Android学习RecyclerView小结

RecyclerView是google推出用来代替ListView和GridView的新控件。我花了一天半的时间对该控件的基本用法进行学习以及掌握，为以后的工作做铺垫。首先RecyclerView是在android的support-v7包中，如果用Android studio直接在gradle文件之配置以下代码：compile 'com.android.support:recyclerview-v7:22.2.0' 如果用eclipse的话可以将对应的jar包拷贝到libs目录下。准备工作做完以后就可以上代码了，要填充布局就少不了adapter,RecyclerView内部维护着一个Adapter我们可以直接extends该类。要显示不同的样式我们还要为其设置不同的LayoutManager，通过它们不同构造方法设置orientation的不同值实现水平和垂直不同方向上的滑动效果

LinearLayoutManager（线性的布局）
GridLayoutManager（网格的布局）
StaggeredGridLayoutManager（流式布局）

为了条目的复用其内部也提供了相应的ViewHolder减少了以前listView等自己写viewholder的代码量，只需要定义一个类去extends
RecyclerView.ViewHolder就可以了，然后再在构造方法中初始化Item中相关控件。

分割线的设置如下:

//设置RecyclerView的分割线mItemDecoration = new DividerItemDecoration(mContext, DividerItemDecoration.VERTICAL_LIST);mRecyclerView.addItemDecoration(mItemDecoration);

我们可以在styles文件中配置一下代码来改变其分割线的样式：

<item name="android:listDivider">@drawable/divider_2</item>

divider_2.xml是drawable目录一下一个具有渐变效果的shape资源，如下：

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" >    <!--自定义分割线样式-->    <size android:height="4dp"/>    <gradient  android:centerColor="#00ff00" android:endColor="#0000ff" android:startColor="#ffff0000"></gradient></shape>

DividerItemDecoration这个类是一个第三方提供的类，代码如下：

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) {        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);            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);        }    }}

RecyclerView没有提供相应的条目点击事件，所以只能我们自定义接口进行事件的监听操作。
具体代码如下：

/** * Created by rongtao on 2016/3/21. */public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {    private LayoutInflater mLayoutInflater;    private Context mContext;    private List<String> datas;    //条目点击事件的回调监听    private OnItemClickListener mItemClickListener;    public void setItemClickListener(OnItemClickListener itemClickListener) {        this.mItemClickListener=itemClickListener;    }    public interface OnItemClickListener {//自定义接口，监听相应的点击事件        void onClickItem(View view, int position);        void onLongClickItem(View view, int position);    }    public MyAdapter(Context context, List<String> data) {        super();        this.mContext = context;        this.datas = data;        mLayoutInflater = LayoutInflater.from(mContext);    }    @Override    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        View view = mLayoutInflater.inflate(R.layout.list_item, null);        MyViewHolder myViewHolder = new MyViewHolder(view);        return myViewHolder;    }    @Override    public void onBindViewHolder(final MyViewHolder holder, final int position) {        holder.tv_item.setText(datas.get(position));        if (null != mItemClickListener) { //处理相应的点击操作           holder.tv_item.setOnClickListener(new View.OnClickListener() {               @Override               public void onClick(View v) {                   int pos=holder.getLayoutPosition();//获取当前布局的位置，避免点击条目错误的bug                   mItemClickListener.onClickItem(holder.tv_item,pos);               }           });            holder.tv_item.setOnLongClickListener(new View.OnLongClickListener() {                @Override                public boolean onLongClick(View v) {                    int pos=holder.getLayoutPosition();                    mItemClickListener.onLongClickItem(holder.tv_item, pos);                    return false;                }            });        }    }    @Override    public int getItemCount() {        return datas.size();    }}class MyViewHolder extends RecyclerView.ViewHolder {    TextView tv_item;    public MyViewHolder(View itemView) {        super(itemView);        tv_item = (TextView) itemView.findViewById(R.id.tv_item);    }}

