
+            applyInsetsAsMargin(view, insetTypes, false, true);
+            return;
+        }
+        if (view instanceof ViewGroup viewGroup) {
+            for (int i = 0; i < viewGroup.getChildCount(); i++) {
+                applyInsetsToFloatingButtons(viewGroup.getChildAt(i), insetTypes);
+            }
+        }
+    }
+
+    private static boolean isTopBar(View view) {
+        int id = view.getId();
+        return view instanceof AppBarLayout
+                || view instanceof Toolbar
+                || id == R.id.app_bar_layout
+                || id == R.id.toolbar
+                || id == R.id.top_app_bar;
+    }
+
+    private static boolean isBottomBar(View view) {
+        int id = view.getId();
+        return view instanceof NavigationBarView
+                || view instanceof BottomAppBar
+                || id == R.id.nav_view
+                || id == R.id.bottom_nav
+                || id == R.id.bottomBar;
+    }
+
+    private static boolean isVisible(View view) {
+        return view.getVisibility() == View.VISIBLE;
+    }
+
     private static void applyInsetsAsPadding(View view, int insetTypes,
                                              boolean applyTop,
                                              boolean applyBottom) {
@@ -95,6 +199,43 @@ private static void applyInsetsAsPadding(View view, int insetTypes,
         requestApplyInsetsWhenAttached(view);
     }
 
+    private static void applyInsetsAsMargin(View view, int insetTypes,
+                                            boolean applyTop,
+                                            boolean applyBottom) {
+        if (view == null) {
+            return;
+        }
+        ViewGroup.LayoutParams layoutParams = view.getLayoutParams();
+        if (!(layoutParams instanceof ViewGroup.MarginLayoutParams marginLayoutParams)) {
+            return;
+        }
+
+        InsetsMargin baseMargin = (InsetsMargin) view.getTag(R.id.tag_edge_to_edge_margin);
+        if (baseMargin == null) {
+            baseMargin = new InsetsMargin(
+                    MarginLayoutParamsCompat.getMarginStart(marginLayoutParams),
+                    marginLayoutParams.topMargin,
+                    MarginLayoutParamsCompat.getMarginEnd(marginLayoutParams),
+                    marginLayoutParams.bottomMargin
+            );
+            view.setTag(R.id.tag_edge_to_edge_margin, baseMargin);
+        }
+
+        InsetsMargin margin = baseMargin;
+        ViewCompat.setOnApplyWindowInsetsListener(view, (v, windowInsets) -> {
+            Insets insets = windowInsets.getInsets(insetTypes);
+            ViewGroup.MarginLayoutParams lp = (ViewGroup.MarginLayoutParams) v.getLayoutParams();
+            MarginLayoutParamsCompat.setMarginStart(lp, margin.start + insets.left);
+            lp.topMargin = margin.top + (applyTop ? insets.top : 0);
+            MarginLayoutParamsCompat.setMarginEnd(lp, margin.end + insets.right);
+            lp.bottomMargin = margin.bottom + (applyBottom ? insets.bottom : 0);
+            v.setLayoutParams(lp);
+            return windowInsets;
+        });
+
+        requestApplyInsetsWhenAttached(view);
+    }
+
     private static void requestApplyInsetsWhenAttached(@NonNull View view) {
         if (ViewCompat.isAttachedToWindow(view)) { // FIXME: 'isAttachedToWindow([email protected] View)' is deprecated
             ViewCompat.requestApplyInsets(view);
@@ -116,4 +257,7 @@ public void onViewDetachedFromWindow(@NonNull View v) {
 
     private record InsetsPadding(int start, int top, int end, int bottom) {
     }
+
+    private record InsetsMargin(int start, int top, int end, int bottom) {
+    }
 }

app/src/main/res/layout/activity_help.xml

@@ -4,9 +4,8 @@
     android:id="@+id/container"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:layout_marginHorizontal="24dp"
-    android:layout_marginVertical="24dp"
-    android:fitsSystemWindows="true">
+    android:paddingHorizontal="24dp"
+    android:paddingVertical="24dp">
 
     <com.google.android.material.textview.MaterialTextView
         android:id="@+id/text_view_faq"

app/src/main/res/values/ids.xml

@@ -1,4 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <item name="tag_edge_to_edge_padding" type="id" />
+    <item name="tag_edge_to_edge_margin" type="id" />
 </resources>