296

我习惯于在没有数据时显示的文档中描述ListActivity的布局文件中放置一个特殊视图。此视图具有 id 。"android:id/empty"

<TextView
    android:id="@android:id/empty"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/no_data" />

我想知道新的如何做到这一点RecyclerView？

4

15 回答 15

337

在定义 的同一布局上RecyclerView，添加TextView：

<android.support.v7.widget.RecyclerView
    android:id="@+id/recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:scrollbars="vertical" />

<TextView
    android:id="@+id/empty_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:visibility="gone"
    android:text="@string/no_data_available" />

在onCreate或适当的回调中，您检查提供给您的数据集是否RecyclerView为空。如果数据集为空，则RecyclerView也为空。在这种情况下，消息会出现在屏幕上。如果没有，请更改其可见性：

private RecyclerView recyclerView;
private TextView emptyView;

// ...

recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
emptyView = (TextView) rootView.findViewById(R.id.empty_view);

// ...

if (dataset.isEmpty()) {
    recyclerView.setVisibility(View.GONE);
    emptyView.setVisibility(View.VISIBLE);
}
else {
    recyclerView.setVisibility(View.VISIBLE);
    emptyView.setVisibility(View.GONE);
}
于 2015-02-05T19:16:13.600 回答
200

对于我的项目，我提出了这个解决方案（RecyclerView使用setEmptyView方法）：

public class RecyclerViewEmptySupport extends RecyclerView {
    private View emptyView;

    private AdapterDataObserver emptyObserver = new AdapterDataObserver() {


        @Override
        public void onChanged() {
            Adapter<?> adapter =  getAdapter();
            if(adapter != null && emptyView != null) {
                if(adapter.getItemCount() == 0) {
                    emptyView.setVisibility(View.VISIBLE);
                    RecyclerViewEmptySupport.this.setVisibility(View.GONE);
                }
                else {
                    emptyView.setVisibility(View.GONE);
                    RecyclerViewEmptySupport.this.setVisibility(View.VISIBLE);
                }
            }

        }
    };

    public RecyclerViewEmptySupport(Context context) {
        super(context);
    }

    public RecyclerViewEmptySupport(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public RecyclerViewEmptySupport(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public void setAdapter(Adapter adapter) {
        super.setAdapter(adapter);

        if(adapter != null) {
            adapter.registerAdapterDataObserver(emptyObserver);
        }

        emptyObserver.onChanged();
    }

    public void setEmptyView(View emptyView) {
        this.emptyView = emptyView;
    }
}

你应该使用它而不是RecyclerView类：

<com.maff.utils.RecyclerViewEmptySupport android:id="@+id/list1"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    />

<TextView android:id="@+id/list_empty"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Empty"
    />

和

RecyclerViewEmptySupport list = 
    (RecyclerViewEmptySupport)rootView.findViewById(R.id.list1);
list.setLayoutManager(new LinearLayoutManager(context));
list.setEmptyView(rootView.findViewById(R.id.list_empty));
于 2015-05-23T17:22:41.907 回答
70

这是一个解决方案，仅使用具有不同视图类型的自定义适配器来处理空情况。

public class EventAdapter extends 
    RecyclerView.Adapter<EventAdapter.ViewHolder> {

    private static final int VIEW_TYPE_EVENT = 0;
    private static final int VIEW_TYPE_DATE = 1;
    private static final int VIEW_TYPE_EMPTY = 2;

    private ArrayList items;

    public EventAdapter(ArrayList items) {
        this.items = items;
    }

    @Override
    public int getItemCount() {
        if(items.size() == 0){
            return 1;
        }else {
            return items.size();
        }
    }

    @Override
    public int getItemViewType(int position) {
        if (items.size() == 0) {
            return VIEW_TYPE_EMPTY;
        }else{
            Object item = items.get(position);
            if (item instanceof Event) {
                return VIEW_TYPE_EVENT;
            } else {
                return VIEW_TYPE_DATE;
            }
        }
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v;
        ViewHolder vh;
        if (viewType == VIEW_TYPE_EVENT) {
            v = LayoutInflater.from(parent.getContext()).inflate(
                R.layout.item_event, parent, false);
            vh = new ViewHolderEvent(v);
        } else if (viewType == VIEW_TYPE_DATE) {
            v = LayoutInflater.from(parent.getContext()).inflate(
                R.layout.item_event_date, parent, false);
            vh = new ViewHolderDate(v);
        } else {
            v = LayoutInflater.from(parent.getContext()).inflate(
                R.layout.item_event_empty, parent, false);
            vh = new ViewHolder(v);
        }

