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  • Android程序设计-RecyclerView的使用

    【定义】

    看到这个标题,也许你会问什么是RecyclerView?其实开始的时候我也不知道- -,下面小编将带领大家领略RecyclerView的强大之处

    RecyclerView

    【描述】

    看完这个我想大家应该知道了吧,这个东西和ListView一样,只不过,这个…在设计的时候不需要考虑上述几个功能,即使要实现这几个功能,也是很简单的,仅仅需要几句话就可以搞定的

    【使用】

    使用的时候需要导入recyclerview-v7-21.0.0的jar包,然后在布局文件中添加这个控件

                                                                   <android.support.v7.widget.RecyclerView/>

    ---------------------------------------------------------------我是一个帅帅的分割线-------------------------------------------------------

    【案例】

    小编将通过一个案例实现RecyclerView的使用,下面请看这个案例的实现效果

    1

    【关键步骤】

    1.在布局文件中添加了对用的控件后,我们需要书写代码,既然和ListView肯定需要适配器,下面我们来看下适配器

    package org.monster.recyclerviewdemo;
    
    import android.content.Context;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.TextView;
    
    import java.util.List;
    
    /**
     * Created by monster on 2015/7/9.
     * 继承RecyclerView,实现ListView的效果
     * RecyclerView中google强烈要求使用ViewHolder
     */
    public class SimpleAdapter extends RecyclerView.Adapter<MyViewHolder>{
        private List<String> mData;
        private Context context;
        private LayoutInflater mInflater;
    
        /**
         * 声明一个接口,用于实现点击事件
         */
        public interface  OnItemClickListener{
            void OnItemClick(int position,View view);
            void OnItemLongClick(int position,View view);
        }
    
        private OnItemClickListener mOnItemClickListener;
    
        public  void setOnItemClickListener(OnItemClickListener listener){
            this.mOnItemClickListener=listener;
        }
    
        /**构造方法的实现**/
    
        public SimpleAdapter(List<String> mData,Context context){
            this.mData=mData;
            this.context=context;
            mInflater=LayoutInflater.from(context);
        }
    
        /**
         * 创建ViewHolder
         * @param parent
         * @param viewType
         * @return
         */
        @Override
        public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view=mInflater.inflate(R.layout.recycler_item,parent,false);
            MyViewHolder viewHolder=new MyViewHolder(view);
            return viewHolder;
        }
    
        /**
         * 绑定ViewHolder类,即给控件赋值
         * @param holder
         * @param position
         */
        @Override
        public void onBindViewHolder(final MyViewHolder holder, final int position) {
            holder.tv.setText(mData.get(position));
            if (mOnItemClickListener!=null){
    
                holder.itemView.setOnClickListener(new View.OnClickListener() {
    
                    @Override
                    public void onClick(View v) {
                        int LayoutPosition=holder.getLayoutPosition(); //得到布局的position
                        mOnItemClickListener.OnItemClick(LayoutPosition,holder.itemView);
    
                    }
                });
    
                //longclickListener
                holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                    @Override
                    public boolean onLongClick(View v) {
                        int LayoutPosition=holder.getLayoutPosition(); //得到布局的position
                        mOnItemClickListener.OnItemLongClick(LayoutPosition,holder.itemView);
                        return false;
                    }
                });
            }
    
        }
    
        @Override
        public int getItemCount() {
            return mData.size();
        }
    
        public void addData(int position){
            mData.add(position,"Insert One");
            notifyItemInserted(position);
        }
    
        public void deleteData(int position){
            mData.remove(position);
            notifyItemRemoved(position);
        }
    }
    
    /**
     * ViewHolder类,这个类的作用主要用于实例化控件
     */
        class MyViewHolder extends RecyclerView.ViewHolder{
            TextView tv; //声明控件
            public MyViewHolder(View itemView) {
                super(itemView);
                /**初始化控件**/
                tv= (TextView) itemView.findViewById(R.id.tv);
            }
        }
    

    ps:

    代码中我们可以看到我们继承了RecyclerView.Adapter<MyViewHolder>,实现了未实现的方法,但是一定要注意,google在这里要求必须实现ViewHolder这个类,我们通过代码知道,通过设计了ViewHolder使我们的类更加的简洁了,更重要的是我们的代码更加的实用了。

