Improve collapsing toolbar state (#7277)

First this commit improves the threshold at which the icon color is
changed. We now ask the collapsing toolbar at which size it will be
collapsed instead of guessing.

Second, this commit also sets the appbar title (when collapsed) to the
podcast name in the podcast episode view.

5 files changed, 44 insertions, 21 deletions

diff --git a/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/FeedInfoFragment.java b/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/FeedInfoFragment.java
index 56164a819..6169e3888 100644
--- a/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/FeedInfoFragment.java
+++ b/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/FeedInfoFragment.java
@@ -105,7 +105,6 @@ public class FeedInfoFragment extends Fragment implements MaterialToolbar.OnMenu
 
         ToolbarIconTintManager iconTintManager =
                 new ToolbarIconTintManager(viewBinding.toolbar, viewBinding.collapsingToolbar);
-        iconTintManager.updateTint();
         viewBinding.appBar.addOnOffsetChangedListener(iconTintManager);
 
         viewBinding.header.butShowInfo.setVisibility(View.INVISIBLE);
diff --git a/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/FeedItemlistFragment.java b/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/FeedItemlistFragment.java
index 6dbab44a8..2d5d8fa35 100644
--- a/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/FeedItemlistFragment.java
+++ b/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/FeedItemlistFragment.java
@@ -51,6 +51,7 @@ import de.danoeh.antennapod.ui.TransitionEffect;
 import de.danoeh.antennapod.ui.appstartintent.MainActivityStarter;
 import de.danoeh.antennapod.ui.cleaner.HtmlToPlainText;
 import de.danoeh.antennapod.ui.common.IntentUtils;
+import de.danoeh.antennapod.ui.common.OnCollapseChangeListener;
 import de.danoeh.antennapod.ui.episodeslist.EpisodeItemListAdapter;
 import de.danoeh.antennapod.ui.episodeslist.EpisodeItemViewHolder;
 import de.danoeh.antennapod.ui.episodeslist.EpisodeMultiSelectActionHandler;
@@ -161,8 +162,16 @@ public class FeedItemlistFragment extends Fragment implements AdapterView.OnItem
 
         ToolbarIconTintManager iconTintManager =
                 new ToolbarIconTintManager(viewBinding.toolbar, viewBinding.collapsingToolbar);
-        iconTintManager.updateTint();
         viewBinding.appBar.addOnOffsetChangedListener(iconTintManager);
+        viewBinding.appBar.addOnOffsetChangedListener(new OnCollapseChangeListener(viewBinding.collapsingToolbar) {
+            @Override
+            public void onCollapseChanged(boolean isCollapsed) {
+                if (feed == null) {
+                    return;
+                }
+                viewBinding.toolbar.setTitle(isCollapsed ? feed.getTitle() : "");
+            }
+        });
 
         nextPageLoader = new MoreContentListFooterUtil(viewBinding.moreContent.moreContentListFooter);
         nextPageLoader.setClickListener(() -> {
diff --git a/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/ToolbarIconTintManager.java b/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/ToolbarIconTintManager.java
index 7b2104fba..11aa27557 100644
--- a/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/ToolbarIconTintManager.java
+++ b/app/src/main/java/de/danoeh/antennapod/ui/screen/feed/ToolbarIconTintManager.java
@@ -5,38 +5,27 @@ import android.graphics.PorterDuffColorFilter;
 import android.graphics.drawable.Drawable;
 import android.view.Menu;
 
-import com.google.android.material.appbar.MaterialToolbar;
-import com.google.android.material.appbar.AppBarLayout;
 import com.google.android.material.appbar.CollapsingToolbarLayout;
+import com.google.android.material.appbar.MaterialToolbar;
+
+import de.danoeh.antennapod.ui.common.OnCollapseChangeListener;
 
 /**
  * A manager that automatically finds all icons in a collapsable toolbar and tints them according to the collapse state
  * of the toolbar.
  */
-public class ToolbarIconTintManager implements AppBarLayout.OnOffsetChangedListener {
-    private final CollapsingToolbarLayout collapsingToolbar;
+public class ToolbarIconTintManager extends OnCollapseChangeListener {
     private final MaterialToolbar toolbar;
-    private boolean isTinted = false;
 
     public ToolbarIconTintManager(MaterialToolbar toolbar, CollapsingToolbarLayout collapsingToolbar) {
-        this.collapsingToolbar = collapsingToolbar;
+        super(collapsingToolbar);
         this.toolbar = toolbar;
+        this.onCollapseChanged(false);
     }
 
     @Override
-    public void onOffsetChanged(AppBarLayout appBarLayout, int offset) {
-        boolean tint  = (collapsingToolbar.getHeight() + offset) > (2 * collapsingToolbar.getMinimumHeight());
-        if (isTinted != tint) {
-            isTinted = tint;
-            updateTint();
-        }
-    }
-
-    public void updateTint() {
-        PorterDuffColorFilter filter = null;
-        if (isTinted) {
-            filter = new PorterDuffColorFilter(0xffffffff, Mode.SRC_ATOP);
-        }
+    public void onCollapseChanged(boolean isCollapsed) {
+        PorterDuffColorFilter filter = isCollapsed ? null : new PorterDuffColorFilter(0xffffffff, Mode.SRC_ATOP);
 
         safeSetColorFilter(toolbar.getNavigationIcon(), filter);
         safeSetColorFilter(toolbar.getOverflowIcon(), filter);
diff --git a/app/src/main/res/layout/feed_item_list_fragment.xml b/app/src/main/res/layout/feed_item_list_fragment.xml
index f236ee90a..f697288cd 100644
--- a/app/src/main/res/layout/feed_item_list_fragment.xml
+++ b/app/src/main/res/layout/feed_item_list_fragment.xml
@@ -16,6 +16,7 @@
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             app:scrimAnimationDuration="200"
+            app:titleEnabled="false"
             app:layout_scrollFlags="scroll|exitUntilCollapsed">
 
             <ImageView
diff --git a/ui/common/src/main/java/de/danoeh/antennapod/ui/common/OnCollapseChangeListener.java b/ui/common/src/main/java/de/danoeh/antennapod/ui/common/OnCollapseChangeListener.java
new file mode 100644
index 000000000..eaa698fb5
--- /dev/null
+++ b/ui/common/src/main/java/de/danoeh/antennapod/ui/common/OnCollapseChangeListener.java
@@ -0,0 +1,25 @@
+package de.danoeh.antennapod.ui.common;
+
+import com.google.android.material.appbar.AppBarLayout;
+import com.google.android.material.appbar.CollapsingToolbarLayout;
+
+public abstract class OnCollapseChangeListener implements AppBarLayout.OnOffsetChangedListener {
+    private final CollapsingToolbarLayout collapsingToolbar;
+    private boolean wasCollapsed = false;
+
+    public OnCollapseChangeListener(CollapsingToolbarLayout collapsingToolbar) {
+        this.collapsingToolbar = collapsingToolbar;
+    }
+
+    @Override
+    public void onOffsetChanged(AppBarLayout appBarLayout, int offset) {
+        boolean isCollapsed = (collapsingToolbar.getHeight() + offset)
+                < collapsingToolbar.getScrimVisibleHeightTrigger();
+        if (wasCollapsed != isCollapsed) {
+            wasCollapsed = isCollapsed;
+            onCollapseChanged(isCollapsed);
+        }
+    }
+
+    public abstract void onCollapseChanged(boolean isCollapsed);
+}