RecyclerView没有提供相应的条目点击事件，所以只能我们自定义接口进行事件的监听操作。
具体代码如下：

/** * Created by rongtao on 2016/3/21. */public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {    private LayoutInflater mLayoutInflater;    private Context mContext;    private List<String> datas;    //条目点击事件的回调监听    private OnItemClickListener mItemClickListener;    public void setItemClickListener(OnItemClickListener itemClickListener) {        this.mItemClickListener=itemClickListener;    }    public interface OnItemClickListener {//自定义接口，监听相应的点击事件        void onClickItem(View view, int position);        void onLongClickItem(View view, int position);    }    public MyAdapter(Context context, List<String> data) {        super();        this.mContext = context;        this.datas = data;        mLayoutInflater = LayoutInflater.from(mContext);    }    @Override    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        View view = mLayoutInflater.inflate(R.layout.list_item, null);        MyViewHolder myViewHolder = new MyViewHolder(view);        return myViewHolder;    }    @Override    public void onBindViewHolder(final MyViewHolder holder, final int position) {        holder.tv_item.setText(datas.get(position));        if (null != mItemClickListener) { //处理相应的点击操作           holder.tv_item.setOnClickListener(new View.OnClickListener() {               @Override               public void onClick(View v) {                   int pos=holder.getLayoutPosition();//获取当前布局的位置，避免点击条目错误的bug                   mItemClickListener.onClickItem(holder.tv_item,pos);               }           });            holder.tv_item.setOnLongClickListener(new View.OnLongClickListener() {                @Override                public boolean onLongClick(View v) {                    int pos=holder.getLayoutPosition();                    mItemClickListener.onLongClickItem(holder.tv_item, pos);                    return false;                }            });        }    }    @Override    public int getItemCount() {        return datas.size();    }}class MyViewHolder extends RecyclerView.ViewHolder {    TextView tv_item;    public MyViewHolder(View itemView) {        super(itemView);        tv_item = (TextView) itemView.findViewById(R.id.tv_item);    }}

最后我们看一下流式布局，规则的流式布局和Grid布局基本展示区别不大，所以我们对Adapter进行相应的修改以实现不规则的流式布局的感觉。
代码如下：

/** * Created by rongtao on 2016/3/21. */public class StaggeredAdapter extends RecyclerView.Adapter<StaggeredAdapter.MyViewHolder> {    private LayoutInflater mLayoutInflater;    private Context mContext;    private List<String> datas;    private List<Integer> mHeights;    public StaggeredAdapter(Context context, List<String> data) {        super();        this.mContext = context;        this.datas = data;        mLayoutInflater = LayoutInflater.from(mContext);        mHeights=new ArrayList<Integer>();        for (int i = 0; i <datas.size(); i++) {//随机产生100~400之间的整数，实现不规则的感觉            mHeights.add((int) (100 + Math.random() * 300));        }    }    //条目点击事件的回调监听    private OnItemClickListener mItemClickListener;    public void setItemClickListener(OnItemClickListener itemClickListener) {        this.mItemClickListener=itemClickListener;    }    public interface OnItemClickListener {        void onClickItem(View view, int position);        void onLongClickItem(View view, int position);    }    @Override    public StaggeredAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        View view = mLayoutInflater.inflate(R.layout.list_item, null);        MyViewHolder myViewHolder = new MyViewHolder(view);        return myViewHolder;    }    @Override    public void onBindViewHolder(final StaggeredAdapter.MyViewHolder holder, int position) {        ViewGroup.LayoutParams lp=holder.tv_item.getLayoutParams();        lp.height=mHeights.get(position);        holder.tv_item.setLayoutParams(lp);        holder.tv_item.setText(datas.get(position));        updateAdapter(holder);    }    private void updateAdapter(final MyViewHolder holder) {        if (null != mItemClickListener) {            holder.tv_item.setOnClickListener(new View.OnClickListener() {                @Override                public void onClick(View v) {                    int pos=holder.getLayoutPosition();//获取当前布局的位置，避免点击条目错误的bug                    mItemClickListener.onClickItem(holder.tv_item,pos);                }            });            holder.tv_item.setOnLongClickListener(new View.OnLongClickListener() {                @Override                public boolean onLongClick(View v) {                    int pos=holder.getLayoutPosition();                    mItemClickListener.onLongClickItem(holder.tv_item, pos);                    return false;                }            });        }    }    @Override    public int getItemCount() {        return datas.size();    }    class MyViewHolder extends RecyclerView.ViewHolder {        TextView tv_item;        public MyViewHolder(View itemView) {            super(itemView);            tv_item = (TextView) itemView.findViewById(R.id.tv_item);        }    }}

效果如下图：

具体代码如下链接：http://pan.baidu.com/s/1skyIYZV 密码：bpgp

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