Leanback Sample-Aktivität stürzt ab

Question

Ich habe eine Lehnenteil-Beispielaktivität von Android Studio hinzugefügt. Die Aktivität stürzt mit folgendem Stacktrace ab. Ich habe den Code nicht geändert und ich sehe, dass alle Layouts, die standardmäßig hinzugefügt werden, die Parameter layout_width und layout_height definiert haben.

java.lang.RuntimeException: Binary XML file line #21: You must supply a layout_width attribute. 
    at android.content.res.TypedArray.getLayoutDimension(TypedArray.java:608) 
    at android.view.ViewGroup$LayoutParams.setBaseAttributes(ViewGroup.java:6485) 
    at android.view.ViewGroup$MarginLayoutParams.<init>(ViewGroup.java:6654) 
    at android.widget.FrameLayout$LayoutParams.<init>(FrameLayout.java:741) 
    at android.support.v17.leanback.widget.BaseCardView$LayoutParams.<init>(BaseCardView.java:862) 
    at android.support.v17.leanback.widget.BaseCardView.generateLayoutParams(BaseCardView.java:817) 
    at android.support.v17.leanback.widget.BaseCardView.generateLayoutParams(BaseCardView.java:54) 
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:812) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:483) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:415) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:365) 
    at android.support.v17.leanback.widget.ImageCardView.buildImageCardView(ImageCardView.java:165) 
    at android.support.v17.leanback.widget.ImageCardView.<init>(ImageCardView.java:156) 
    at android.support.v17.leanback.widget.ImageCardView.<init>(ImageCardView.java:282) 
    at android.support.v17.leanback.widget.ImageCardView.<init>(ImageCardView.java:275) 
    at com.amazon.bueller.photos.activity.CardPresenter$1.<init>(CardPresenter.java:55) 
    at com.amazon.bueller.photos.activity.CardPresenter.onCreateViewHolder(CardPresenter.java:55) 
    at android.support.v17.leanback.widget.ItemBridgeAdapter.onCreateViewHolder(ItemBridgeAdapter.java:312) 
    at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:6290) 
    at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5478) 
    at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5363) 
    at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5359) 
    at android.support.v17.leanback.widget.GridLayoutManager.measureScrapChild(GridLayoutManager.java:1211) 
    at android.support.v17.leanback.widget.GridLayoutManager.processRowSizeSecondary(GridLayoutManager.java:1277) 
    at android.support.v17.leanback.widget.GridLayoutManager.onMeasure(GridLayoutManager.java:1374) 
    at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:3012) 
    at android.view.View.measure(View.java:17935) 
    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5548) 
    at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
    at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
    at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
    at android.view.View.measure(View.java:17935) 
    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5548) 
    at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
    at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
    at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
    at android.view.View.measure(View.java:17935) 
    at android.support.v17.leanback.widget.GridLayoutManager.measureChild(GridLayoutManager.java:1466) 
    at android.support.v17.leanback.widget.GridLayoutManager$2.createItem(GridLayoutManager.java:1556) 
    at android.support.v17.leanback.widget.SingleRow.appendVisibleItems(SingleRow.java:111) 
    at android.support.v17.leanback.widget.Grid.appendVisibleItems(Grid.java:371) 
    at android.support.v17.leanback.widget.GridLayoutManager.appendVisibleItems(GridLayoutManager.java:1749) 
    at android.support.v17.leanback.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:1973) 
    at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3506) 
    at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3254) 
    at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3767) 
    at android.view.View.layout(View.java:16046) 
                     at android.view.ViewGroup.layout 

Answer 1

'Theme.Leanback' als Stil zur Aktivität hinzufügen und der Fehler verschwindet.

Beispiel:

<activity android:name="com.sample.activity.DetailsActivity" 
       android:theme="@style/Theme.Leanback"/>