[CollapsingToolbarLayout] Added multiple subtitle support.

PiperOrigin-RevId: 713365011

Author: pekingme

catalog/java/io/material/catalog/topappbar/res/layout/cat_topappbar_collapsing_multiline_fragment.xml

@@ -35,7 +35,8 @@
       android:layout_width="match_parent"
       android:layout_height="?attr/collapsingToolbarLayoutLargeSize"
       app:layout_scrollFlags="scroll|exitUntilCollapsed|snap"
-      app:maxLines="3">
+      app:titleMaxLines="3"
+      app:subtitleMaxLines="3">
 
       <androidx.appcompat.widget.Toolbar
         android:id="@+id/toolbar"
@@ -44,8 +45,9 @@
         android:layout_height="?attr/actionBarSize"
         android:elevation="0dp"
         app:layout_collapseMode="pin"
+        tools:ignore="UnusedAttribute"
         app:title="@string/cat_topappbar_collapsing_multiline_demo_toolbar_title"
-        tools:ignore="UnusedAttribute" />
+        app:subtitle="@string/cat_topappbar_collapsing_multiline_demo_toolbar_subtitle" />
     </com.google.android.material.appbar.CollapsingToolbarLayout>
   </com.google.android.material.appbar.AppBarLayout>
 

catalog/java/io/material/catalog/topappbar/res/values/strings.xml

@@ -85,6 +85,8 @@
   <!-- Sample long title [CHAR_LIMIT=NONE] -->
   <string name="cat_topappbar_collapsing_multiline_demo_toolbar_title" description="Long title [CHAR_LIMIT=NONE]">This Collapsing Title is
     extremely long and thus will be displayed in multiple lines.</string>
+  <string name="cat_topappbar_collapsing_multiline_demo_toolbar_subtitle" description="Long subtitle [CHAR_LIMIT=NONE]">This Collapsing Subtitle is
+    extremely long and thus will be displayed in multiple lines.</string>
   <!-- Label for a button to change the maximum number of lines [CHAR_LIMIT=32] -->
   <string name="menu_max_lines">Max lines = <xliff:g id="max">%d</xliff:g></string>
 

lib/java/com/google/android/material/appbar/CollapsingToolbarLayout.java

@@ -196,7 +196,8 @@ public class CollapsingToolbarLayout extends FrameLayout {
   private int topInsetApplied = 0;
   private boolean forceApplySystemWindowInsetTop;
 
-  private int extraMultilineHeight = 0;
+  private int extraMultilineTitleHeight = 0;
+  private int extraMultilineSubtitleHeight = 0;
   private boolean extraMultilineHeightEnabled;
 
   private int extraHeightForTitles = 0;
@@ -307,7 +308,10 @@ public CollapsingToolbarLayout(
     scrimVisibleHeightTrigger =
         a.getDimensionPixelSize(R.styleable.CollapsingToolbarLayout_scrimVisibleHeightTrigger, -1);
 
-    if (a.hasValue(R.styleable.CollapsingToolbarLayout_maxLines)) {
+    if (a.hasValue(R.styleable.CollapsingToolbarLayout_titleMaxLines)) {
+      collapsingTitleHelper.setExpandedMaxLines(
+          a.getInt(R.styleable.CollapsingToolbarLayout_titleMaxLines, 1));
+    } else if (a.hasValue(R.styleable.CollapsingToolbarLayout_maxLines)) {
       collapsingTitleHelper.setExpandedMaxLines(
           a.getInt(R.styleable.CollapsingToolbarLayout_maxLines, 1));
     }
@@ -351,6 +355,10 @@ public CollapsingToolbarLayout(
           MaterialResources.getColorStateList(
               context, a, R.styleable.CollapsingToolbarLayout_collapsedSubtitleTextColor));
     }
+    if (a.hasValue(R.styleable.CollapsingToolbarLayout_subtitleMaxLines)) {
+      collapsingSubtitleHelper.setExpandedMaxLines(
+          a.getInt(R.styleable.CollapsingToolbarLayout_subtitleMaxLines, 1));
+    }
     if (a.hasValue(R.styleable.CollapsingToolbarLayout_titlePositionInterpolator)) {
       collapsingSubtitleHelper.setPositionInterpolator(
           android.view.animation.AnimationUtils.loadInterpolator(
@@ -690,23 +698,42 @@ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         extraHeightForTitles = 0;
       }
 
