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2024-04-01 09:00:06

如何用RecyclerView显示一个空视图?

我习惯于在布局文件中放置一个特殊的视图，如ListActivity文档中所述，在没有数据时显示。这个视图的id为“android:id/empty”。

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

我想知道这如何能与新的RecyclerView?

当前回答

在定义了RecyclerView的相同布局上，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RecyclerView的数据集是否为空。 如果数据集为空，那么RecyclerView也是空的。在这种情况下，消息将显示在屏幕上。 如果不是，改变它的可见性:

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);
}
2015-02-05 19:16:13

其他回答

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

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

其中，recycler_view & empty_data_parent是布局在你的活动，约束这些视图，你想要的，使其可见性消失。然后用图像和文本创建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" />

下面是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>

和这个EmptyDataObserver类来做这项工作。

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)
    }

}
2021-05-03 14:57:36

在定义了RecyclerView的相同布局上，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RecyclerView的数据集是否为空。 如果数据集为空，那么RecyclerView也是空的。在这种情况下，消息将显示在屏幕上。 如果不是，改变它的可见性:

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);
}
2015-02-05 19:16:13

我添加了RecyclerView和替代ImageView到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>

然后在适配器中:

@Override
public int getItemCount() {
    if (mOrders.size() == 0) {
        mRecyclerView.setVisibility(View.INVISIBLE);
    } else {
        mRecyclerView.setVisibility(View.VISIBLE);
    }
    return mOrders.size();
}
2016-01-29 14:41:59

下面是一种解决方案，它仅使用一个自定义适配器，为空情况使用不同的视图类型。

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);
        }
    }

}
2016-03-07 15:05:43

这里是我的类显示空视图，重试视图(当加载api失败时)和加载进度的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();
    }
}

activity_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>

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

2017-07-14 10:29:28

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