RecyclerView的用法

回顾ListView

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概述

一句话:在有限的空间中显示大量的列表集合的控件

ListView的使用步骤(question)

• 1.数据集
• 2.适配器Adapter

备注：其实ListView是一个MVC的模式，

M--Model 数据集V--View ListViewC--Controller 适配器

RecyclerView的介绍

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概述

• 官方的介绍，该控件用于在有限的窗口中展示大量数据集。正如我们刚才介绍ListView和之前所学过的ListView

• Google在2014年I/O大会上提出新的用于取代ListView的组件,相比ListView而言，它更加强大，而且非常灵活

原理以及结构图

• 官方结构图

• RecyclerView描述

  • 与其它的View不一样的地方是RecyclerView不负责子view的展现和布局工作。即子view的位置、大小等都不由RecyclerView自己负责。它所关注的是子view的回收与复用，专注于性能的提升。而其它的工作如布局、子view的布局、子view的装饰、子view的动画都交给了其内部类来负责，下表展示了几个关键的内部类和它们的用途。

• RecyclerView的相关类

RecyclerView的初体验

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显示类似于ListView的列表

• 1.首先要用这个控件，你需要在gradle文件中添加包的引用

compile 'com.android.support:recyclerview-v7:21.0.3'

• 2.在布局文件中用使用它

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

• 3.设置适配器

  • (1) 准备适配器继承RecyclerView.Adapter
  • (2)RecyclerView.Adapter中默认必须有ViewHolder,需要在Adapter中写一个内部类继承RecyclerView.ViewHolder

• 示例代码如下：

 * step: * 1. 继承RecyclerView.Adapter<VH extends ViewHolder> * 2. 在这个Adapter中写一个类继承RecyclerView.ViewHolder,并且传入Adapter的泛型 * 3. 实现 三个抽象方法 * getItemCount * onCreateViewHolder * onBindViewHolder * 4. 重写构造方法,参数传入 上下文Context 数据集 * ************************************************************* */public class LikeListAdapter extends RecyclerView.Adapter<LikeListAdapter.MyViewHolder> {    private List<String> mDatas = new ArrayList<>();    private Context mContext;    private LayoutInflater mInflater;    public LikeListAdapter(Context context, List<String> datas) {        this.mInflater = LayoutInflater.from(context);        mDatas = datas;        this.mContext = context;    }    //返回RecyclerView总共有多少条    @Override    public int getItemCount() {        return mDatas == null ? 0 : mDatas.size();    }    //初始化布局,创建ViewHolder    @Override    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        //1. 初始化item的布局        View view = mInflater.inflate(R.layout.item_likelist, parent, false);        //2. 创建出来ViewHolder对象        MyViewHolder myViewHolder = new MyViewHolder(view);        return myViewHolder;    }    //绑定ViewHolder中的控件的数据    @Override    public void onBindViewHolder(final MyViewHolder holder, final int position) {        String str = mDatas.get(position);        holder.itemView.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {//                Toast.makeText(mContext, "pos:" + position, Toast.LENGTH_SHORT).show();                if (mListener != null) {                    mListener.onItemClick(position, holder.itemView);                }            }        });        //瀑布流展示//        Random random = new Random();//        int height = random.nextInt(100) + 100;//        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, height);//        ViewGroup.LayoutParams layoutParams = holder.tv_test.getLayoutParams();//        layoutParams.height = height;//        holder.tv_test.setLayoutParams(layoutParams);        holder.tv_test.setText(str);    }    public class MyViewHolder extends RecyclerView.ViewHolder {        private TextView tv_test;        public MyViewHolder(View itemView) {            super(itemView);            tv_test = (TextView) itemView.findViewById(R.id.tv_test);        }    }    //增加一条数据    public void insertData(int pos, String data) {        mDatas.add(pos, data);        notifyItemInserted(pos);    }    //删除一条数据    public void removeData(int pos) {        mDatas.remove(pos);        notifyItemRemoved(pos);    }    public interface OnItemClickListener {        void onItemClick(int pos, View view);    }    private OnItemClickListener mListener;    public void setOnItemClickListener(OnItemClickListener listener) {        this.mListener = listener;    }}

