Showing a toast when changing wallaper is disabled

Bug: 27940102
Change-Id: I373093d9b85dca356aaa8798931d5315981fd74c
(cherry picked from commit 2afb636180)

res/values/strings.xml

@@ -164,6 +164,8 @@
     <string name="wallpaper_button_text">Wallpapers</string>
     <!-- Text for settings button -->
     <string name="settings_button_text">Settings</string>
+    <!-- Message shown when a feature is disabled by the administrator -->
+    <string name="msg_disabled_by_admin">Disabled by your admin</string>
 
     <!-- Strings for settings -->
     <!-- Title for Allow Rotation setting. [CHAR LIMIT=50] -->

src/com/android/launcher3/Launcher.java

@@ -2735,6 +2735,11 @@ public class Launcher extends Activity
      * on the home screen.
      */
     protected void onClickWallpaperPicker(View v) {
+        if (!Utilities.isWallapaperAllowed(this)) {
+            Toast.makeText(this, R.string.msg_disabled_by_admin, Toast.LENGTH_SHORT).show();
+            return;
+        }
+
         if (LOGD) Log.d(TAG, "onClickWallpaperPicker");
         int pageScroll = mWorkspace.getScrollForPage(mWorkspace.getPageNearestToCenterOfScreen());
         float offset = mWorkspace.mWallpaperOffset.wallpaperOffsetForScroll(pageScroll);

src/com/android/launcher3/Utilities.java

@@ -19,6 +19,7 @@ package com.android.launcher3;
 import android.annotation.TargetApi;
 import android.app.Activity;
 import android.app.SearchManager;
+import android.app.WallpaperManager;
 import android.appwidget.AppWidgetManager;
 import android.appwidget.AppWidgetProviderInfo;
 import android.content.ActivityNotFoundException;
@@ -45,6 +46,7 @@ import android.graphics.drawable.BitmapDrawable;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.PaintDrawable;
 import android.os.Build;
+import android.os.Build.VERSION_CODES;
 import android.os.Bundle;
 import android.os.PowerManager;
 import android.text.Spannable;
@@ -828,6 +830,17 @@ public final class Utilities {
         return ATLEAST_LOLLIPOP && powerManager.isPowerSaveMode();
     }
 
+    public static boolean isWallapaperAllowed(Context context) {
+        if (isNycOrAbove()) {
+            try {
+                WallpaperManager wm = context.getSystemService(WallpaperManager.class);
+                return (Boolean) wm.getClass().getDeclaredMethod("isWallpaperSettingAllowed")
+                        .invoke(wm);
+            } catch (Exception e) { }
+        }
+        return true;
+    }
+
     /**
      * An extension of {@link BitmapDrawable} which returns the bitmap pixel size as intrinsic size.
      * This allows the badging to be done based on the action bitmap size rather than