The view ElevationShadowView is now used to visualize elevations.

library/src/main/java/de/mrapp/android/preference/activity/PreferenceActivity.java

@@ -42,7 +42,6 @@
 import android.widget.AdapterView.OnItemClickListener;
 import android.widget.Button;
 import android.widget.FrameLayout;
-import android.widget.ImageView;
 import android.widget.ListView;
 
 import java.util.ArrayList;
@@ -60,6 +59,7 @@
 import de.mrapp.android.util.ElevationUtil;
 import de.mrapp.android.util.ElevationUtil.Orientation;
 import de.mrapp.android.util.VisibleForTesting;
+import de.mrapp.android.util.view.ElevationShadowView;
 
 import static de.mrapp.android.util.Condition.ensureAtLeast;
 import static de.mrapp.android.util.Condition.ensureAtMaximum;
@@ -267,10 +267,10 @@ public abstract class PreferenceActivity extends AppCompatActivity
     private Toolbar breadCrumbToolbar;
 
     /**
-     * The image view, which is used to draw a shadow below the toolbar, which is used to show the
-     * bread crumb of the currently selected preference header on devices with a large screen.
+     * The view, which is used to draw a shadow below the toolbar, which is used to show the bread
+     * crumb of the currently selected preference header on devices with a large screen.
      */
-    private ImageView breadCrumbShadowView;
+    private ElevationShadowView breadCrumbShadowView;
 
     /**
      * The view group, which contains the buttons, which are shown when the activity is used as a
@@ -296,15 +296,15 @@ public abstract class PreferenceActivity extends AppCompatActivity
     private Button finishButton;
 
     /**
-     * The image view, which is used to draw a shadow below the activity's toolbar.
+     * The view, which is used to draw a shadow below the activity's toolbar.
      */
-    private ImageView toolbarShadowView;
+    private ElevationShadowView toolbarShadowView;
 
     /**
-     * The image view, which is used to draw a shadow above the button bar when the activity is used
-     * as a wizard.
+     * The view, which is used to draw a shadow above the button bar when the activity is used as a
+     * wizard.
      */
-    private ImageView buttonBarShadowView;
+    private ElevationShadowView buttonBarShadowView;
 
     /**
      * The preference header, which is currently selected or null, if no preference header is
@@ -360,28 +360,12 @@ public abstract class PreferenceActivity extends AppCompatActivity
      */
     private boolean navigationHidden;
 
-    /**
-     * The elevation of the toolbar in dp.
-     */
-    private int toolbarElevation;
-
-    /**
-     * The elevation of the toolbar, which is used to show the bread crumb of the currently selected
-     * preference header on devices with a large screen.
-     */
-    private int breadCrumbElevation;
-
     /**
      * The elevation of the view group, which contains the views, which are shown when a preference
      * screen is selected on a device with a large screen, in dp.
      */
     private int preferenceScreenElevation;
 
-    /**
-     * The elevation of the button bar in dp.
-     */
-    private int buttonBarElevation;
-
     /**
      * True, if the progress should be shown as the bread crumb title, when the activity is used as
      * a wizard, false otherwise.
@@ -1875,7 +1859,8 @@ public final void showButtonBar(final boolean showButtonBar) {
         if (showButtonBar) {
             buttonBar = (ViewGroup) findViewById(R.id.wizard_button_bar);
             buttonBar.setVisibility(View.VISIBLE);
-            buttonBarShadowView = (ImageView) findViewById(R.id.wizard_button_bar_shadow_view);
+            buttonBarShadowView =
+                    (ElevationShadowView) findViewById(R.id.wizard_button_bar_shadow_view);
             buttonBarShadowView.setVisibility(View.VISIBLE);
             nextButton = (Button) findViewById(R.id.next_button);
             nextButton.setOnClickListener(createNextButtonListener());
@@ -1936,7 +1921,7 @@ public final int getSelectedPreferenceHeaderPosition() {
      * @return The elevation of the activity's toolbar in dp as an {@link Integer} value
      */
     public final int getToolbarElevation() {
-        return toolbarElevation;
+        return toolbarShadowView.getShadowElevation();
     }
 
     /**
@@ -1947,9 +1932,7 @@ public final int getToolbarElevation() {
      *         must be at least 0 and at maximum 16
      */
     public final void setToolbarElevation(final int elevation) {
-        Bitmap shadow = createElevationShadow(this, elevation, Orientation.BOTTOM, true);
-        toolbarElevation = elevation;
-        toolbarShadowView.setImageBitmap(shadow);
+        toolbarShadowView.setShadowElevation(elevation);
     }
 