    2.我们来看下MainActivity中的代码:

    package org.monster.recyclerviewdemo;
    
    import android.content.Intent;
    import android.support.v7.app.ActionBarActivity;
    import android.os.Bundle;
    import android.support.v7.widget.DefaultItemAnimator;
    import android.support.v7.widget.GridLayoutManager;
    import android.support.v7.widget.LinearLayoutManager;
    import android.support.v7.widget.RecyclerView;
    import android.support.v7.widget.StaggeredGridLayoutManager;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.View;
    import android.widget.Switch;
    import android.widget.Toast;
    
    import java.util.ArrayList;
    import java.util.List;
    
    
    public class MainActivity extends ActionBarActivity {
        private RecyclerView recyclerView;
        private List<String> mDatas;
        private SimpleAdapter adapter;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            initDatas();
    
            initView();
    
            adapter=new SimpleAdapter(mDatas,this);
            recyclerView.setAdapter(adapter);
    
            //设置RecyclerView的布局管理
            LinearLayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
            recyclerView.setLayoutManager(layoutManager);
    
            //设置RecyclerView的item间的分割线
           // recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
    
            //设置RecyclerView的动画
            recyclerView.setItemAnimator(new DefaultItemAnimator());
    
            //设置监听事件
            adapter.setOnItemClickListener(new SimpleAdapter.OnItemClickListener() {
                @Override
                public void OnItemClick(int position, View view) {
                    Toast.makeText(MainActivity.this,"Click: "+position,Toast.LENGTH_SHORT).show();
                }
    
                @Override
                public void OnItemLongClick(int position, View view) {
                    Toast.makeText(MainActivity.this,"Long click: "+position,Toast.LENGTH_SHORT).show();
                }
            });
        }
    
        private void initView() {
            recyclerView= (RecyclerView) findViewById(R.id.RecyclerView);
    
        }
    
        /**
         * 加载数据源
         */
        private void initDatas() {
            mDatas=new ArrayList<String>();
            for(int i='A';i<'z';i++){
                mDatas.add(" "+(char)i);
            }
        }
    
    
        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.menu_main, menu);
            return true;
        }
    
        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            // Handle action bar item clicks here. The action bar will
            // automatically handle clicks on the Home/Up button, so long
            // as you specify a parent activity in AndroidManifest.xml.
            int id = item.getItemId();
    
            switch (id){
                case R.id.action_add:
                    adapter.addData(1);
                    break;
    
                case R.id.action_delete:
                    adapter.deleteData(1);
                    break;
                case R.id.action_listview:
                    recyclerView.setLayoutManager(new LinearLayoutManager(this));
                    break;
                case R.id.action_gridview:
                    recyclerView.setLayoutManager(new GridLayoutManager(this,3));
                    break;
                case R.id.action_hor_gridview:
                    recyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.HORIZONTAL));
                    break;
                case R.id.action_staggered:
                    Intent i=new Intent(this,StaggerActivity.class);
                    startActivity(i);
                    break;
    
            }
    
            return super.onOptionsItemSelected(item);
        }
    }
    

    PS:

    适配器的使用和ListView的使用一样,但是这时候当我们运行程序会发现没有分割线,整个页面成一个了,所以我们需要使用addItemDecoration添加分割线

          设置RecyclerView的item间的分割线
           recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));

    Comic Sans MS在分割线的部分我们需要引入github中的一个分割线文件:

    package org.monster.recyclerviewdemo;
    
    /*
     * Copyright (C) 2014 The Android Open Source Project
     *
     * 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
     *
     *      http://www.apache.org/licenses/LICENSE-2.0
     *
     * 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.
     */
    
    import android.content.Context;
    import android.content.res.TypedArray;
    import android.graphics.Canvas;
    import android.graphics.Rect;
    import android.graphics.drawable.Drawable;
    import android.support.v7.widget.LinearLayoutManager;
    import android.support.v7.widget.RecyclerView;
    import android.util.Log;
    import android.view.View;
    
    /**
     * This class is from the v7 samples of the Android SDK. It's not by me!
     * <p/>
     * See the license above for details.
     */
    public class DividerItemDecoration extends RecyclerView.ItemDecoration
    {
    
        private static final int[] ATTRS = new int[] { android.R.attr.listDivider };
    
        public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
    
        public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
        
        
    
        private Drawable mDivider;
    
        private int mOrientation;
    
        public DividerItemDecoration(Context context, int orientation)
        {
            final TypedArray a = context.obtainStyledAttributes(ATTRS);
            mDivider = a.getDrawable(0);
            a.recycle();
            setOrientation(orientation);
        }
    
        public void setOrientation(int orientation)
        {
            if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST)
            {
                throw new IllegalArgumentException("invalid orientation");
            }
            mOrientation = orientation;
        }
    
