From 45181aa712dc248686c50bda6249e3811d68ba1d Mon Sep 17 00:00:00 2001
From: Alex Ning <chineseperson5@gmail.com>
Date: Fri, 16 Jul 2021 21:01:39 +0800
Subject: [PATCH] Add column spacing to the RecyclerView in
 PostGalleryActivity.

---
 .../activities/PostGalleryActivity.java       | 34 +++++++++++++++++++
 .../main/res/layout/activity_post_gallery.xml |  4 ++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/app/src/main/java/ml/docilealligator/infinityforreddit/activities/PostGalleryActivity.java b/app/src/main/java/ml/docilealligator/infinityforreddit/activities/PostGalleryActivity.java
index e5410ff1..d296688f 100644
--- a/app/src/main/java/ml/docilealligator/infinityforreddit/activities/PostGalleryActivity.java
+++ b/app/src/main/java/ml/docilealligator/infinityforreddit/activities/PostGalleryActivity.java
@@ -3,8 +3,10 @@ package ml.docilealligator.infinityforreddit.activities;
 import android.content.ActivityNotFoundException;
 import android.content.Intent;
 import android.content.SharedPreferences;
+import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.graphics.Bitmap;
+import android.graphics.Rect;
 import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
@@ -24,6 +26,7 @@ import androidx.appcompat.widget.Toolbar;
 import androidx.coordinatorlayout.widget.CoordinatorLayout;
 import androidx.core.content.ContextCompat;
 import androidx.core.content.FileProvider;
+import androidx.recyclerview.widget.GridLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.bumptech.glide.Glide;
@@ -70,6 +73,7 @@ import ml.docilealligator.infinityforreddit.services.SubmitPostService;
 import ml.docilealligator.infinityforreddit.utils.JSONUtils;
 import ml.docilealligator.infinityforreddit.utils.SharedPreferencesUtils;
 import ml.docilealligator.infinityforreddit.utils.UploadImageUtils;
+import ml.docilealligator.infinityforreddit.utils.Utils;
 import pl.droidsonroids.gif.GifImageView;
 import retrofit2.Retrofit;
 
@@ -220,6 +224,36 @@ public class PostGalleryActivity extends BaseActivity implements FlairBottomShee
             }
         });
         imagesRecyclerView.setAdapter(adapter);
+        Resources resources = getResources();
+        int nColumns = resources.getBoolean(R.bool.isTablet) || resources.getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE ? 3 : 2;
+        ((GridLayoutManager) imagesRecyclerView.getLayoutManager()).setSpanCount(nColumns);
+        imagesRecyclerView.addItemDecoration(new RecyclerView.ItemDecoration() {
+            @Override
+            public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
+                GridLayoutManager.LayoutParams layoutParams = (GridLayoutManager.LayoutParams) view.getLayoutParams();
+
+                int spanIndex = layoutParams.getSpanIndex();
+
+                int offset = (int) (Utils.convertDpToPixel(16, PostGalleryActivity.this));
+                int halfOffset = offset / 2;
+
+                if (nColumns == 2) {
+                    if (spanIndex == 0) {
+                        outRect.set(halfOffset, 0, halfOffset, offset);
+                    } else {
+                        outRect.set(halfOffset, 0, halfOffset, offset);
+                    }
+                } else if (nColumns == 3) {
+                    if (spanIndex == 0) {
+                        outRect.set(halfOffset, 0, halfOffset, offset);
+                    } else if (spanIndex == 1) {
+                        outRect.set(halfOffset, 0, halfOffset, offset);
+                    } else {
+                        outRect.set(halfOffset, 0, halfOffset, offset);
+                    }
+                }
+            }
+        });
 
         if (savedInstanceState != null) {
             subredditName = savedInstanceState.getString(SUBREDDIT_NAME_STATE);
diff --git a/app/src/main/res/layout/activity_post_gallery.xml b/app/src/main/res/layout/activity_post_gallery.xml
index 80f87dc1..150870e0 100644
--- a/app/src/main/res/layout/activity_post_gallery.xml
+++ b/app/src/main/res/layout/activity_post_gallery.xml
@@ -191,7 +191,9 @@
                 android:id="@+id/images_recycler_view_post_gallery_activity"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
-                android:padding="16dp"
+                android:paddingTop="16dp"
+                android:paddingStart="8dp"
+                android:paddingEnd="8dp"
                 app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"
                 app:spanCount="2" />