• (4)设置布局管理器LayoutManager

  • LinearLayoutManager线性布局
  • GridLayoutManager网格布局
  • StaggeredGridLayoutManager瀑布流布局

public class LikeListActivity extends AppCompatActivity {    private List<String> mDatas = new ArrayList<>();    private RecyclerView mRecyclerView;    private Button btn_add;    private Button btn_remove;    private LikeListAdapter mAdapter;    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_likelist);        mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);        btn_add = (Button) findViewById(R.id.btn_add);        btn_remove = (Button) findViewById(R.id.btn_remove);        //1.准备数据集        for (int i = 0; i < 50; i++) {            mDatas.add("data:" + i);        }        //2.初始化Adapter        mAdapter = new LikeListAdapter(this, mDatas);        mRecyclerView.setAdapter(mAdapter);        //3.创建出来LayoutManager        //3.1 线性布局: 第二个参数是 列表展现的方向,有竖直的LinearLayoutManager.VERTICAL 和 水平的LinearLayoutManager.HORIZONTAL        // 第三个参数: 是否 从最后展示        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);        //3.2 网格布局:  参数2是 表示这个网格布局的列数 或者行数        GridLayoutManager gridLayoutManager = new GridLayoutManager(this, 3, GridLayoutManager.VERTICAL, false);        //3.3 瀑布流布局        StaggeredGridLayoutManager staggeredGridLayoutManager = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);        mRecyclerView.setLayoutManager(linearLayoutManager);        //给RecyclerView增加一些动画效果//        mRecyclerView.setItemAnimator(new DefaultItemAnimator());        //1. build.gradle中引入 : compile 'jp.wasabeef:recyclerview-animators:2.2.5'        //2. 添加动画效果 :  setItemAnimator(动画效果的类例如: SlideInLeftAnimator, SlideInRightAnimator);        mRecyclerView.setItemAnimator(new LandingAnimator());        //3. 改变动画的时长:  有四个:        // recyclerView.getItemAnimator().setAddDuration(1000);        //recyclerView.getItemAnimator().setRemoveDuration(1000);        //recyclerView.getItemAnimator().setMoveDuration(1000);        //recyclerView.getItemAnimator().setChangeDuration(1000);        mRecyclerView.getItemAnimator().setAddDuration(3000);        //增加一条数据        btn_add.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                mAdapter.insertData(1, "新增加的数据");            }        });        //删除一条数据        btn_remove.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                mAdapter.removeData(1);            }        });//        mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST));        mAdapter.setOnItemClickListener(new LikeListAdapter.OnItemClickListener() {            @Override            public void onItemClick(int pos, View view) {                Toast.makeText(LikeListActivity.this, "pos::" + pos, Toast.LENGTH_SHORT).show();            }        });    }}

设置动画效果

三方地址

https://github.com/gabrielemariotti/RecyclerViewItemAnimators

具体操作如下：

//给RecyclerView增加一些动画效果//        mRecyclerView.setItemAnimator(new DefaultItemAnimator());        //1. build.gradle中引入 : compile 'jp.wasabeef:recyclerview-animators:2.2.5'        //2. 添加动画效果 :  setItemAnimator(动画效果的类例如: SlideInLeftAnimator, SlideInRightAnimator);        mRecyclerView.setItemAnimator(new LandingAnimator());        //3. 改变动画的时长:  有四个:        // recyclerView.getItemAnimator().setAddDuration(1000);        //recyclerView.getItemAnimator().setRemoveDuration(1000);        //recyclerView.getItemAnimator().setMoveDuration(1000);        //recyclerView.getItemAnimator().setChangeDuration(1000);

设置分割线

具体操作如下：

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);            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);        }    }}

RecyclerView的高级用法(多布局的实现)

