RecycleView

RecyclerView实现效果图如下：

该控件用于在有限的窗口中展示大量数据集，其实这样功能的控件我们并不陌生，例如：ListView、GridView。 那么有了ListView、GridView为什么还需要RecyclerView这样的控件呢？整体上看RecyclerView架构，提供了一种插拔式的体验，高度的解耦，异常的灵活，通过设置它提供的不同LayoutManager，ItemDecoration , ItemAnimator实现令人瞠目的效果。

你想要控制其显示的方式，请通过布局管理器LayoutManager
你想要控制Item间的间隔（可绘制），请通过ItemDecoration
你想要控制Item增删的动画，请通过ItemAnimator
你想要控制点击、长按事件，请自己写（擦，这点尼玛。）

基本使用

mRecyclerView = findView(R.id.id_recyclerview);
//设置布局管理器
mRecyclerView.setLayoutManager(layout);
//设置adapter
mRecyclerView.setAdapter(adapter)
//设置Item增加、移除动画
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
//添加分割线
mRecyclerView.addItemDecoration(new DividerItemDecoration(
                getActivity(), DividerItemDecoration.HORIZONTAL_LIST));

Activity简单写法

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        loadData();
        onRecyclerListener();
    }

    private void loadData() {
        for(int i=0;i<21;i++){
            list.add("嘿嘿嘿"+i);
        }
        adapter.notifyDataSetChanged();
    }

   private void initView() {
        //设置RecyclerView的排列方式
        //LinearLayoutManager manager = new LinearLayoutManager(this);
        //manager.setOrientation(LinearLayoutManager.VERTICAL);

        //GridLayoutManager manager = new GridLayoutManager(this,3);
        //manager.setOrientation(GridLayoutManager.VERTICAL);

        //StaggeredGridLayoutManager manager = new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL);
       // recyclerView.setLayoutManager(manager);
        //recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL));
        //自定义ListView分割线的样式
        //recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.HORIZONTAL_LIST));
        //recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
        //自定义GridView分割线的样式
        //recyclerView.addItemDecoration(new DividerGridItemDecoration(this));

        addItem = (TextView) findViewById(R.id.addItem);
        deleteItem = (TextView) findViewById(R.id.deleteItem);
        changeList = (TextView) findViewById(R.id.changeListView);
        changeGrid = (TextView) findViewById(R.id.changeGridView);
        changeStaggered = (TextView) findViewById(R.id.changeStaggered);
        addItem.setOnClickListener(this);
        deleteItem.setOnClickListener(this);
        changeList.setOnClickListener(this);
        changeGrid.setOnClickListener(this);
        changeStaggered.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.addItem:
                adapter.addItem("ZZ");
                break;
            case R.id.deleteItem:
                adapter.deleteItem(0);
                break;
            case R.id.changeListView:
                //设置Listview显示方式
                recyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));
                break;
            case R.id.changeGridView:
                //设置GridView显示方式
                recyclerView.setLayoutManager(new GridLayoutManager(this,3,GridLayoutManager.VERTICAL,false));
                break;
            case R.id.changeStaggered:
                //设置流式显示方式
                recyclerView.setLayoutManager(new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL));
                break;
        }
    }

Adapter中简单写法

    public class RecyclerAdapter extends RecyclerView.Adapter {
    private ArrayList<String>list;
    private Context context;
    private OnRecyclerItemListener listener;
    public RecyclerAdapter(Context context,ArrayList<String> list) {
        this.list = list;
        this.context = context;
    }
    public void setOnItemClickListener(OnRecyclerItemListener listener){
        this.listener = listener;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).inflate(R.layout.recycler_item,null);
        ViewHolder holder = new ViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
        String data = list.get(position);
        final ViewHolder vh = (ViewHolder) holder;
        vh.title.setText(data);
        vh.title.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                listener.onItemClick(vh.title,position,position);
            }
        });
    }

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

    class ViewHolder extends RecyclerView.ViewHolder {

        private TextView title;

        public ViewHolder(View itemView) {
            super(itemView);
            title = (TextView) itemView.findViewById(R.id.titel);
        }
    }
    //设置接口，用来监听点击事件
    public interface OnRecyclerItemListener{
        public void onItemClick(View view,int postion,int id);
    }
    //点击添加
    public void addItem(String data){
        if (list!=null){
            list.add(data);
            notifyDataSetChanged();
        }
    }
    //点击删除
    public void deleteItem(String data){
        if (list!=null){
            list.remove(data);
            notifyDataSetChanged();
        }
    }
}

Activity的xml文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <android.support.v7.widget.RecyclerView
        android:id="@+id/id_recyclerview"
         android:divider="#ffff0000"
           android:dividerHeight="10dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

Adapter的item视图

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:background="#44ff0000"
    android:layout_height="wrap_content" >

    <android.support.v7.widget.CardView
        android:layout_width="140dp"
        android:layout_height="wrap_content"
        app:cardBackgroundColor="#ff6699"
        android:layout_marginLeft="10dp"
        android:layout_marginTop="10dp"
        app:cardCornerRadius="15dp"
        app:cardElevation="15dp"
        app:cardPreventCornerOverlap="true">
        <TextView
            android:id="@+id/titel"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center"
            android:layout_gravity="center"
            android:textColor="#ffffff"
            android:textSize="20sp"/>

    </android.support.v7.widget.CardView>
</FrameLayout>

RecyclerView并没有支持divider这样的属性。那么怎么办，你可以给Item的布局去设置margin，当然了这种方式不够优雅，我们文章开始说了， 我们可以自由的去定制它，当然我们的分割线也是可以定制的。

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) {
        Log.v("recyclerview - itemdecoration", "onDraw()");

        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);
            android.support.v7.widget.RecyclerView v = new android.support.v7.widget.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);
        }
    }
}

自定义分割线使用如下

mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST));

该分割线是系统默认的，你可以在theme.xml中找到该属性的使用情况。那么，使用系统的listDivider有什么好处呢？就是方便我们去随意的改变，该属性我们可以直接声明在：

<style name="AppTheme" parent="AppBaseTheme">
  <item name="android:listDivider">@drawable/divider_bg</item>  
</style>
<?xml version="1.0" encoding="utf-8"?>

<gradient
    android:centerColor="#ff00ff00"
    android:endColor="#ff0000ff"
    android:startColor="#ffff0000"
    android:type="linear" />
<size android:height="4dp"/>

然后自己写个drawable即可，下面我们换一种分隔符：