我想在数据绑定结构中设置动态布局高度。
我试了一下,但我得到了这个例外:
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) {}
}
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>
您需要将commentNumber
类型从float
更改为Integer
或更改为绑定适配器中的int
:
@BindingAdapter("android:layout_height")
public static void setLayoutHeight(View view, Integer commentNumber) {
// your code staff
}
检查the example,其中@BindingAdapter
用于设置视图的填充。
这里有一个BindingAdapter
示例,可以动态设置View的高度。它使用了几种不同的LayoutParams
类型。如果您需要的那个丢失了 - 只需将其添加为下一个when
选项。
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")
}
}