Dim the preference icons when its disabled

- Fix b/16956979

Change-Id: Idfa3fddf63746dea1db0c75dedab06b57aaf5de7

src/com/android/settings/location/DimmableIconPreference.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.location;
+
+import android.content.Context;
+import android.graphics.drawable.Drawable;
+import android.preference.Preference;
+import android.util.AttributeSet;
+
+/**
+ * A preference item that can dim the icon when it's disabled, either directly or because its parent
+ * is disabled.
+ */
+public class DimmableIconPreference extends Preference {
+    private static final int ICON_ALPHA_ENABLED = 255;
+    private static final int ICON_ALPHA_DISABLED = 102;
+
+    public DimmableIconPreference(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+    }
+
+    public DimmableIconPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public DimmableIconPreference(Context context) {
+        super(context);
+    }
+
+    private void dimIcon(boolean dimmed) {
+        Drawable icon = getIcon();
+        if (icon != null) {
+            icon.mutate().setAlpha(dimmed ? ICON_ALPHA_DISABLED : ICON_ALPHA_ENABLED);
+            setIcon(icon);
+        }
+    }
+
+    @Override
+    public void onParentChanged(Preference parent, boolean disableChild) {
+        dimIcon(disableChild);
+        super.onParentChanged(parent, disableChild);
+    }
+
+    @Override
+    public void setEnabled(boolean enabled) {
+        dimIcon(!enabled);
+        super.setEnabled(enabled);
+    }
+}

src/com/android/settings/location/InjectedSetting.java

@@ -23,7 +23,7 @@ import com.android.internal.annotations.Immutable;
 import com.android.internal.util.Preconditions;
 
 /**
- * Specifies a setting that is being injected into Settings > Location > Location services.
+ * Specifies a setting that is being injected into Settings > Location > Location services.
  *
  * @see android.location.SettingInjectorService
  */

src/com/android/settings/location/RecentLocationApps.java

@@ -81,7 +81,7 @@ public class RecentLocationApps {
      * Subclass of {@link Preference} to intercept views and allow content description to be set on
      * them for accessibility purposes.
      */
-    private static class AccessiblePreference extends Preference {
+    private static class AccessiblePreference extends DimmableIconPreference {
         public CharSequence mContentDescription;
 
         public AccessiblePreference(Context context, CharSequence contentDescription) {

src/com/android/settings/location/SettingsInjector.java

@@ -247,7 +247,7 @@ class SettingsInjector {
      * Adds an injected setting to the root.
      */
     private Preference addServiceSetting(List<Preference> prefs, InjectedSetting info) {
-        Preference pref = new Preference(mContext);
+        Preference pref = new DimmableIconPreference(mContext);
         pref.setTitle(info.title);
         pref.setSummary(null);
         PackageManager pm = mContext.getPackageManager();