-      // Calculates the extra height needed for the multiline title, if needed.
-      if (extraMultilineHeightEnabled && collapsingTitleHelper.getExpandedMaxLines() > 1) {
-        int lineCount = collapsingTitleHelper.getExpandedLineCount();
-        if (lineCount > 1) {
-          // Add extra height based on the amount of height beyond the first line of title text.
-          int expandedTextHeight =
-              Math.round(collapsingTitleHelper.getExpandedTextFullSingleLineHeight());
-          extraMultilineHeight = expandedTextHeight * (lineCount - 1);
-        } else {
-          extraMultilineHeight = 0;
+      if (extraMultilineHeightEnabled) {
+        // Calculates the extra height needed for the multiline title, if needed.
+        if (collapsingTitleHelper.getExpandedMaxLines() > 1) {
+          int lineCount = collapsingTitleHelper.getExpandedLineCount();
+          if (lineCount > 1) {
+            // Add extra height based on the amount of height beyond the first line of title text.
+            int expandedTextHeight =
+                Math.round(collapsingTitleHelper.getExpandedTextFullSingleLineHeight());
+            extraMultilineTitleHeight = expandedTextHeight * (lineCount - 1);
+          } else {
+            extraMultilineTitleHeight = 0;
+          }
+        }
+        // Calculates the extra height needed for the multiline subtitle, if needed.
+        if (collapsingSubtitleHelper.getExpandedMaxLines() > 1) {
+          int lineCount = collapsingSubtitleHelper.getExpandedLineCount();
+          if (lineCount > 1) {
+            // Add extra height based on the amount of height beyond the first line of subtitle
+            // text.
+            int expandedTextHeight =
+                Math.round(collapsingSubtitleHelper.getExpandedTextFullSingleLineHeight());
+            extraMultilineSubtitleHeight = expandedTextHeight * (lineCount - 1);
+          } else {
+            extraMultilineSubtitleHeight = 0;
+          }
         }
       }
 
-      if (extraHeightForTitles + extraMultilineHeight > 0) {
+      if (extraHeightForTitles + extraMultilineTitleHeight + extraMultilineSubtitleHeight > 0) {
         heightMeasureSpec =
             MeasureSpec.makeMeasureSpec(
-                originalHeight + extraHeightForTitles + extraMultilineHeight, MeasureSpec.EXACTLY);
+                originalHeight
+                    + extraHeightForTitles
+                    + extraMultilineTitleHeight
+                    + extraMultilineSubtitleHeight,
+                MeasureSpec.EXACTLY);
         super.onMeasure(widthMeasureSpec, heightMeasureSpec);
       }
     }
@@ -790,15 +817,16 @@ private void updateTextBounds(
               titleBoundsRight,
               (int)
                   (titleBoundsBottom
-                      - collapsingSubtitleHelper.getExpandedTextFullSingleLineHeight()
+                      - (collapsingSubtitleHelper.getExpandedTextFullSingleLineHeight()
+                          + extraMultilineSubtitleHeight)
                       - expandedTitleSpacing),
               /* alignBaselineAtBottom= */ false);
           collapsingSubtitleHelper.setExpandedBounds(
               titleBoundsLeft,
               (int)
                   (titleBoundsTop
                       + (collapsingTitleHelper.getExpandedTextFullSingleLineHeight()
-                          + extraMultilineHeight)
+                          + extraMultilineTitleHeight)
                       + expandedTitleSpacing),
               titleBoundsRight,
               titleBoundsBottom,
@@ -1713,6 +1741,7 @@ public void setExpandedTitleSpacing(int titleSpacing) {
   @RestrictTo(LIBRARY_GROUP)
   public void setMaxLines(int maxLines) {
     collapsingTitleHelper.setExpandedMaxLines(maxLines);
+    collapsingSubtitleHelper.setExpandedMaxLines(maxLines);
   }
 
   /** Gets the maximum number of lines to display in the expanded state. Experimental Feature. */
@@ -1880,7 +1909,8 @@ public int getScrimVisibleHeightTrigger() {
       // If we have one explicitly set, return it
       return scrimVisibleHeightTrigger
           + topInsetApplied
-          + extraMultilineHeight
+          + extraMultilineTitleHeight
+          + extraMultilineSubtitleHeight
           + extraHeightForTitles;
     }
 

lib/java/com/google/android/material/appbar/res-public/values/public.xml

@@ -89,6 +89,8 @@
   <public name="scrimVisibleHeightTrigger" type="attr"/>
   <public name="titleEnabled" type="attr"/>
   <public name="maxLines" type="attr"/>
+  <public name="titleMaxLines" type="attr"/>
+  <public name="subtitleMaxLines" type="attr"/>
   <public name="titleCentered" type="attr"/>
   <public name="subtitleCentered" type="attr"/>
   <public name="titlePositionInterpolator" type="attr"/>

lib/java/com/google/android/material/appbar/res/values/attrs.xml

@@ -260,8 +260,11 @@
       <!-- The expanded title will fade out and translate, and the collapsed title will fade in. -->
       <enum name="fade" value="1"/>
     </attr>
-    <!-- The maximum number of lines to display in the expanded state. Experimental Feature. -->
+    <!-- The maximum number of lines to display the title in the expanded state. Experimental Feature. -->
     <attr name="maxLines" format="integer" />
+    <attr name="titleMaxLines" format="integer"/>
+    <!-- The maximum number of lines to display the subtitle in the expanded state. Experimental Feature. -->
+    <attr name="subtitleMaxLines" format="integer" />
     <!-- Whether the system window inset top should be applied regardless of
          what the layout_height is set to. Experimental Feature. -->
     <attr name="forceApplySystemWindowInsetTop" format="boolean" />