direct link from settings to huaweis protected apps

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

@@ -7,6 +7,7 @@ import android.content.Intent;
 import android.content.SharedPreferences;
 import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
 import android.content.pm.PackageManager;
+import android.content.pm.ResolveInfo;
 import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
@@ -98,6 +99,15 @@ public class SettingsActivity extends XmppActivity implements
 			}
 		}
 
+		//this feature is only available on Huawei Android 6.
+		PreferenceScreen huaweiPreferenceScreen = (PreferenceScreen) mSettingsFragment.findPreference("huawei");
+		Intent intent = huaweiPreferenceScreen.getIntent();
+		//remove when Api version is above M (Version 6.0) or if the intent is not callable
+		if (Build.VERSION.SDK_INT > Build.VERSION_CODES.M || !isCallable(intent)) {
+			PreferenceCategory generalCategory = (PreferenceCategory) mSettingsFragment.findPreference("general");
+			generalCategory.removePreference(huaweiPreferenceScreen);
+		}
+
 		boolean removeLocation = new Intent("eu.siacs.conversations.location.request").resolveActivity(getPackageManager()) == null;
 		boolean removeVoice = new Intent(MediaStore.Audio.Media.RECORD_SOUND_ACTION).resolveActivity(getPackageManager()) == null;
 
@@ -222,6 +232,11 @@ public class SettingsActivity extends XmppActivity implements
 		});
 	}
 
+	private boolean isCallable(Intent intent) {
+		return getPackageManager().queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY).size() > 0;
+	}
+
+
 	private void cleanCache() {
 		Intent intent = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
 		intent.setData(Uri.parse("package:" + getPackageName()));

src/main/res/values/strings.xml

@@ -733,4 +733,6 @@
 	<string name="message_copied_to_clipboard">Message copied to clipboard</string>
 	<string name="message">Message</string>
 	<string name="private_messages_are_disabled">Private messages are disabled</string>
+	<string name="huawei_protected_apps">Protected Apps</string>
+	<string name="huawei_protected_apps_summary">To keep receiving notifications, even when the screen is turned off, you need to add Conversations to the list of protected apps.</string>
 </resources>

src/main/res/xml/preferences.xml

@@ -2,7 +2,8 @@
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
     android:background="?attr/color_background_secondary">
 
-    <PreferenceCategory android:title="@string/pref_general">
+    <PreferenceCategory android:title="@string/pref_general"
+        android:key="general">
         <CheckBoxPreference
             android:defaultValue="@bool/grant_new_contacts"
             android:key="grant_new_contacts"
@@ -16,6 +17,15 @@
             android:key="resource"
             android:summary="@string/pref_xmpp_resource_summary"
             android:title="@string/pref_xmpp_resource"/>
+        <PreferenceScreen
+            android:key="huawei"
+            android:title="@string/huawei_protected_apps"
+            android:summary="@string/huawei_protected_apps_summary"
+            >
+            <intent
+                android:targetPackage="com.huawei.systemmanager"
+                android:targetClass="com.huawei.systemmanager.optimize.process.ProtectActivity"/>
+        </PreferenceScreen>
     </PreferenceCategory>
     <PreferenceCategory android:title="@string/pref_privacy">
         <CheckBoxPreference