RecyclerView设置空视图

RecyclerView貌似不能直接设置空视图，所以可以自定义一个RecyclerView继承自RecyclerView并设置一个数据监听者监视数据状态。

MyCyclerView.java

package com.onepilltest.others;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;

public class MyRecyclerView extends RecyclerView {

    private View emptyView;
    private static final String TAG = "EmptyRecyclerView";

    //数据监听者
    final private AdapterDataObserver adapterDataObserver = new AdapterDataObserver() {
        @Override
        public void onChanged() {
            checkIfEmpty();
        }

        @Override
        public void onItemRangeInserted(int positionStart, int itemCount) {
            Log.i(TAG, "onItemRangeInserted" + itemCount);
            checkIfEmpty();
        }

        @Override
        public void onItemRangeRemoved(int positionStart, int itemCount) {
            checkIfEmpty();
        }
    };

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

    @Override
    public void setAdapter(@Nullable Adapter adapter) {
        final Adapter oldAdapter = getAdapter();
        if (oldAdapter != null) {
            oldAdapter.unregisterAdapterDataObserver(adapterDataObserver);
        }
        super.setAdapter(adapter);
        if (adapter != null) {
            adapter.registerAdapterDataObserver(adapterDataObserver);
        }

        checkIfEmpty();
    }

    //设置没有内容时，提示用户的空布局
    public void setEmptyView(View emptyView) {
        this.emptyView = emptyView;
        checkIfEmpty();
    }

    public MyRecyclerView(@NonNull Context context) {
        super(context);
    }

    public MyRecyclerView(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public MyRecyclerView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }
}

使用时和正常的RecyclerView一样，设置空视图时只需要调用setEmptyView即可。

recyclerView = findViewById(R.id.focus_list_list);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);
        mEmptyView = findViewById(R.id.empty_iv);