[FAB] Add customizable minTouchTargetSize attribute

Resolves material-components#5052

Author: pubiqq

lib/java/com/google/android/material/floatingactionbutton/FloatingActionButton.java

@@ -73,6 +73,7 @@
 import com.google.android.material.internal.ThemeEnforcement;
 import com.google.android.material.internal.ViewUtils;
 import com.google.android.material.internal.VisibilityAwareImageButton;
+import com.google.android.material.resources.MaterialAttributes;
 import com.google.android.material.resources.MaterialResources;
 import com.google.android.material.shadow.ShadowViewDelegate;
 import com.google.android.material.shape.ShapeAppearanceModel;
@@ -237,8 +238,6 @@ public FloatingActionButton(
     final float pressedTranslationZ =
         a.getDimension(R.styleable.FloatingActionButton_pressedTranslationZ, 0f);
     compatPadding = a.getBoolean(R.styleable.FloatingActionButton_useCompatPadding, false);
-    int minTouchTargetSize =
-        getResources().getDimensionPixelSize(R.dimen.mtrl_fab_min_touch_target);
 
     setMaxImageSize(a.getDimensionPixelSize(R.styleable.FloatingActionButton_maxImageSize, 0));
 
@@ -254,6 +253,11 @@ public FloatingActionButton(
     boolean ensureMinTouchTargetSize =
         a.getBoolean(R.styleable.FloatingActionButton_ensureMinTouchTargetSize, false);
 
+    int minTouchTargetSize =
+        a.getDimensionPixelSize(
+            R.styleable.FloatingActionButton_minTouchTargetSize,
+            MaterialAttributes.resolveMinimumAccessibleTouchTarget(context));
+
     setEnabled(a.getBoolean(R.styleable.FloatingActionButton_android_enabled, true));
 
     a.recycle();

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

@@ -38,9 +38,10 @@
     <attr name="fabCustomSize" format="dimension"/>
     <!-- Elevation value for the FAB -->
     <attr name="elevation"/>
-    <!-- Whether to extend the bounds of the FloatingActionButton to meet
-        @dimen/mtrl_fab_min_touch_target. -->
+    <!-- Whether to extend the bounds of the FAB to meet minTouchTargetSize. -->
     <attr name="ensureMinTouchTargetSize"/>
+    <!-- The minimum size of the FAB's touch target. -->
+    <attr name="minTouchTargetSize"/>
     <!-- TranslationZ value for the FAB when hovered, focused, or hovered and focused. -->
     <attr name="hoveredFocusedTranslationZ" format="dimension"/>
     <!-- TranslationZ value for the FAB when pressed-->

lib/java/com/google/android/material/floatingactionbutton/res/values/styles.xml

@@ -376,6 +376,7 @@
     <item name="android:background">@null</item>
     <item name="enforceMaterialTheme">true</item>
     <item name="ensureMinTouchTargetSize">true</item>
+    <item name="minTouchTargetSize">@dimen/mtrl_fab_min_touch_target</item>
     <item name="elevation">@dimen/mtrl_fab_elevation</item>
     <item name="backgroundTint">@color/mtrl_fab_bg_color_selector</item>
     <item name="tint">@color/mtrl_fab_icon_text_color_selector</item>