Crash when adding multiple attachments to Deck card – IllegalStateException: Two different ViewHolders have the same stable ID

[meeoeen]

This issue respects the following points:

• I have read the FAQ
• I have searched for existing issues
• The issue affects the Deck Android app, neither the Deck server app nor the Nextcloud Android app.

Describe the bug

Hi 👋

A user of the Nextcloud Deck Android app is experiencing a crash when adding multiple attachments (images) to a card.

Context: The crash occurs immediately after adding the attachments to a Deck card. It seems that multiple items in the RecyclerView are assigned the same ID (-1), which leads to a collision and a crash.

Steps to reproduce:

1. Open/create a card
2. Click on Attachments tab
3. Click upload
4. Select gallery
5. Add multiple pictures (long click on one pic then short click on more pics)
6. Validate
7. The IllegalStateException is thrown
8. Attachments are added randomly - sometimes the last selected picture is added twice, sometimes some of the attachments are missing.

Suggestion: Maybe ensure that each attachment item in the adapter (CardAttachmentAdapter) has a unique stable ID, even if it hasn't yet been persisted to the server.

Expected behavior

No exception is thrown, and each pic is added once and only once as attachment to the card.

Deck Android version

1.24.5 (F-Droid)

Deck server version

1.15.2

Nextcloud Android version

3.32.2

Nextcloud version

31.0.7

Device

Samsung Galaxy S10+ (SM-G975U1)

Android Version

12

App Store

• Google Play Store
• Google Play Store (Beta channel)
• F-Droid
• Huawei App Gallery

Stacktrace

Full Crash:

App Version: 1.24.5
App Version Code: 1024005
App Flavor: fdroid

Files App Version Code: 30320290 ([com.nextcloud.android.sso.model.FilesAppType@dcba210](mailto:com.nextcloud.android.sso.model.FilesAppType@dcba210))

---

OS Version: 4.14.190-25741239-abG975U1UEU9IXE1(G975U1UEU9IXE1)
OS API Level: 31
Device: beyond2q
Manufacturer: samsung
Model (and Product): SM-G975U1 (beyond2qlteue)

---

java.lang.IllegalStateException: Two different ViewHolders have the same stable ID. Stable IDs in your adapter MUST BE unique and SHOULD NOT change.
 ViewHolder 1:ImageAttachmentViewHolder{241323 position=1 id=-1, oldPos=-1, pLpos:-1 not recyclable(1)} 
 View Holder 2:ImageAttachmentViewHolder{68f5452 position=0 id=-1, oldPos=-1, pLpos:-1} androidx.recyclerview.widget.RecyclerView{450131a VFED.V... ......ID 0,0-1080,1718 #7f0a0083 app:id/attachments_list}, adapter:it.niedermann.nextcloud.deck.ui.card.attachments.CardAttachmentAdapter@3c4e96b, layout:androidx.recyclerview.widget.GridLayoutManager@db82cc8, context:it.niedermann.nextcloud.deck.ui.card.EditActivity@738a980
at androidx.recyclerview.widget.RecyclerView.handleMissingPreInfoForChangeError(RecyclerView.java:4268)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep3(RecyclerView.java:4192)
at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3862)
at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4404)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at androidx.coordinatorlayout.widget.CoordinatorLayout.layoutChild(CoordinatorLayout.java:1213)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onLayoutChild(CoordinatorLayout.java:899)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:919)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:374)
at android.widget.FrameLayout.onLayout(FrameLayout.java:312)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at androidx.recyclerview.widget.RecyclerView$LayoutManager.layoutDecoratedWithMargins(RecyclerView.java:9587)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1685)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4134)
at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3851)
at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4404)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at androidx.viewpager2.widget.ViewPager2.onLayout(ViewPager2.java:527)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at com.google.android.material.appbar.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:149)
at com.google.android.material.appbar.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:43)
at com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior.onLayoutChild(AppBarLayout.java:2365)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:918)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:374)
at android.widget.FrameLayout.onLayout(FrameLayout.java:312)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:374)
at android.widget.FrameLayout.onLayout(FrameLayout.java:312)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:374)
at android.widget.FrameLayout.onLayout(FrameLayout.java:312)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:1330)
at android.view.View.layout(View.java:24461)
at android.view.ViewGroup.layout(ViewGroup.java:7412)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:4609)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:4031)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:2919)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:10491)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1108)
at android.view.Choreographer.doCallbacks(Choreographer.java:866)
at android.view.Choreographer.doFrame(Choreographer.java:797)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1092)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:226)
at android.os.Looper.loop(Looper.java:313)
at android.app.ActivityThread.main(ActivityThread.java:8663)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:567)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1135)

[m4nges]

I also experience this crash under similar conditions.
Here are the details from my case:

App and environment

Deck Android app: 1.24.5 (F-Droid)

Device: Google Pixel 6 Pro (raven)

Android: 14 / API 36

Server/Deck versions not relevant to crash (it happens locally in the app)

Reproduction steps

Open an existing card

Tap “Add attachment”

Select multiple items at once (gallery or file picker)

Confirm selection → app crashes immediately

Crash details
The stacktrace shows the same error from the existing report:
java.lang.IllegalStateException: Two different ViewHolders have the same stable ID

This suggests that multiple new attachments get a default ID (e.g. -1), causing a conflict in the adapter.

Workaround I use:
Adding attachments one at a time avoids the crash.

Thank you!