Merge pull request #164 from yuyakaido/issue/153

Fix crash when recreating holder activity
yuyakaido · Dec 12, 2018 · 7f60c99 · 7f60c99
2 parents 34597ac + 03329b2
commit 7f60c99
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Showing 2 changed files with 68 additions and 44 deletions.
diff --git a/cardstackview/src/main/java/com/yuyakaido/android/cardstackview/CardStackView.java b/cardstackview/src/main/java/com/yuyakaido/android/cardstackview/CardStackView.java
@@ -6,53 +6,12 @@
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 
+import com.yuyakaido.android.cardstackview.internal.CardStackDataObserver;
 import com.yuyakaido.android.cardstackview.internal.CardStackSnapHelper;
 
 public class CardStackView extends RecyclerView {
 
-    private final AdapterDataObserver observer = new AdapterDataObserver() {
-        private CardStackLayoutManager getCardStackLayoutManager() {
-            LayoutManager manager = getLayoutManager();
-            if (manager instanceof CardStackLayoutManager) {
-                return (CardStackLayoutManager) manager;
-            }
-            throw new IllegalStateException("CardStackView must be set CardStackLayoutManager.");
-        }
-        @Override
-        public void onChanged() {
-            CardStackLayoutManager manager = getCardStackLayoutManager();
-            manager.setTopPosition(0);
-        }
-
-        @Override
-        public void onItemRangeChanged(int positionStart, int itemCount) {
-            // Do nothing
-        }
-
-        @Override
-        public void onItemRangeChanged(int positionStart, int itemCount, @Nullable Object payload) {
-            // Do nothing
-        }
-
-        @Override
-        public void onItemRangeInserted(int positionStart, int itemCount) {
-            // Do nothing
-        }
-
-        @Override
-        public void onItemRangeRemoved(int positionStart, int itemCount) {
-            CardStackLayoutManager manager = getCardStackLayoutManager();
-            if (positionStart == 0) {
-                manager.setTopPosition(0);
-            }
-            manager.removeAllViews();
-        }
-
-        @Override
-        public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
-            // Do nothing
-        }
-    };
+    private final CardStackDataObserver observer = new CardStackDataObserver(this);
 
     public CardStackView(Context context) {
         this(context, null);
@@ -90,6 +49,7 @@ protected void onAttachedToWindow() {
         RecyclerView.Adapter adapter = getAdapter();
         if (adapter != null) {
             adapter.registerAdapterDataObserver(observer);
+            observer.isRegistered = true;
         }
     }
 
@@ -98,7 +58,10 @@ protected void onDetachedFromWindow() {
         super.onDetachedFromWindow();
         RecyclerView.Adapter adapter = getAdapter();
         if (adapter != null) {
-            adapter.unregisterAdapterDataObserver(observer);
+            if (observer.isRegistered) {
+                adapter.unregisterAdapterDataObserver(observer);
+                observer.isRegistered = false;
+            }
         }
     }
 

diff --git a/...iew/src/main/java/com/yuyakaido/android/cardstackview/internal/CardStackDataObserver.java b/...iew/src/main/java/com/yuyakaido/android/cardstackview/internal/CardStackDataObserver.java
@@ -0,0 +1,61 @@
+package com.yuyakaido.android.cardstackview.internal;
+
+import android.support.annotation.Nullable;
+import android.support.v7.widget.RecyclerView;
+
+import com.yuyakaido.android.cardstackview.CardStackLayoutManager;
+
+public class CardStackDataObserver extends RecyclerView.AdapterDataObserver {
+
+    public boolean isRegistered = false;
+
+    private final RecyclerView recyclerView;
+
+    public CardStackDataObserver(RecyclerView recyclerView) {
+        this.recyclerView = recyclerView;
+    }
+
+    @Override
+    public void onChanged() {
+        CardStackLayoutManager manager = getCardStackLayoutManager();
+        manager.setTopPosition(0);
+    }
+
+    @Override
+    public void onItemRangeChanged(int positionStart, int itemCount) {
+        // Do nothing
+    }
+
+    @Override
+    public void onItemRangeChanged(int positionStart, int itemCount, @Nullable Object payload) {
+        // Do nothing
+    }
+
+    @Override
+    public void onItemRangeInserted(int positionStart, int itemCount) {
+        // Do nothing
+    }
+
+    @Override
+    public void onItemRangeRemoved(int positionStart, int itemCount) {
+        CardStackLayoutManager manager = getCardStackLayoutManager();
+        if (positionStart == 0) {
+            manager.setTopPosition(0);
+        }
+        manager.removeAllViews();
+    }
+
+    @Override
+    public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
+        // Do nothing
+    }
+
+    private CardStackLayoutManager getCardStackLayoutManager() {
+        RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
+        if (manager instanceof CardStackLayoutManager) {
+            return (CardStackLayoutManager) manager;
+        }
+        throw new IllegalStateException("CardStackView must be set CardStackLayoutManager.");
+    }
+
+}