     /**
@@ -1962,7 +1945,7 @@ public final void setToolbarElevation(final int elevation) {
      */
     public final int getBreadCrumbElevation() {
         if (isSplitScreen()) {
-            return breadCrumbElevation;
+            return breadCrumbShadowView.getShadowElevation();
         }
 
         return -1;
@@ -1979,11 +1962,8 @@ public final int getBreadCrumbElevation() {
      * @return True, if the elevation has been set, false otherwise
      */
     public final boolean setBreadCrumbElevation(final int elevation) {
-        Bitmap shadow = createElevationShadow(this, elevation, Orientation.BOTTOM, true);
-
         if (breadCrumbShadowView != null) {
-            breadCrumbElevation = elevation;
-            breadCrumbShadowView.setImageBitmap(shadow);
+            breadCrumbShadowView.setShadowElevation(elevation);
             return true;
         }
 
@@ -2040,7 +2020,7 @@ public final boolean setPreferenceScreenElevation(final int elevation) {
      */
     public final int getButtonBarElevation() {
         if (isButtonBarShown()) {
-            return buttonBarElevation;
+            return buttonBarShadowView.getShadowElevation();
         }
 
         return -1;
@@ -2060,8 +2040,7 @@ public final boolean setButtonBarElevation(final int elevation) {
         Bitmap shadow = createElevationShadow(this, elevation, Orientation.TOP, true);
 
         if (buttonBarShadowView != null) {
-            buttonBarElevation = elevation;
-            buttonBarShadowView.setImageBitmap(shadow);
+            buttonBarShadowView.setShadowElevation(elevation);
             return true;
         }
 
@@ -2475,11 +2454,11 @@ protected void onCreate(final Bundle savedInstanceState) {
         preferenceHeaderParentView = (ViewGroup) findViewById(R.id.preference_header_parent);
         preferenceScreenParentView = (ViewGroup) findViewById(R.id.preference_screen_parent);
         preferenceScreenContainer = (CardView) findViewById(R.id.preference_screen_container);
-        toolbarShadowView = (ImageView) findViewById(R.id.toolbar_shadow_view);
+        toolbarShadowView = (ElevationShadowView) findViewById(R.id.toolbar_shadow_view);
 
         if (isSplitScreen()) {
             breadCrumbToolbar = (Toolbar) findViewById(R.id.bread_crumb_toolbar);
-            breadCrumbShadowView = (ImageView) findViewById(R.id.bread_crumb_shadow_view);
+            breadCrumbShadowView = (ElevationShadowView) findViewById(R.id.bread_crumb_shadow_view);
         }
 
         preferenceHeaderFragment = new PreferenceHeaderFragment();

library/src/main/java/de/mrapp/android/preference/activity/PreferenceFragment.java

@@ -19,7 +19,6 @@
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
 import android.content.res.TypedArray;
-import android.graphics.Bitmap;
 import android.graphics.drawable.ColorDrawable;
 import android.graphics.drawable.Drawable;
 import android.os.Bundle;
@@ -39,7 +38,6 @@
 import android.view.ViewGroup;
 import android.widget.Button;
 import android.widget.FrameLayout;
-import android.widget.ImageView;
 import android.widget.LinearLayout;
 import android.widget.ListView;
 
@@ -49,11 +47,10 @@
 import de.mrapp.android.preference.activity.animation.HideViewOnScrollAnimation;
 import de.mrapp.android.preference.activity.animation.HideViewOnScrollAnimation.Direction;
 import de.mrapp.android.preference.activity.decorator.PreferenceDecorator;
-import de.mrapp.android.util.ElevationUtil.Orientation;
+import de.mrapp.android.util.view.ElevationShadowView;
 
 import static de.mrapp.android.util.Condition.ensureNotNull;
 import static de.mrapp.android.util.DisplayUtil.pixelsToDp;
-import static de.mrapp.android.util.ElevationUtil.createElevationShadow;
 
 /**
  * A fragment, which allows to show multiple preferences. Additionally, a button, which allows to
@@ -112,9 +109,9 @@ public abstract class PreferenceFragment extends android.preference.PreferenceFr
     private ViewGroup buttonBar;
 
     /**
-     * The image view, which is used to draw a shadow above the button bar.
+     * The view, which is used to draw a shadow above the button bar.
      */
-    private ImageView shadowView;
+    private ElevationShadowView shadowView;
 
