From 897161ad2cf2adc1a97238045de03054402a751d Mon Sep 17 00:00:00 2001
From: MinSoo Kim <minsoo8449@gmail.com>
Date: Sun, 23 Aug 2020 20:47:20 +0900
Subject: [PATCH] added feature that clearing current selection if max
 selectable is 1

---
 .../main/java/com/zhihu/matisse/SelectionCreator.java | 11 +++++++++++
 .../zhihu/matisse/internal/entity/SelectionSpec.java  |  2 ++
 .../internal/model/SelectedItemCollection.java        |  9 ++++++++-
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/matisse/src/main/java/com/zhihu/matisse/SelectionCreator.java b/matisse/src/main/java/com/zhihu/matisse/SelectionCreator.java
index 66aeadfe3..643ce7a05 100644
--- a/matisse/src/main/java/com/zhihu/matisse/SelectionCreator.java
+++ b/matisse/src/main/java/com/zhihu/matisse/SelectionCreator.java
@@ -343,6 +343,17 @@ public SelectionCreator setOnCheckedListener(@Nullable OnCheckedListener listene
         return this;
     }
 
+    /**
+     * Set if selection should change on case where maxSelectable is 1
+     * 
+     * @param changeSelectionOnSelectingOne
+     * @return {@link SelectionCreator} for fluent API. 
+     */
+    public SelectionCreator setChangeSelectionOnSelectingOne(boolean changeSelectionOnSelectingOne) {
+        mSelectionSpec.changeSelectionOnSelectingOne = changeSelectionOnSelectingOne;
+        return this;
+    }
+
     /**
      * Start to select media and wait for result.
      *
diff --git a/matisse/src/main/java/com/zhihu/matisse/internal/entity/SelectionSpec.java b/matisse/src/main/java/com/zhihu/matisse/internal/entity/SelectionSpec.java
index 80b7d1098..e0b244e81 100644
--- a/matisse/src/main/java/com/zhihu/matisse/internal/entity/SelectionSpec.java
+++ b/matisse/src/main/java/com/zhihu/matisse/internal/entity/SelectionSpec.java
@@ -57,6 +57,7 @@ public final class SelectionSpec {
     public int originalMaxSize;
     public OnCheckedListener onCheckedListener;
     public boolean showPreview;
+    public boolean changeSelectionOnSelectingOne;
 
     private SelectionSpec() {
     }
@@ -93,6 +94,7 @@ private void reset() {
         autoHideToobar = false;
         originalMaxSize = Integer.MAX_VALUE;
         showPreview = true;
+        changeSelectionOnSelectingOne = false;
     }
 
     public boolean singleSelectionModeEnabled() {
diff --git a/matisse/src/main/java/com/zhihu/matisse/internal/model/SelectedItemCollection.java b/matisse/src/main/java/com/zhihu/matisse/internal/model/SelectedItemCollection.java
index 7fdf69034..63186b102 100644
--- a/matisse/src/main/java/com/zhihu/matisse/internal/model/SelectedItemCollection.java
+++ b/matisse/src/main/java/com/zhihu/matisse/internal/model/SelectedItemCollection.java
@@ -167,7 +167,9 @@ public boolean isSelected(Item item) {
     }
 
     public IncapableCause isAcceptable(Item item) {
-        if (maxSelectableReached()) {
+        if (shouldRemoveSelection()) {
+            mItems.clear();
+        } else if (maxSelectableReached()) {
             int maxSelectable = currentMaxSelectable();
             String cause;
 
@@ -201,6 +203,11 @@ public boolean maxSelectableReached() {
         return mItems.size() == currentMaxSelectable();
     }
 
+    public boolean shouldRemoveSelection() {
+        SelectionSpec spec = SelectionSpec.getInstance();
+        return mItems.size() == 1 && currentMaxSelectable() == 1 && spec.changeSelectionOnSelectingOne;
+    }
+
     // depends
     private int currentMaxSelectable() {
         SelectionSpec spec = SelectionSpec.getInstance();