MultiAdapter写法如下

 * step: * 1. 有几种类型,就写几个ViewHolder, Adapter中的泛型传入RecyclerView.ViewHolder * 2. 有几种类型,就写几种int 类型常量, 一般从0开始 * 3. 覆写方法getItemViewType(int pos) , 返回当前位置到底是那种类型 * 4. 通过onCreateViewHolder(ViewGroup parent, int viewType)  中的 第二个参数 viewType 去创建不同的ViewHolder对象 * ************************************************************* */public class MultiAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {    public Context mContext;    public LayoutInflater mInflater;    public List<HouseBean.DataBean> mDatas;    //有几种类型 就写一个常量去标记    private static final int TYPE_SPECIAL = 0;    private static final int TYPE_NORMAL = 1;    private static final int TYPE_BIG = 2;    public MultiAdapter(Context context, List<HouseBean.DataBean> datas) {        this.mContext = context;        this.mInflater = LayoutInflater.from(context);        this.mDatas = datas;    }    @Override    public int getItemCount() {        return mDatas == null ? 0 : mDatas.size();    }    //返回当前位置的类型    @Override    public int getItemViewType(int position) {        String type = mDatas.get(position).type;        if ("100".equals(type)) {            return TYPE_SPECIAL;        } else if ("0".equals(type)) {            return TYPE_NORMAL;        } else {            return TYPE_BIG;        }    }    @Override    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        switch (viewType) {            case TYPE_SPECIAL://                View view = mInflater.inflate(R.layout.item_multi_special, parent, false);//                return new SpecialHolder(view);                return new SpecialHolder(mInflater.inflate(R.layout.item_multi_special, parent, false));            case TYPE_NORMAL:                return new NormalHolder(mInflater.inflate(R.layout.item_multi_normal, parent, false));            case TYPE_BIG:                return new BigImgHolder(mInflater.inflate(R.layout.item_multi_big, parent, false));        }        return null;    }    @Override    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {        int itemViewType = getItemViewType(position);        HouseBean.DataBean bean = mDatas.get(position);        switch (itemViewType) {            case TYPE_SPECIAL:                SpecialHolder specialHolder = (SpecialHolder) holder;                specialHolder.tv_title.setText(bean.title);                specialHolder.tv_desc.setText(bean.summary);                Picasso.with(mContext)                        .load(bean.groupthumbnail)                        .placeholder(R.mipmap.ic_launcher)                        .error(R.mipmap.ic_launcher)                        .into(specialHolder.iv_special);                break;            case TYPE_NORMAL:                NormalHolder normalHolder = (NormalHolder) holder;                normalHolder.tv_title.setText(bean.title);                normalHolder.tv_desc.setText(bean.summary);                Picasso.with(mContext)                        .load(bean.groupthumbnail)                        .placeholder(R.mipmap.ic_launcher)                        .error(R.mipmap.ic_launcher)                        .into(normalHolder.iv_normal);                break;            case TYPE_BIG:                BigImgHolder bigImgHolder = (BigImgHolder) holder;                bigImgHolder.tv_title.setText(bean.title);                Picasso.with(mContext)                        .load(bean.groupthumbnail)                        .placeholder(R.mipmap.ic_launcher)                        .error(R.mipmap.ic_launcher)                        .into(bigImgHolder.iv_big);                break;        }    }    class SpecialHolder extends RecyclerView.ViewHolder {        private ImageView iv_special;        private TextView tv_title;        private TextView tv_desc;        public SpecialHolder(View itemView) {            super(itemView);            iv_special = (ImageView) itemView.findViewById(R.id.iv_show);            tv_title = (TextView) itemView.findViewById(R.id.tv_title);            tv_desc = (TextView) itemView.findViewById(R.id.tv_desc);        }    }    class NormalHolder extends RecyclerView.ViewHolder {        private ImageView iv_normal;        private TextView tv_title;        private TextView tv_desc;        public NormalHolder(View itemView) {            super(itemView);            iv_normal = (ImageView) itemView.findViewById(R.id.iv_show);            tv_title = (TextView) itemView.findViewById(R.id.tv_title);            tv_desc = (TextView) itemView.findViewById(R.id.tv_desc);        }    }    class BigImgHolder extends RecyclerView.ViewHolder {        private ImageView iv_big;        private TextView tv_title;        public BigImgHolder(View itemView) {            super(itemView);            iv_big = (ImageView) itemView.findViewById(R.id.iv_big);            tv_title = (TextView) itemView.findViewById(R.id.tv_title);        }    }}

MultiActivity写法如下：

  * step: * 1. 从网络获得到数据源 * <p> * 2. 准备适配器 * <p> * 3. 布局管理器 * ************************************************************* */public class MultiActivity extends AppCompatActivity {    private RecyclerView mRecyclerView;    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_multi);        mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);        RequestQueue requestQueue = Volley.newRequestQueue(this);        StringRequest request = new StringRequest(Request.Method.GET, UrlString.URL_SEEHOUSE, new Response.Listener<String>() {            @Override            public void onResponse(String response) {                //TODO 得到数据 解析 显示到RecyclerView                HouseBean houseBean = new Gson().fromJson(response, HouseBean.class);                mRecyclerView.setAdapter(new MultiAdapter(MultiActivity.this, houseBean.data));                mRecyclerView.setLayoutManager(new LinearLayoutManager(MultiActivity.this));            }        }, null);        requestQueue.add(request);    }}