[TabLayout] Add selectedTabTextAppearance attribute

Resolves #2159 PiperOrigin-RevId: 477238120
material-components · Sep 27, 2022 · 00220d0 · 00220d0
1 parent 1322e61
commit 00220d0
Show file tree

Hide file tree

Showing 4 changed files with 69 additions and 9 deletions.
diff --git a/docs/components/Tabs.md b/docs/components/Tabs.md
@@ -361,12 +361,16 @@ Element   | Attribute      | Related method(s)
 
 ### Tab item text label attributes
 
-Element          | Attribute           | Related method(s)                                               | Default value
----------------- | ------------------- | --------------------------------------------------------------- | -------------
-**Text**         | `android:text`      | `setText`<br>`getText`                                          | `null`
-**Color**        | `tabTextColor`      | `setTabTextColors`<br>`getTabTextColors`                        | `colorOnSurfaceVariant` and `colorPrimary` (activated) (see all [states](https://github.com/material-components/material-components-android/tree/master/lib/java/com/google/android/material/tabs/res/color/m3_tabs_icon_color.xml))
-**Typography**   | `tabTextAppearance` | N/A                                                             | `?attr/textAppearanceLabelLarge`
-**Inline label** | `tabInlineLabel`    | `setInlineLabel`<br>`setInlineLabelResource`<br>`isInlineLabel` | `false`
+Element                   | Attribute                   | Related method(s)                                               | Default value
+------------------------- | --------------------------- | --------------------------------------------------------------- | -------------
+**Text**                  | `android:text`              | `setText`<br>`getText`                                          | `null`
+**Color**                 | `tabTextColor`              | `setTabTextColors`<br>`getTabTextColors`                        | `colorOnSurfaceVariant` and `colorPrimary` (activated) (see all [states](https://github.com/material-components/material-components-android/tree/master/lib/java/com/google/android/material/tabs/res/color/m3_tabs_icon_color.xml))
+**Typography**            | `tabTextAppearance`         | N/A                                                             | `?attr/textAppearanceLabelLarge`
+**Active tab typography** | `selectedTabTextAppearance` | N/A                                                             | None; will use `tabTextAppearance` instead
+**Inline label**          | `tabInlineLabel`            | `setInlineLabel`<br>`setInlineLabelResource`<br>`isInlineLabel` | `false`
+
+**Note:** When using `selectedTabTextAppearance`, you must have matching text
+attributes in `tabTextAppearance` to avoid unintended behavior.
 
 ### Tab item container attributes
 

diff --git a/lib/java/com/google/android/material/tabs/TabLayout.java b/lib/java/com/google/android/material/tabs/TabLayout.java
@@ -451,7 +451,9 @@ public interface BaseOnTabSelectedListener<T extends Tab> {
   int tabPaddingEnd;
   int tabPaddingBottom;
 
-  int tabTextAppearance;
+  private final int defaultTabTextAppearance;
+  private final int tabTextAppearance;
+  private int selectedTabTextAppearance = -1;
   ColorStateList tabTextColors;
   ColorStateList tabIconTint;
   ColorStateList tabRippleColorStateList;
@@ -460,6 +462,7 @@ public interface BaseOnTabSelectedListener<T extends Tab> {
 
   android.graphics.PorterDuff.Mode tabIconTintMode;
   float tabTextSize;
+  float selectedTabTextSize;
   float tabTextMultiLineSize;
 
   final int tabBackgroundResId;
@@ -566,6 +569,11 @@ public TabLayout(@NonNull Context context, @Nullable AttributeSet attrs, int def
     tabPaddingBottom =
         a.getDimensionPixelSize(R.styleable.TabLayout_tabPaddingBottom, tabPaddingBottom);
 
+    if (ThemeEnforcement.isMaterial3Theme(context)) {
+      defaultTabTextAppearance = R.attr.textAppearanceLabelLarge;
+    } else {
+      defaultTabTextAppearance = R.attr.textAppearanceButton;
+    }
     tabTextAppearance =
         a.getResourceId(R.styleable.TabLayout_tabTextAppearance, R.style.TextAppearance_Design_Tab);
 
@@ -586,6 +594,43 @@ public TabLayout(@NonNull Context context, @Nullable AttributeSet attrs, int def
       ta.recycle();
     }
 
