Fixing notification image preview.

app/src/main/java/org/thoughtcrime/securesms/attachments/Attachment.java

@@ -108,6 +108,8 @@ public abstract class Attachment {
   @Nullable
   public abstract Uri getUri();
 
+  public abstract @Nullable Uri getPublicUri();
+
   public int getTransferState() {
     return transferState;
   }

app/src/main/java/org/thoughtcrime/securesms/attachments/DatabaseAttachment.java

@@ -65,6 +65,15 @@ public class DatabaseAttachment extends Attachment {
     }
   }
 
+  @Override
+  public @Nullable Uri getPublicUri() {
+    if (hasData) {
+      return PartAuthority.getAttachmentPublicUri(getUri());
+    } else {
+      return null;
+    }
+  }
+
   public AttachmentId getAttachmentId() {
     return attachmentId;
   }

app/src/main/java/org/thoughtcrime/securesms/attachments/MmsNotificationAttachment.java

@@ -20,6 +20,11 @@ public class MmsNotificationAttachment extends Attachment {
     return null;
   }
 
+  @Override
+  public @Nullable Uri getPublicUri() {
+    return null;
+  }
+
   private static int getTransferStateFromStatus(int status) {
     if (status == MmsDatabase.Status.DOWNLOAD_INITIALIZED ||
         status == MmsDatabase.Status.DOWNLOAD_NO_CONNECTIVITY)

app/src/main/java/org/thoughtcrime/securesms/attachments/PointerAttachment.java

@@ -46,6 +46,11 @@ public class PointerAttachment extends Attachment {
     return null;
   }
 
+  @Override
+  public @Nullable Uri getPublicUri() {
+    return null;
+  }
+
   public static List<Attachment> forPointers(Optional<List<SignalServiceAttachment>> pointers) {
     List<Attachment> results = new LinkedList<>();
 

app/src/main/java/org/thoughtcrime/securesms/attachments/TombstoneAttachment.java

@@ -23,4 +23,9 @@ public class TombstoneAttachment extends Attachment {
   public @Nullable Uri getUri() {
     return null;
   }
+
+  @Override
+  public @Nullable Uri getPublicUri() {
+    return null;
+  }
 }

app/src/main/java/org/thoughtcrime/securesms/attachments/UriAttachment.java

@@ -58,6 +58,11 @@ public class UriAttachment extends Attachment {
     return dataUri;
   }
 
+  @Override
+  public @Nullable Uri getPublicUri() {
+    return null;
+  }
+
   @Override
   public boolean equals(Object other) {
     return other != null && other instanceof UriAttachment && ((UriAttachment) other).dataUri.equals(this.dataUri);

app/src/main/java/org/thoughtcrime/securesms/mms/Slide.java

@@ -55,6 +55,10 @@ public abstract class Slide {
     return attachment.getUri();
   }
 
+  public @Nullable Uri getPublicUri() {
+    return attachment.getPublicUri();
+  }
+
   @NonNull
   public Optional<String> getBody() {
     return Optional.absent();

app/src/main/java/org/thoughtcrime/securesms/notifications/SingleRecipientNotificationBuilder.java

@@ -268,7 +268,12 @@ public class SingleRecipientNotificationBuilder extends AbstractNotificationBuil
     if (slideDeck != null && slideDeck.getThumbnailSlide() != null) {
       Slide thumbnail = slideDeck.getThumbnailSlide();
 
-      dataUri  = thumbnail.getUri();
+      if (Build.VERSION.SDK_INT >= 28) {
+        dataUri = thumbnail.getPublicUri();
+      } else {
+        dataUri  = thumbnail.getUri();
+      }
+
       mimeType = thumbnail.getContentType();
     }