material-components / material-components/material-components-android
[com.google.android.material.appbar] HeaderScrollingViewBehavior.onMeasureChild
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Description
**Description:**
java.lang.NullPointerException - Attempt to read from field 'androidx.recyclerview.widget.ViewInfoStore androidx.recyclerview.widget.RecyclerView.mViewInfoStore' on a null object reference
**Expected behavior:** Screenshots and/or description of expected behavior
To appear the recycler view and the list of elements
**Source code:** The code snippet which is causing this issue
No reference to any class in my project in the stacktrace
```
Exception java.lang.NullPointerException: Attempt to read from field 'androidx.recyclerview.widget.ViewInfoStore androidx.recyclerview.widget.RecyclerView.mViewInfoStore' on a null object reference
at androidx.recyclerview.widget.RecyclerView$LayoutManager.addViewInt (RecyclerView.java:9402)
at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView (RecyclerView.java:9388)
at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView (RecyclerView.java:9375)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk (LinearLayoutManager.java:1676)
at androidx.recyclerview.widget.LinearLayoutManager.fill (LinearLayoutManager.java:1622)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren (LinearLayoutManager.java:687)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2 (RecyclerView.java:4645)
at androidx.recyclerview.widget.RecyclerView.onMeasure (RecyclerView.java:4022)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.LinearLayout.measureChildBeforeLayout (LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical (LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure (LinearLayout.java:721)
at android.view.View.measure (View.java:27131)
at androidx.core.widget.NestedScrollView.measureChildWithMargins (NestedScrollView.java:1792)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at androidx.core.widget.NestedScrollView.onMeasure (NestedScrollView.java:627)
at android.view.View.measure (View.java:27131)
at androidx.swiperefreshlayout.widget.SwipeRefreshLayout.onMeasure (SwipeRefreshLayout.java:641)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.LinearLayout.measureChildBeforeLayout (LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical (LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure (LinearLayout.java:721)
at android.view.View.measure (View.java:27131)
at android.widget.ScrollView.measureChildWithMargins (ScrollView.java:2362)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at android.widget.ScrollView.onMeasure (ScrollView.java:701)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.LinearLayout.measureChildBeforeLayout (LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical (LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure (LinearLayout.java:721)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onMeasureChild (CoordinatorLayout.java:760)
at com.google.android.material.appbar.HeaderScrollingViewBehavior.onMeasureChild (HeaderScrollingViewBehavior.java:99)
at com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior.onMeasureChild (AppBarLayout.java:2122)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onMeasure (CoordinatorLayout.java:831)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at androidx.appcompat.widget.ContentFrameLayout.onMeasure (ContentFrameLayout.java:145)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.LinearLayout.measureChildBeforeLayout (LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical (LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure (LinearLayout.java:721)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.LinearLayout.measureChildBeforeLayout (LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical (LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure (LinearLayout.java:721)
at android.view.View.measure (View.java:27131)
at android.view.ViewGroup.measureChildWithMargins (ViewGroup.java:7951)
at android.widget.FrameLayout.onMeasure (FrameLayout.java:194)
at com.android.internal.policy.DecorView.onMeasure (DecorView.java:1175)
at android.view.View.measure (View.java:27131)
at android.view.ViewRootImpl.performMeasure (ViewRootImpl.java:4187)
at android.view.ViewRootImpl.measureHierarchy (ViewRootImpl.java:2936)
at android.view.ViewRootImpl.performTraversals (ViewRootImpl.java:3204)
at android.view.ViewRootImpl.doTraversal (ViewRootImpl.java:2618)
at android.view.ViewRootImpl$TraversalRunnable.run (ViewRootImpl.java:9971)
at android.view.Choreographer$CallbackRecord.run (Choreographer.java:1010)
at android.view.Choreographer.doCallbacks (Choreographer.java:809)
at android.view.Choreographer.doFrame (Choreographer.java:744)
at android.view.Choreographer$FrameDisplayEventReceiver.run (Choreographer.java:995)
at android.os.Handler.handleCallback (Handler.java:938)
at android.os.Handler.dispatchMessage (Handler.java:99)
at android.os.Looper.loop (Looper.java:246)
at android.app.ActivityThread.main (ActivityThread.java:8653)
at java.lang.reflect.Method.invoke
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:602)
at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1130)
```
**Android API version:**
Several versions affected, from 25 to 34
**Material Library version:**
1.3.0
**Device:** Several devices: Huawey, Xaomi, Samsung...
To help us triage faster, please check to make sure you are using the [latest version](https://github.com/material-components/material-components-android/releases) of the library.
We also happily accept [pull requests](https://github.com/material-components/material-components-android/pulls).
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by examining HeaderScrollingViewBehavior.onMeasureChild and the RecyclerView LayoutManager.addViewInt stack-trace entries, using Material Library 1.3.0 as the reported baseline. Reproduce the failure with a minimal Android project across the affected API versions; done means the cause is isolated and a regression test or clearly validated fix prevents the null-pointer crash.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- android, java
- Domain
- mobile-dev
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100