+    if (a.hasValue(R.styleable.TabLayout_tabSelectedTextAppearance)) {
+      selectedTabTextAppearance =
+          a.getResourceId(R.styleable.TabLayout_tabSelectedTextAppearance, tabTextAppearance);
+    }
+
+    if (selectedTabTextAppearance != -1) {
+      // If there is a selected tab text appearance specified, we take the selected tab text size
+      // and selected color from it.
+      @SuppressLint("CustomViewStyleable")
+      final TypedArray selectedTabTA =
+          context.obtainStyledAttributes(
+              selectedTabTextAppearance, androidx.appcompat.R.styleable.TextAppearance);
+
+      try {
+        selectedTabTextSize =
+            selectedTabTA.getDimensionPixelSize(
+                androidx.appcompat.R.styleable.TextAppearance_android_textSize,
+                (int) tabTextSize);
+        ColorStateList selectedTabTextColor =
+            MaterialResources.getColorStateList(
+                context,
+                selectedTabTA,
+                androidx.appcompat.R.styleable.TextAppearance_android_textColor);
+        // Merge the selected tab color if it's set in the selected tab text appearance.
+        if (selectedTabTextColor != null) {
+          tabTextColors =
+              createColorStateList(
+                  tabTextColors.getDefaultColor(),
+                  selectedTabTextColor.getColorForState(
+                      new int[] {android.R.attr.state_selected},
+                      selectedTabTextColor.getDefaultColor()));
+        }
+      } finally {
+        selectedTabTA.recycle();
+      }
+    }
+
     if (a.hasValue(R.styleable.TabLayout_tabTextColor)) {
       // If we have an explicit text color set, use it instead
       tabTextColors =
@@ -1900,11 +1945,14 @@ public void selectTab(@Nullable final Tab tab, boolean updateIndicator) {
       // Setting selectedTab before dispatching 'tab unselected' events, so that currentTab's state
       // will be interpreted as unselected
       selectedTab = tab;
-      if (currentTab != null) {
+      // If the current tab is still attached to the TabLayout.
+      if (currentTab != null && currentTab.parent != null) {
         dispatchTabUnselected(currentTab);
+        currentTab.view.update();
       }
       if (tab != null) {
         dispatchTabSelected(tab);
+        tab.view.update();
       }
     }
   }
@@ -2690,7 +2738,12 @@ final void update() {
           inflateAndAddDefaultTextView();
           defaultMaxLines = TextViewCompat.getMaxLines(this.textView);
         }
-        TextViewCompat.setTextAppearance(this.textView, tabTextAppearance);
+        TextViewCompat.setTextAppearance(this.textView, defaultTabTextAppearance);
+        if (isSelected() && selectedTabTextAppearance != -1) {
+          TextViewCompat.setTextAppearance(this.textView, selectedTabTextAppearance);
+        } else {
+          TextViewCompat.setTextAppearance(this.textView, tabTextAppearance);
+        }
         if (tabTextColors != null) {
           this.textView.setTextColor(tabTextColors);
         }

diff --git a/lib/java/com/google/android/material/tabs/res-public/values/public.xml b/lib/java/com/google/android/material/tabs/res-public/values/public.xml
@@ -41,6 +41,7 @@
   <public name="tabStyle" type="attr"/>
   <public name="tabSecondaryStyle" type="attr"/>
   <public name="tabTextAppearance" type="attr"/>
+  <public name="tabSelectedTextAppearance" type="attr"/>
   <public name="tabTextColor" type="attr"/>
   <public name="Widget.Design.TabLayout" type="style"/>
   <public name="Widget.MaterialComponents.TabLayout" type="style"/>

diff --git a/lib/java/com/google/android/material/tabs/res/values/attrs.xml b/lib/java/com/google/android/material/tabs/res/values/attrs.xml
@@ -96,6 +96,8 @@
     <!-- {@deprecated Instead, provide a ColorStateList to the tabTextColor attribute with a
          selected color set.}  -->
     <attr name="tabSelectedTextColor" format="color"/>
+    <!-- A reference to a TextAppearance style to be applied to selected tab. -->
+    <attr name="tabSelectedTextAppearance" format="reference"/>
     <!-- The preferred padding along the start edge of tabs. -->
     <attr name="tabPaddingStart" format="dimension"/>
     <!-- The preferred padding along the top edge of tabs. -->