Android 在数据绑定中设置动态布局高度

我想在数据绑定结构中设置动态布局高度

我尝试了一些东西，但我得到了一个例外：

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)

代码是：

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) {}
}

@覆盖
创建视图上的公共视图（布局、充气机、视图组容器、，
Bundle savedInstanceState）{
db=DataBindingUtil.inflate（充气器，R.layout.fragment\u group\u注释，容器，false）；
getSubComponent（）.inject（此）；
db.setVariable（BR.height，0）；
//为该碎片膨胀布局
返回db.getRoot（）；
}
@BindingAdapter（“安卓：布局高度”）
公共静态void setLayouthweight（视图、浮点注释编号）{
木材.e（“SetLayouthweight”+编号）；
试一试{
GridLayoutManager.LayoutParams LayoutParams=
（GridLayoutManager.LayoutParams）view.getLayoutParams（）；
如果（10您需要在绑定适配器中将
commentNumber
类型从
float
更改为
Integer
或更改为
int
：

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

检查，其中
@BindingAdapter
用于设置视图的填充。
这里有一个示例
BindingAdapter
，它可以动态设置视图的高度。它使用两种不同的
布局参数
类型。如果缺少所需的类型，只需在
选项时将其添加为下一个

import org.jetbrains.anko.dip

/**
 * Set the view's height using Android Binding adapter
 *
 * Usage:
 *  <LinearLayout
 *     android:layout_width="match_parent"
 *     android:layout_height="wrap_content"
 *     app:dynamicHeight="@{viewModel.myCustomHeight}" />
 *
 * @param  dpHeight  height in density-independent pixels [ObservableInt].
 * @author Bartosz Kosarzycki
 */
@BindingAdapter("dynamicHeight")
fun View.setDynamicHeight(dpHeight: ObservableInt) {
    val pxHeight = dip(dpHeight.get())
    when (this.layoutParams) {
        is LinearLayout.LayoutParams ->
            this.layoutParams = LinearLayout.LayoutParams(layoutParams.width, pxHeight)
        is RelativeLayout.LayoutParams ->
            this.layoutParams = RelativeLayout.LayoutParams(layoutParams.width, pxHeight)
        is ViewGroup.LayoutParams ->
            this.layoutParams = ViewGroup.LayoutParams(layoutParams.width, pxHeight)
        else -> throw RuntimeException("No such view type in 'dynamicHeight' binding adapter")
    }
}

import org.jetbrains.anko.dip
/**
*使用Android绑定适配器设置视图的高度
*
*用法：
*  
*
*@param dpHeight高度（以密度无关的像素为单位）[可观察]。
*@作者Bartosz Kosarzycki
*/
@BindingAdapter（“动态灯光”）
有趣的视图。设置动态灯光（dpHeight:ObservableInt）{
val pxHeight=dip（dpHeight.get（））
何时（this.layoutParams）{
是LinearLayout.LayoutParams->
this.layoutParams=LinearLayout.layoutParams（layoutParams.width，pxHeight）
是RelativeLayout.LayoutParams->
this.layoutParams=RelativeLayout.layoutParams（layoutParams.width，pxHeight）
是ViewGroup.LayoutParams->
this.layoutParams=ViewGroup.layoutParams（layoutParams.width，pxHeight）
else->throw RuntimeException（“dynamicHeight”绑定适配器中没有此类视图类型”）
}
}
当布局xml的数据绑定初始化时，您何时调用了
setLayouthweight
方法？@Huy Towerin
onCreateView
。现在一切正常。谢谢。
import org.jetbrains.anko.dip

/**
 * Set the view's height using Android Binding adapter
 *
 * Usage:
 *  <LinearLayout
 *     android:layout_width="match_parent"
 *     android:layout_height="wrap_content"
 *     app:dynamicHeight="@{viewModel.myCustomHeight}" />
 *
 * @param  dpHeight  height in density-independent pixels [ObservableInt].
 * @author Bartosz Kosarzycki
 */
@BindingAdapter("dynamicHeight")
fun View.setDynamicHeight(dpHeight: ObservableInt) {
    val pxHeight = dip(dpHeight.get())
    when (this.layoutParams) {
        is LinearLayout.LayoutParams ->
            this.layoutParams = LinearLayout.LayoutParams(layoutParams.width, pxHeight)
        is RelativeLayout.LayoutParams ->
            this.layoutParams = RelativeLayout.LayoutParams(layoutParams.width, pxHeight)
        is ViewGroup.LayoutParams ->
            this.layoutParams = ViewGroup.LayoutParams(layoutParams.width, pxHeight)
        else -> throw RuntimeException("No such view type in 'dynamicHeight' binding adapter")
    }
}