        return vh;
    }

    @Override
    public void onBindViewHolder(EventAdapter.ViewHolder viewHolder, 
                                 final int position) {
        int viewType = getItemViewType(position);
        if (viewType == VIEW_TYPE_EVENT) {
            //...
        } else if (viewType == VIEW_TYPE_DATE) {
            //...
        } else if (viewType == VIEW_TYPE_EMPTY) {
            //...
        }
    }

    public static class ViewHolder extends ParentViewHolder {
        public ViewHolder(View v) {
            super(v);
        }
    }

    public static class ViewHolderDate extends ViewHolder {
        public ViewHolderDate(View v) {
            super(v);
        }
    }

    public static class ViewHolderEvent extends ViewHolder {
        public ViewHolderEvent(View v) {
            super(v);
        }
    }

}
于 2016-03-07T15:05:43.207 回答
53

我使用 ViewSwitcher

<ViewSwitcher
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/switcher"
    >

    <android.support.v7.widget.RecyclerView
        android:id="@+id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

    <TextView android:id="@+id/text_empty"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/list_empty"
        android:gravity="center"
        />

</ViewSwitcher>

在代码中，您将检查光标/数据集并切换视图。

void showItems(Cursor items) {
    if (items.size() > 0) {

        mAdapter.switchCursor(items);

        if (R.id.list == mListSwitcher.getNextView().getId()) {
            mListSwitcher.showNext();
        }
    } else if (R.id.text_empty == mListSwitcher.getNextView().getId()) {
        mListSwitcher.showNext();
    }
}

如果您愿意，也可以使用几行代码设置动画

mListSwitcher.setInAnimation(slide_in_left);
mListSwitcher.setOutAnimation(slide_out_right);
于 2015-10-14T17:22:19.277 回答
47

由于凯文的回答并不完整。
如果您使用RecyclerAdapter'snotifyItemInserted和notifyItemRemoved更新数据集，这是更正确的答案。请参阅下面另一个用户添加的 Kotlin 版本。

爪哇：

mAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {

    @Override
    public void onChanged() {
        super.onChanged();
        checkEmpty();
    }

    @Override
    public void onItemRangeInserted(int positionStart, int itemCount) {
        super.onItemRangeInserted(positionStart, itemCount);
        checkEmpty();
    }

    @Override
    public void onItemRangeRemoved(int positionStart, int itemCount) {
        super.onItemRangeRemoved(positionStart, itemCount);
        checkEmpty();
    }

    void checkEmpty() {
        mEmptyView.setVisibility(mAdapter.getItemCount() == 0 ? View.VISIBLE : View.GONE);
    }
});

科特林 

adapter.registerAdapterDataObserver(object : RecyclerView.AdapterDataObserver() {
    override fun onChanged() {
        super.onChanged()
        checkEmpty()
    }

    override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
        super.onItemRangeInserted(positionStart, itemCount)
        checkEmpty()
    }

    override fun onItemRangeRemoved(positionStart: Int, itemCount: Int) {
        super.onItemRangeRemoved(positionStart, itemCount)
        checkEmpty()
    }

    fun checkEmpty() {
        empty_view.visibility = (if (adapter.itemCount == 0) View.VISIBLE else View.GONE)
    }
})
于 2018-01-01T11:07:29.827 回答
21

RVEmptyObserver

不是使用 custom RecyclerView，而是扩展 anAdapterDataObserver是一种更简单的解决方案，它允许设置View在列表中没有项目时显示的自定义：

示例用法：

RVEmptyObserver observer = new RVEmptyObserver(recyclerView, emptyView)
rvAdapter.registerAdapterDataObserver(observer);

班级：

public class RVEmptyObserver extends RecyclerView.AdapterDataObserver {
    private View emptyView;
    private RecyclerView recyclerView;

    public RVEmptyObserver(RecyclerView rv, View ev) {
        this.recyclerView = rv;
        this.emptyView    = ev;
        checkIfEmpty();
    }

    private void checkIfEmpty() {
        if (emptyView != null && recyclerView.getAdapter() != null) {
            boolean emptyViewVisible = recyclerView.getAdapter().getItemCount() == 0;
            emptyView.setVisibility(emptyViewVisible ? View.VISIBLE : View.GONE);
            recyclerView.setVisibility(emptyViewVisible ? View.GONE : View.VISIBLE);
        }
    }

    public void onChanged() { checkIfEmpty(); }
    public void onItemRangeInserted(int positionStart, int itemCount) { checkIfEmpty(); }
    public void onItemRangeRemoved(int positionStart, int itemCount) { checkIfEmpty(); }
}
于 2017-05-13T13:18:25.110 回答
9