        @Override
        public void onDraw(Canvas c, RecyclerView parent)
        {
             if (mOrientation == VERTICAL_LIST) {
                    drawVertical(c, parent);
                } else {
                    drawHorizontal(c, parent);
                }
        }
    
        public void drawVertical(Canvas c, RecyclerView parent)
        {
            final int left = parent.getPaddingLeft();
            final int right = parent.getWidth() - parent.getPaddingRight();
    
            final int childCount = parent.getChildCount();
    
            for (int i = 0; i < childCount; i++)
            {
                final View child = parent.getChildAt(i);
                RecyclerView v = new RecyclerView(
                        parent.getContext());
                final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                        .getLayoutParams();
                final int top = child.getBottom() + params.bottomMargin;
                final int bottom = top + mDivider.getIntrinsicHeight();
                mDivider.setBounds(left, top, right, bottom);
                mDivider.draw(c);
            }
        }
    
        public void drawHorizontal(Canvas c, RecyclerView parent)
        {
            final int top = parent.getPaddingTop();
            final int bottom = parent.getHeight() - parent.getPaddingBottom();
    
            final int childCount = parent.getChildCount();
            for (int i = 0; i < childCount; i++)
            {
                final View child = parent.getChildAt(i);
                final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                        .getLayoutParams();
                final int left = child.getRight() + params.rightMargin;
                final int right = left + mDivider.getIntrinsicHeight();
                mDivider.setBounds(left, top, right, bottom);
                mDivider.draw(c);
            }
        }
    
        @Override
        public void getItemOffsets(Rect outRect, int itemPosition,
                RecyclerView parent)
        {
            if (mOrientation == VERTICAL_LIST)
            {
                outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
            } else
            {
                outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
            }
        }
    }
    

    如何在RecyleView中设计布局管理?这个布局管理可以让你的页面实现ListView和GridView的自由切换

           //设置RecyclerView的布局管理
            LinearLayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
            recyclerView.setLayoutManager(layoutManager);

    如何咋RecyclerView中增加添加item和删除item的动画?

    (附录动画效果的Github链接:https://github.com/gabrielemariotti/RecyclerViewItemAnimators

          //设置RecyclerView的动画
            recyclerView.setItemAnimator(new DefaultItemAnimator());

    如何在对Recycler中的item设置监听事件?这个监听事件系统不提供,需要我们手动编写

    --->我们需要在适配器添加一个接口:

    /**
         * 声明一个接口,用于实现点击事件
         */
        public interface  OnItemClickListener{
            void OnItemClick(int position,View view);
            void OnItemLongClick(int position,View view);
        }
    
        private OnItemClickListener mOnItemClickListener;
    
        public  void setOnItemClickListener(OnItemClickListener listener){
            this.mOnItemClickListener=listener;
        }
    
        /**构造方法的实现**/
    
        public SimpleAdapter(List<String> mData,Context context){
            this.mData=mData;
            this.context=context;
            mInflater=LayoutInflater.from(context);
        }

    --->在onBindViewHolder中设置监听事件的方法

    /**
         * 绑定ViewHolder类,即给控件赋值
         * @param holder
         * @param position
         */
        @Override
        public void onBindViewHolder(final MyViewHolder holder, final int position) {
            holder.tv.setText(mData.get(position));
            if (mOnItemClickListener!=null){
    
                holder.itemView.setOnClickListener(new View.OnClickListener() {
    
                    @Override
                    public void onClick(View v) {
                        int LayoutPosition=holder.getLayoutPosition(); //得到布局的position
                        mOnItemClickListener.OnItemClick(LayoutPosition,holder.itemView);
    
                    }
                });
    
                //longclickListener
                holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                    @Override
                    public boolean onLongClick(View v) {
                        int LayoutPosition=holder.getLayoutPosition(); //得到布局的position
                        mOnItemClickListener.OnItemLongClick(LayoutPosition,holder.itemView);
                        return false;
                    }
                });
            }
    
        }

    --->>在MainActivity中调用如

    //设置监听事件
            adapter.setOnItemClickListener(new SimpleAdapter.OnItemClickListener() {
                @Override
                public void OnItemClick(int position, View view) {
                    Toast.makeText(MainActivity.this,"Click: "+position,Toast.LENGTH_SHORT).show();
                }
    
                @Override
                public void OnItemLongClick(int position, View view) {
                    Toast.makeText(MainActivity.this,"Long click: "+position,Toast.LENGTH_SHORT).show();
                }
            });

    上述即为RecyclerView的简单实用,程序中的其他样式敬请参考【源码】

    【视频】

    http://www.imooc.com/learn/424

    【源码】

    https://github.com/monsterLin/recyclerviewdemo

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  • 原文地址:https://www.cnblogs.com/boy1025/p/4635490.html
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