change background if no results found in channel search. fixes #3559

src/main/java/eu/siacs/conversations/ui/ChannelDiscoveryActivity.java

@@ -32,6 +32,7 @@ import eu.siacs.conversations.services.ChannelDiscoveryService;
 import eu.siacs.conversations.ui.adapter.ChannelSearchResultAdapter;
 import eu.siacs.conversations.ui.util.PendingItem;
 import eu.siacs.conversations.ui.util.SoftKeyboardUtils;
+import eu.siacs.conversations.ui.util.StyledAttributes;
 import eu.siacs.conversations.utils.AccountUtils;
 import rocks.xmpp.addr.Jid;
 
@@ -128,6 +129,7 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
     private void toggleLoadingScreen() {
         adapter.submitList(Collections.emptyList());
         binding.progressBar.setVisibility(View.VISIBLE);
+        binding.list.setBackgroundColor(StyledAttributes.getColor(this, R.attr.color_background_primary));
     }
 
     @Override
@@ -172,11 +174,16 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
     }
 
     @Override
-    public void onChannelSearchResultsFound(List<MuclumbusService.Room> results) {
+    public void onChannelSearchResultsFound(final List<MuclumbusService.Room> results) {
         runOnUiThread(() -> {
             adapter.submitList(results);
             binding.list.setVisibility(View.VISIBLE);
             binding.progressBar.setVisibility(View.GONE);
+            if (results.size() == 0) {
+                binding.list.setBackground(StyledAttributes.getDrawable(this, R.attr.activity_primary_background_no_results));
+            } else {
+                binding.list.setBackgroundColor(StyledAttributes.getColor(this, R.attr.color_background_primary));
+            }
         });
 
     }

src/main/res/drawable/no_results_primary_background_dark.xml

@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (c) 2018, Daniel Gultsch All rights reserved.
+  ~
+  ~ Redistribution and use in source and binary forms, with or without modification,
+  ~ are permitted provided that the following conditions are met:
+  ~
+  ~ 1. Redistributions of source code must retain the above copyright notice, this
+  ~ list of conditions and the following disclaimer.
+  ~
+  ~ 2. Redistributions in binary form must reproduce the above copyright notice,
+  ~ this list of conditions and the following disclaimer in the documentation and/or
+  ~ other materials provided with the distribution.
+  ~
+  ~ 3. Neither the name of the copyright holder nor the names of its contributors
+  ~ may be used to endorse or promote products derived from this software without
+  ~ specific prior written permission.
+  ~
+  ~ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+  ~ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+  ~ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  ~ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+  ~ ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  ~ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  ~ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+  ~ ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  ~ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+  ~ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+  -->
+
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <item android:drawable="@color/grey800"/>
+
+    <item>
+        <bitmap
+            android:alpha="@dimen/background_image_opacity"
+            android:gravity="center"
+            android:src="@drawable/ic_no_results_background_white"/>
+    </item>
+</layer-list>

src/main/res/drawable/no_results_primary_background_light.xml

@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (c) 2018, Daniel Gultsch All rights reserved.
+  ~
+  ~ Redistribution and use in source and binary forms, with or without modification,
+  ~ are permitted provided that the following conditions are met:
+  ~
+  ~ 1. Redistributions of source code must retain the above copyright notice, this
+  ~ list of conditions and the following disclaimer.
+  ~
+  ~ 2. Redistributions in binary form must reproduce the above copyright notice,
+  ~ this list of conditions and the following disclaimer in the documentation and/or
+  ~ other materials provided with the distribution.
+  ~
+  ~ 3. Neither the name of the copyright holder nor the names of its contributors
+  ~ may be used to endorse or promote products derived from this software without
+  ~ specific prior written permission.
+  ~
+  ~ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+  ~ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+  ~ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  ~ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+  ~ ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  ~ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  ~ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+  ~ ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  ~ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+  ~ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+  -->
+
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <item android:drawable="@color/grey50"/>
+
+    <item>
+        <bitmap
+            android:alpha="@dimen/background_image_opacity"
+            android:gravity="center"
+            android:src="@drawable/ic_no_results_background_black"/>
+    </item>
+</layer-list>

src/main/res/values/attrs.xml

@@ -22,6 +22,7 @@
 
     <attr name="activity_background_search" format="reference"/>
     <attr name="activity_background_no_results" format="reference"/>
+    <attr name="activity_primary_background_no_results" format="reference"/>
 
     <attr name="list_item_background" format="reference"/>
 

src/main/res/values/themes.xml

@@ -18,6 +18,7 @@
 
         <item name="activity_background_search">@drawable/search_background_light</item>
         <item name="activity_background_no_results">@drawable/no_results_background_light</item>
+        <item name="activity_primary_background_no_results">@drawable/no_results_primary_background_light</item>
         <item name="list_item_background">@drawable/list_item_background_light</item>
 
         <item name="EmojiColor">@color/black</item>
@@ -127,6 +128,7 @@
         <item name="color_background_overlay">@color/black26</item>
         <item name="activity_background_search">@drawable/search_background_dark</item>
         <item name="activity_background_no_results">@drawable/no_results_background_dark</item>
+        <item name="activity_primary_background_no_results">@drawable/no_results_primary_background_dark</item>
         <item name="list_item_background">@drawable/list_item_background_dark</item>
         <item name="color_warning">@color/red_a100</item>