在您的适配器上getItemViewType检查适配器是否有 0 个元素，如果有，则返回不同的 viewType。

然后在您onCreateViewHolder检查 viewType 是否是您之前返回的那个并膨胀不同的视图。在这种情况下，带有该 TextView 的布局文件

编辑

如果这仍然不起作用，那么您可能希望像这样以编程方式设置视图的大小：

Point size = new Point();
((WindowManager)itemView.getContext().getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay().getSize(size);

然后当你膨胀你的视图调用时：

inflatedView.getLayoutParams().height = size.y;
inflatedView.getLayoutParams().width = size.x;
于 2015-01-29T14:48:29.910 回答
9

这是我的显示空视图、重试视图（加载 api 失败时）和加载进度的类RecyclerView

public class RecyclerViewEmptyRetryGroup extends RelativeLayout {
    private RecyclerView mRecyclerView;
    private LinearLayout mEmptyView;
    private LinearLayout mRetryView;
    private ProgressBar mProgressBar;
    private OnRetryClick mOnRetryClick;

    public RecyclerViewEmptyRetryGroup(Context context) {
        this(context, null);
    }

    public RecyclerViewEmptyRetryGroup(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public RecyclerViewEmptyRetryGroup(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    public void onViewAdded(View child) {
        super.onViewAdded(child);
        if (child.getId() == R.id.recyclerView) {
            mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
            return;
        }
        if (child.getId() == R.id.layout_empty) {
            mEmptyView = (LinearLayout) findViewById(R.id.layout_empty);
            return;
        }
        if (child.getId() == R.id.layout_retry) {
            mRetryView = (LinearLayout) findViewById(R.id.layout_retry);
            mRetryView.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    mRetryView.setVisibility(View.GONE);
                    mOnRetryClick.onRetry();
                }
            });
            return;
        }
        if (child.getId() == R.id.progress_bar) {
            mProgressBar = (ProgressBar) findViewById(R.id.progress_bar);
        }
    }

    public void loading() {
        mRetryView.setVisibility(View.GONE);
        mEmptyView.setVisibility(View.GONE);
        mProgressBar.setVisibility(View.VISIBLE);
    }

    public void empty() {
        mEmptyView.setVisibility(View.VISIBLE);
        mRetryView.setVisibility(View.GONE);
        mProgressBar.setVisibility(View.GONE);
    }

    public void retry() {
        mRetryView.setVisibility(View.VISIBLE);
        mEmptyView.setVisibility(View.GONE);
        mProgressBar.setVisibility(View.GONE);
    }

    public void success() {
        mRetryView.setVisibility(View.GONE);
        mEmptyView.setVisibility(View.GONE);
        mProgressBar.setVisibility(View.GONE);
    }

    public RecyclerView getRecyclerView() {
        return mRecyclerView;
    }

    public void setOnRetryClick(OnRetryClick onRetryClick) {
        mOnRetryClick = onRetryClick;
    }

    public interface OnRetryClick {
        void onRetry();
    }
}

活动_xml

<...RecyclerViewEmptyRetryGroup
        android:id="@+id/recyclerViewEmptyRetryGroup">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recyclerView"/>

        <LinearLayout
            android:id="@+id/layout_empty">
            ...
        </LinearLayout>

        <LinearLayout
            android:id="@+id/layout_retry">
            ...
        </LinearLayout>

        <ProgressBar
            android:id="@+id/progress_bar"/>

</...RecyclerViewEmptyRetryGroup>

在此处输入图像描述

来源在这里https://github.com/PhanVanLinh/AndroidRecyclerViewWithLoadingEmptyAndRetry

于 2017-07-14T10:29:28.400 回答
9

在自定义 RecyclerView 中使用 AdapterDataObserver

科特林：

RecyclerViewEnum.kt

enum class RecyclerViewEnum {
    LOADING,
    NORMAL,
    EMPTY_STATE
}

RecyclerViewEmptyLoadingSupport.kt

class RecyclerViewEmptyLoadingSupport : RecyclerView {

    var stateView: RecyclerViewEnum? = RecyclerViewEnum.LOADING
        set(value) {
            field = value
            setState()
        }
    var emptyStateView: View? = null
    var loadingStateView: View? = null


