Tint selectableItemBackground with accent color for versions below 21

app/src/main/java/com/philliphsu/clock2/aospdatetimepicker/Utils.java

@@ -20,10 +20,10 @@ import android.animation.Keyframe;
 import android.animation.ObjectAnimator;
 import android.animation.PropertyValuesHolder;
 import android.annotation.SuppressLint;
-import android.annotation.TargetApi;
 import android.content.Context;
 import android.content.res.ColorStateList;
 import android.content.res.TypedArray;
+import android.graphics.PorterDuff;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.RippleDrawable;
 import android.os.Build;
@@ -247,16 +247,24 @@ public class Utils {
     }
 
     /**
-     * Sets the color on the {@code view}'s RippleDrawable background,
+     * Sets the color on the {@code view}'s {@code selectableItemBackground} or the
-     * if its background was set to {@code android.R.attr.selectableItemBackground} or
+     * borderless variant, whichever was set as the background.
-     * {@code android.R.attr.selectableItemBackgroundBorderless}.
      * @param view the view that should have its highlight color changed
      */
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
     public static void setColorControlHighlight(@NonNull View view, @ColorInt int color) {
         Drawable selectableItemBackground = view.getBackground();
-        if (selectableItemBackground instanceof RippleDrawable) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP
+                && selectableItemBackground instanceof RippleDrawable) {
             ((RippleDrawable) selectableItemBackground).setColor(ColorStateList.valueOf(color));
+        } else {
+            // Draws the color (src) onto the background (dest) *in the same plane*.
+            // That means the color is not overlapping (i.e. on a higher z-plane, covering)
+            // the background. That would be done with SRC_OVER.
+            // The DrawableCompat tinting APIs *could* be a viable alternative, if you
+            // call setTintMode(). Previous attempts using those APIs failed without
+            // the tint mode. However, those APIs have the overhead of mutating and wrapping
+            // the drawable.
+            selectableItemBackground.setColorFilter(color, PorterDuff.Mode.SRC_ATOP);
         }
     }
 

app/src/main/res/values-v21/styles.xml

@@ -6,4 +6,15 @@
         <item name="android:windowDrawsSystemBarBackgrounds">true</item>
         <item name="android:statusBarColor">@android:color/transparent</item>
     </style>
+
+    <style name="GridLayoutNumpadElement">
+        <!-- http://stackoverflow.com/a/6868308/5055032
+         Leave off the namespace to reference a custom attribute.
+         Here, we are referencing the "grid:" namespace -->
+        <item name="layout_columnWeight">1</item>
+        <!--<item name="layout_rowWeight">1</item>-->
+        <item name="android:layout_height">@dimen/numeric_keypad_cell_height</item>
+        <item name="android:background">?android:attr/selectableItemBackgroundBorderless</item>
+        <item name="android:gravity">center</item>
+    </style>
 </resources>

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

@@ -37,7 +37,7 @@
         <item name="layout_columnWeight">1</item>
         <!--<item name="layout_rowWeight">1</item>-->
         <item name="android:layout_height">@dimen/numeric_keypad_cell_height</item>
-        <item name="android:background">?android:attr/selectableItemBackgroundBorderless</item>
+        <item name="android:background">?android:attr/selectableItemBackground</item>
         <item name="android:gravity">center</item>
     </style>