Andrroid RecyclerView的基本使用

什么是RecyclerView

关于RecyclerView，是一个主要用于展示和回收View的有一个控件，在官用了一句话来概括

RecyclerView 是一种通过提供有限的数据项窗口有效显示大数据集的视图。

基提供几个基本的功能，

• 控制其显示的方式 ———>LayoutManager—(必需)
• 控制Item间的间隔 ———>ItemDecoration—-(非必需)
• 控制Item增删的动画——->ItemAnimator——(非必需)

以上就可以完成ListView大部的功能了，但是确缺少了一个很常用的功能，就是Item的点需事件。当然，这个并不是什么问题，上文也说了，RecyclerView是一个用于控制view展示的回收的，其它的都由用户去定制。给了用户当的自由度。下面来看一些基本的使方式。

基本使用

由于RecyclerView并不是在android的基本库中，所以如果开发者需要使用RecyclerView里，需要gradle引用对应的扩展包，

 compile 'com.android.support:recyclerview-v7:25.0.1'

这后实大家需要做的和使用ListView差别也不大，只需要调置LayoutManager和Adapter就可以完成最基础的显示了。Adapter及Adapter需要的ViewHolder均继承自RecyvlerView的内部类。

RecyclerView的Adapter

public class DemoAdapter extends RecyclerView.Adapter<DemoViewHolder> {
    private List data;

    public DemoAdapter(List data) {
        this.data = data;
    }

    @Override
    public DemoViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        DemoViewHolder holder = new DemoViewHolder(LayoutInflater.from(
                parent.getContext()).inflate(R.layout.demo_recycler_view_item, parent,
                false));
        return holder;
    }

    @Override
    public void onBindViewHolder(DemoViewHolder holder, int position) {
        holder.getView().setText(data.get(position));
    }

    @Override
    public int getItemCount() {
        return data.size();
    }
}

RecyclerView的ViewHolder

public class DemoViewHolder extends RecyclerView.ViewHolder {

    private TextView view;

    public DemoViewHolder(View itemView) {
        super(itemView);
        view = (TextView) itemView.findViewById(R.id.item_view);
    }

    public TextView getView() {
        return view;
    }
}

项目主Activity

public class RecyclerViewDemoActivity extends AppCompatActivity {

    private RecyclerView recyclerView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_recycler_view_demo);
        recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        String[] datas = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "0"};
        List strings = Arrays.asList(datas);
        DemoAdapter adapter = new DemoAdapter(strings);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(adapter);

    }

}

activity layout文件布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_recycler_view_demo"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.yjeeq.study.recyclerview.RecyclerViewDemoActivity">

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

    android.support.v7.widget.RecyclerView>
RelativeLayout>

item layout文件布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="40dp"
    android:orientation="vertical">

    <TextView
        android:id="@+id/item_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/holo_blue_dark"
        android:gravity="center" />
LinearLayout>

以下是运行效果

设置单击事件

上面已经完成基本的展示，这里就介绍一下怎么为Recycler加上点击事件。其实思路很简单，就是在RecyclerView上的addOnItemTouchListener上做文章。这里给出具体实现。相信大家一看就懂。

* OnItemTouchListener的实现*

public class RecyclerItemClickListener implements RecyclerView.OnItemTouchListener {
    private View childView;
    private RecyclerView touchView;

    public RecyclerItemClickListener(Context context, final OnItemClickListener mListener) {
        mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
            @Override
            public boolean onSingleTapUp(MotionEvent ev) {
                if (childView != null && mListener != null) {
                    mListener.onItemClick(childView, touchView.getChildPosition(childView));
                }
                return true;
            }

            @Override
            public void onLongPress(MotionEvent ev) {
                if (childView != null && mListener != null) {
                    mListener.onLongClick(childView, touchView.getChildAdapterPosition(childView));
                }
            }
        });
    }

    GestureDetector mGestureDetector;

    public interface OnItemClickListener {
        public void onItemClick(View view, int position);

        public void onLongClick(View view, int posotion);
    }

    @Override
    public boolean onInterceptTouchEvent(RecyclerView recyclerView, MotionEvent motionEvent) {
        mGestureDetector.onTouchEvent(motionEvent);
        childView = recyclerView.findChildViewUnder(motionEvent.getX(), motionEvent.getY());
        touchView = recyclerView;
        return false;
    }

    @Override
    public void onTouchEvent(RecyclerView recyclerView, MotionEvent motionEvent) {

    }

    @Override
    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

    }
}  

使用方式
首先在主类继承 RecyclerItemClickListener.OnItemClickListener，之后在主类中添加如下方法。

     private void setOnItemClick() {
        recyclerView.addOnItemTouchListener(new RecyclerItemClickListener(this, this));

    }

     public void onItemClick(View view, int position) {
        Log.d("XXXXXX", "onItemClick : postion " + position);
    }

    @Override
    public void onLongClick(View view, int posotion) {
        Log.d("XXXXXX", "onLongClick position : " + posotion);
    }

基本使用参考 : http://blog.csdn.net/lmj623565791/article/details/45059587
点击是件参考 : http://blog.csdn.net/hlglinglong/article/details/44981889