    constructor(context: Context) : super(context) {}

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {}

    constructor(context: Context, attrs: AttributeSet, defStyle: Int) : super(context, attrs, defStyle) {}


    private val dataObserver = object : AdapterDataObserver() {
        override fun onChanged() {
            onChangeState()
        }

        override fun onItemRangeRemoved(positionStart: Int, itemCount: Int) {
            super.onItemRangeRemoved(positionStart, itemCount)
            onChangeState()
        }

        override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
            super.onItemRangeInserted(positionStart, itemCount)
            onChangeState()
        }
    }


    override fun setAdapter(adapter: RecyclerView.Adapter<*>?) {
        super.setAdapter(adapter)
        adapter?.registerAdapterDataObserver(dataObserver)
        dataObserver.onChanged()
    }


    fun onChangeState() {
        if (adapter?.itemCount == 0) {
            emptyStateView?.visibility = View.VISIBLE
            loadingStateView?.visibility = View.GONE
            this@RecyclerViewEmptyLoadingSupport.visibility = View.GONE
        } else {
            emptyStateView?.visibility = View.GONE
            loadingStateView?.visibility = View.GONE
            this@RecyclerViewEmptyLoadingSupport.visibility = View.VISIBLE
        }
    }

    private fun setState() {

        when (this.stateView) {
            RecyclerViewEnum.LOADING -> {
                loadingStateView?.visibility = View.VISIBLE
                this@RecyclerViewEmptyLoadingSupport.visibility = View.GONE
                emptyStateView?.visibility = View.GONE
            }

            RecyclerViewEnum.NORMAL -> {
                loadingStateView?.visibility = View.GONE
                this@RecyclerViewEmptyLoadingSupport.visibility = View.VISIBLE
                emptyStateView?.visibility = View.GONE
            }
            RecyclerViewEnum.EMPTY_STATE -> {
                loadingStateView?.visibility = View.GONE
                this@RecyclerViewEmptyLoadingSupport.visibility = View.GONE
                emptyStateView?.visibility = View.VISIBLE
            }
        }
    }
}

布局.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <LinearLayout
        android:id="@+id/emptyView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/white"
        android:gravity="center"
        android:orientation="vertical">

        <TextView
            android:id="@+id/emptyLabelTv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="empty" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/loadingView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/white"
        android:gravity="center"
        android:orientation="vertical">

        <ProgressBar
            android:id="@+id/progressBar"
            android:layout_width="45dp"
            android:layout_height="45dp"
            android:layout_gravity="center"
            android:indeterminate="true"
            android:theme="@style/progressBarBlue" />
    </LinearLayout>

    <com.peeyade.components.recyclerView.RecyclerViewEmptyLoadingSupport
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

在活动中使用这种方式：

recyclerView?.apply {
        layoutManager = GridLayoutManager(context, 2)
        emptyStateView = emptyView
        loadingStateView = loadingView
        adapter = adapterGrid
    }

    // you can set LoadingView or emptyView manual
    recyclerView.stateView = RecyclerViewEnum.EMPTY_STATE
    recyclerView.stateView = RecyclerViewEnum.LOADING
于 2018-10-09T08:42:09.727 回答
2

我添加和RecyclerView替代ImageView：RelativeLayout

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/no_active_jobs"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="@mipmap/ic_active_jobs" />

    <android.support.v7.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

然后在Adapter：

@Override
public int getItemCount() {
    if (mOrders.size() == 0) {
        mRecyclerView.setVisibility(View.INVISIBLE);
    } else {
        mRecyclerView.setVisibility(View.VISIBLE);
    }
    return mOrders.size();
}
于 2016-01-29T14:41:59.823 回答
2

addOnChildAttachStateChangeListener另一种方法是使用RecyclerView.

recyclerView.addOnChildAttachStateChangeListener(new RecyclerView.OnChildAttachStateChangeListener() {
            @Override
            public void onChildViewAttachedToWindow(@NonNull View view) {
                forEmptyTextView.setVisibility(View.INVISIBLE);
            }

            @Override
            public void onChildViewDetachedFromWindow(@NonNull View view) {
                forEmptyTextView.setVisibility(View.VISIBLE);
            }
        });
于 2019-10-21T18:52:04.463 回答
1

