Установите динамическую высоту макета в привязке данных

Question

Я хочу установить динамическую высоту макета в структуре привязки данных.

Я пытался что-то, но я получаю это исключение:

java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Integer.intValue()' on a null object reference 
        at databinding.ItemGroupCommentsBinding.executeBindings(ItemGroupCommentsBinding.java:147) 
        at android.databinding.ViewDataBinding.executePendingBindings(ViewDataBinding.java:355) 
        at view.base.adapter.DataBindingAdapter.onBindViewHolder(DataBindingAdapter.java:32) 
        at view.base.adapter.DataBindingAdapter.onBindViewHolder(DataBindingAdapter.java:15) 
        at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6279) 
        at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6312) 
        at android.support.v7.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5258) 
        at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5521) 
        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.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2141) 
        at android.support.v7.widget.GridLayoutManager.layoutChunk(GridLayoutManager.java:556) 
        at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1488) 
        at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:585) 
        at android.support.v7.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:170) 
        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:15604) 
        at android.view.ViewGroup.layout(ViewGroup.java:4966) 
        at android.support.v4.widget.SwipeRefreshLayout.onLayout(SwipeRefreshLayout.java:636) 
        at android.view.View.layout(View.java:15604) 
        at android.view.ViewGroup.layout(ViewGroup.java:4966) 
        at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1076) 
        at android.view.View.layout(View.java:15604) 
        at android.view.ViewGroup.layout(ViewGroup.java:4966) 
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573) 
        at android.widget.FrameLayout.onLayout(FrameLayout.java:508) 
        at android.view.View.layout(View.java:15604) 
        at android.view.ViewGroup.layout(ViewGroup.java:4966) 
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573) 
        at android.widget.FrameLayout.onLayout(FrameLayout.java:508) 
        at android.view.View.layout(View.java:15604) 
        at android.view.ViewGroup.layout(ViewGroup.java:4966) 
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703) 
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557) 
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1466) 
        at android.view.View.layout(View.java:15604) 
        at android.view.ViewGroup.layout(ViewGroup.java:4966) 
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573) 
        at android.widget.FrameLayout.onLayout(FrameLayout.java:508) 
        at android.view.View.layout(View.java:15604) 
        at android.view.ViewGroup.layout(ViewGroup.java:4966) 
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573) 
        at android.widget.FrameLayout.onLayout(FrameLayout.java:508) 
        at android.view.View.layout(View.java:15604) 
        at android.view.ViewGroup.layout(ViewGroup.java:4966) 
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703) 
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557) 
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1466) 
        at android.view.View.layout(View.java:15604) 
        at android.view.ViewGroup.layout(ViewGroup.java:4966) 
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573) 
        at android.widget.FrameLayout.onLayout(FrameLayout.java:508) 

Код является:

Fragment.java:

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    db = DataBindingUtil.inflate(inflater, R.layout.fragment_group_comments, container, false); 

    getSubComponent().inject(this); 

    db.setVariable(BR.height, 0); 

    // Inflate the layout for this fragment 
    return db.getRoot(); 
} 

@BindingAdapter("android:layout_height") 
public static void setLayoutHeight(View view, float commentNumber) { 
    Timber.e("setLayoutHeight " + commentNumber); 

    try { 
     GridLayoutManager.LayoutParams layoutParams = 
       (GridLayoutManager.LayoutParams) view.getLayoutParams(); 

     if (10 <= commentNumber && commentNumber < 10) { 
      layoutParams.height = 400; 
     } else if (11 <= commentNumber && commentNumber < 20) { 
      layoutParams.height = 500; 
     } 

     view.setLayoutParams(layoutParams); 
    } catch (Exception ignore) {} 
} 

item_.xml

<layout> 

<data> 

    <variable 
     name="height" 
     type="Integer" /> 
</data> 

<ScalingLayout 
    android:id="@+id/view_item" 
    style="@style/RelativeLayout_WrapContent" 
    android:layout_height="@{height, default=wrap_content}"> 

    <ImageView 
     style="@style/ImageView_WrapContent" 
     android:src="@mipmap/red_circle" /> 

</ScalingLayout> 
</layout> 

Answer 1

Вы должны изменить тип commentNumber от float к Integer или к int в вашем связывающим адаптер:

@BindingAdapter("android:layout_height") 
public static void setLayoutHeight(View view, Integer commentNumber) { 
    // your code staff   
} 

Проверить the example, где @BindingAdapter используется для настройки заполнения вида.