SupportRecyclerView.java

/**
 * Copyright 2016 JustWayward Team
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.justwayward.reader.view;

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.View;

import com.justwayward.reader.utils.LogUtils;


/**
 * 支持emptyView
 *
 * @author yuyh.
 * @date 16/6/10.
 */
public class SupportRecyclerView extends RecyclerView {
    private View emptyView;

    private AdapterDataObserver emptyObserver = new AdapterDataObserver() {
        @Override
        public void onChanged() {
            LogUtils.i("adapter changed");
            Adapter adapter = getAdapter();
            if (adapter != null && emptyView != null) {
                if (adapter.getItemCount() == 0) {
                    LogUtils.i("adapter visible");
                    emptyView.setVisibility(View.VISIBLE);
                    SupportRecyclerView.this.setVisibility(View.GONE);
                } else {
                    LogUtils.i("adapter gone");
                    emptyView.setVisibility(View.GONE);
                    SupportRecyclerView.this.setVisibility(View.VISIBLE);
                }
            }

        }
    };

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

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

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

    public void setAdapter(Adapter adapter) {
        Adapter oldAdapter = getAdapter();
        if (oldAdapter != null && emptyObserver != null) {
            oldAdapter.unregisterAdapterDataObserver(emptyObserver);
        }
        super.setAdapter(adapter);

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

    /**
     * set view when no content item
     *
     * @param emptyView visiable view when items is empty
     */
    public void setEmptyView(View emptyView) {
        this.emptyView = emptyView;
    }
}