最简单的解决方案是使用RecyclerView.AdapterDataObserver并在您的适配器初始化后将其注册到您的recyclerview中。

val emptyDataObserver = EmptyDataObserver(recycler_view, empty_data_parent)
yourAdapter.registerAdapterDataObserver(emptyDataObserver)

其中， recycler_view 和 empty_data_parent 是您活动中的布局，根据需要限制这些视图并使其可见性GONE。然后使用图像和文本创建您自己的空数据集视图。

 <include
            android:id="@+id/empty_data_parent"
            layout="@layout/item_empty_dataset"
            android:layout_width="match_parent"
            android:visibility="gone"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintTop_toBottomOf="parent"
            android:layout_height="match_parent"
            android:layout_gravity="center" />

这是empty_data_set_view.xml的示例

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:layout_gravity="center"
    android:gravity="center"
    android:paddingTop="10dp"
    android:paddingBottom="10dp"
    tools:ignore="RtlHardcoded">

    <ImageView
        android:id="@+id/imageView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.422"
        android:src="@drawable/ic_empty_dataset_1" />

    <TextView
        android:id="@+id/title"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="Title is called when title is placed"
        android:padding="10dp"
        android:fontFamily="@font/normal"
        android:textStyle="bold"
        android:gravity="center"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView2" />

    <TextView
        android:id="@+id/sub_title"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text=" Subtitle is called when title is placed. Subtitle is called when title is placed"
        android:padding="5dp"
        android:fontFamily="@font/normal"
        android:gravity="center"
        android:layout_marginStart="10dp"
        android:layout_marginEnd="10dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/title" />
</androidx.constraintlayout.widget.ConstraintLayout>

这个EmptyDataObserver类将完成这项工作。

import android.view.View
import androidx.recyclerview.widget.RecyclerView


class EmptyDataObserver constructor(rv: RecyclerView?, ev: View?): RecyclerView.AdapterDataObserver() {

    private var emptyView: View? = null
    private var recyclerView: RecyclerView? = null

    init {
        recyclerView = rv
        emptyView = ev
        checkIfEmpty()
    }


    private fun checkIfEmpty() {
        if (emptyView != null && recyclerView!!.adapter != null) {
            val emptyViewVisible = recyclerView!!.adapter!!.itemCount == 0
            emptyView!!.visibility = if (emptyViewVisible) View.VISIBLE else View.GONE
            recyclerView!!.visibility = if (emptyViewVisible) View.GONE else View.VISIBLE
        }
    }

    override fun onChanged() {
        super.onChanged()
        checkIfEmpty()
    }

    override fun onItemRangeChanged(positionStart: Int, itemCount: Int) {
        super.onItemRangeChanged(positionStart, itemCount)
    }

}
于 2021-05-03T14:57:36.820 回答
0

以防您正在使用 FirebaseRecyclerAdapter，这篇文章很有魅力https://stackoverflow.com/a/39058636/6507009

于 2017-07-21T14:17:02.833 回答
0

如果您想在回收站视图为空时显示文本视图，您可以这样做：

ArrayList<SomeDataModel> arrayList = new ArrayList<>();

RecycleAdapter recycleAdapter =  new RecycleAdapter(getContext(),project_Ideas);

recyclerView..setAdapter(recycleAdapter);

if(arrayList.isEmpty())
{
    emptyTextView.setVisibility(View.VISIBLE);
    recyclerView.setVisibility(View.GONE);
}

我假设你有 TextView

和像这样的XML

 android:visibility="gone"
于 2020-11-13T12:53:02.327 回答
0

这是如何在使用 LiveData 过滤和更新 RecyclerView时显示空视图

    ViewModel.getInstance().getCustomers?.observe(viewLifecycleOwner, {customerList ->
           //assign your adapter with your list then
        listAdapter?.notifyDataSetChanged()
        isListItemEmpty(customerList?.isEmpty())
}

创建一个接口在适配器和片段之间进行通信，并将其注册到适配器内部

 interface EmptyListener {
            fun isListEmpty(isEmpty: Boolean)
        }

然后在 publishResults 中调用它：

        dataList?.isEmpty()?.let { mListener?.isListEmpty(it) }

最后在 Fragment 内部实现你的接口：

 override fun isListEmpty(isEmpty: Boolean) {
        if (isEmpty) {
            your_list?.visibility = View.GONE
            empty_view?.visibility = View.VISIBLE
        } else {
            empty_view?.visibility = View.GONE
            your_list?.visibility = View.VISIBLE
        }
    }
于 2021-09-03T17:34:30.590 回答