     /**
      * The button, which allows to restore the preferences' default values.
@@ -160,7 +157,7 @@ private void inflateRestoreDefaultsButtonBar() {
             restoreDefaultsButton =
                     (Button) buttonBarParent.findViewById(R.id.restore_defaults_button);
             restoreDefaultsButton.setOnClickListener(createRestoreDefaultsListener());
-            shadowView = (ImageView) buttonBarParent
+            shadowView = (ElevationShadowView) buttonBarParent
                     .findViewById(R.id.restore_defaults_button_bar_shadow_view);
             obtainStyledAttributes();
         }
@@ -633,11 +630,9 @@ public final int getButtonBarElevation() {
      */
     @SuppressWarnings("deprecation")
     public final boolean setButtonBarElevation(final int elevation) {
-        Bitmap shadow = createElevationShadow(getActivity(), elevation, Orientation.TOP, true);
-
         if (isRestoreDefaultsButtonShown()) {
-            this.buttonBarElevation = elevation;
-            shadowView.setImageBitmap(shadow);
+            buttonBarElevation = elevation;
+            shadowView.setShadowElevation(elevation);
             return true;
         }
 

library/src/main/res/layout-large/preference_activity.xml

@@ -18,6 +18,7 @@ not, see <http://www.gnu.org/licenses/>.
     android:id="@id/preference_activity_frame_layout"
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:custom="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
@@ -45,13 +46,13 @@ not, see <http://www.gnu.org/licenses/>.
                 android:layout_height="match_parent"
                 android:background="@color/navigation_background_light"/>
 
-            <ImageView
+            <de.mrapp.android.util.view.ElevationShadowView
                 android:id="@id/toolbar_shadow_view"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="top"
-                android:contentDescription="@null"
-                android:scaleType="fitXY"/>
+                custom:emulateParallelLight="true"
+                custom:shadowOrientation="bottom"/>
         </FrameLayout>
     </LinearLayout>
 
@@ -93,22 +94,22 @@ not, see <http://www.gnu.org/licenses/>.
                     android:layout_width="match_parent"
                     android:layout_height="match_parent"/>
 
-                <ImageView
+                <de.mrapp.android.util.view.ElevationShadowView
                     android:id="@id/bread_crumb_shadow_view"
                     android:layout_width="match_parent"
                     android:layout_height="wrap_content"
                     android:layout_gravity="top"
-                    android:contentDescription="@null"
-                    android:scaleType="fitXY"/>
+                    custom:emulateParallelLight="true"
+                    custom:shadowOrientation="bottom"/>
 
-                <ImageView
+                <de.mrapp.android.util.view.ElevationShadowView
                     android:id="@id/wizard_button_bar_shadow_view"
                     android:layout_width="match_parent"
                     android:layout_height="wrap_content"
                     android:layout_gravity="bottom"
-                    android:contentDescription="@null"
-                    android:scaleType="fitXY"
-                    android:visibility="gone"/>
+                    android:visibility="gone"
+                    custom:emulateParallelLight="true"
+                    custom:shadowOrientation="top"/>
             </FrameLayout>
 
             <include layout="@layout/wizard_button_bar"/>

library/src/main/res/layout-v21/restore_defaults_button_bar.xml

@@ -15,16 +15,17 @@ You should have received a copy of the GNU Lesser General Public License along w
 not, see <http://www.gnu.org/licenses/>.
 -->
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+              xmlns:custom="http://schemas.android.com/apk/res-auto"
               android:layout_width="match_parent"
               android:layout_height="wrap_content"
               android:orientation="vertical">
 
-    <ImageView
+    <de.mrapp.android.util.view.ElevationShadowView
         android:id="@id/restore_defaults_button_bar_shadow_view"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:contentDescription="@null"
-        android:scaleType="fitXY"/>
+        custom:emulateParallelLight="true"
+        custom:shadowOrientation="top"/>
 
     <RelativeLayout
         android:id="@id/restore_defaults_button_bar"

library/src/main/res/layout/preference_activity.xml

@@ -18,6 +18,7 @@ not, see <http://www.gnu.org/licenses/>.
     android:id="@id/preference_activity_frame_layout"
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:custom="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
@@ -46,13 +47,13 @@ not, see <http://www.gnu.org/licenses/>.
                 android:layout_height="match_parent"
                 android:background="@color/navigation_background_light"/>
 
-            <ImageView
+            <de.mrapp.android.util.view.ElevationShadowView
                 android:id="@id/toolbar_shadow_view"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_gravity="top"
-                android:contentDescription="@null"
-                android:scaleType="fitXY"/>
+                custom:emulateParallelLight="true"
+                custom:shadowOrientation="bottom"/>
 
             <ImageView
                 android:id="@id/wizard_button_bar_shadow_view"

library/src/main/res/layout/restore_defaults_button_bar.xml

@@ -15,16 +15,17 @@ You should have received a copy of the GNU Lesser General Public License along w
 not, see <http://www.gnu.org/licenses/>.
 -->
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+              xmlns:custom="http://schemas.android.com/apk/res-auto"
               android:layout_width="match_parent"
               android:layout_height="wrap_content"
               android:orientation="vertical">
 
-    <ImageView
+    <de.mrapp.android.util.view.ElevationShadowView
         android:id="@id/restore_defaults_button_bar_shadow_view"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:contentDescription="@null"
-        android:scaleType="fitXY"/>
+        custom:emulateParallelLight="true"
+        custom:shadowOrientation="top"/>
 
     <RelativeLayout
         android:id="@id/restore_defaults_button_bar"