RecyclerView的长按多选功能

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RecyclerView的长按多选功能

主要实现功能

长按进入删除模式（使用的android官方提供的actionMode）
对点击的item进行标记（对item设置背景色）
点击ActionMode上的menu进行点击实现删除选中的item

思路

其实思路很简单，用一个HashSet保存RecyclerView的所点击的item的位置，点击删除后要操作RV中的原数据，再执行RecyclerView的notifyDataSetChanged()方法更新数据便好。

运行截图

初始状态

这里写图片描述

长按后进入ActionMode

这里写图片描述

代码

adapter

public class RvAdapter extends RecyclerView.Adapter<RvHolder>  {    private List<String> items;    private LayoutInflater inflater;    private Context context;    private OnItemClickListener onItemClickListener;    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {        this.onItemClickListener = onItemClickListener;    }    public RvAdapter(Context context, List<String> items){        this.items = items;        this.context = context;        inflater = LayoutInflater.from(context);    }    @Override    public RvHolder onCreateViewHolder(ViewGroup parent, int viewType) {        View view = inflater.inflate(R.layout.item,parent,false);        RvHolder holder = new RvHolder(view);        return holder;    }    @Override    public void onBindViewHolder(RvHolder holder, final int position) {        holder.setData(items.get(position),position);        if (onItemClickListener!=null){            holder.itemView.setOnClickListener(new View.OnClickListener() {                @Override                public void onClick(View v) {                    onItemClickListener.onItemClick(v,position);                }            });            holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {                @Override                public boolean onLongClick(View v) {                    onItemClickListener.onItemLongClick(v,position);                    return false;                }            });        }    }    public void remove(String str){        items.remove(str);        notifyDataSetChanged();    }    public String getItem(int pos){        return items.get(pos);    }    @Override    public int getItemCount() {        return items.size();    }    public interface OnItemClickListener{        void onItemClick(View view, int position);        void onItemLongClick(View view,int position);    }}

ViewHolder

class RvHolder extends RecyclerView.ViewHolder  {    private TextView textView;    public RvHolder(View itemView) {        super(itemView);        textView = (TextView) itemView.findViewById(R.id.tv);    }    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)    public void setData(String item, int position){        Set<Integer> positionSet = MainActivity.instance.positionSet;        if (positionSet.contains(position)) {            itemView.setBackground(MainActivity.instance.getResources().getDrawable(R.drawable.bg_selected));        } else {            itemView.setBackground(MainActivity.instance.getResources().getDrawable(R.drawable.btn_common));        }        textView.setText(item);    }}

Activity

public class MainActivity extends AppCompatActivity implements ActionMode.Callback {    private ActionMode actionMode;    public Set<Integer> positionSet = new HashSet<>();    private RvAdapter adapter;    public static MainActivity instance;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        instance = this;        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);        setSupportActionBar(toolbar);        List<String> items = new ArrayList<>();        for (int i=1;i<=20;i++){            items.add("第"+i+"个item");        }        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.rv);        adapter = new RvAdapter(this,items);        recyclerView.setAdapter(adapter);        recyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));        recyclerView.setItemAnimator(new DefaultItemAnimator());        adapter.setOnItemClickListener(new RvAdapter.OnItemClickListener() {            @Override            public void onItemClick(View view, int position) {                if (actionMode != null) {                    // 如果当前处于多选状态，则进入多选状态的逻辑                    // 维护当前已选的position                    addOrRemove(position);                } else {                    // 如果不是多选状态，则进入点击事件的业务逻辑                    // TODO something                }            }            @Override            public void onItemLongClick(View view, int position) {                if (actionMode == null) {                    actionMode = startSupportActionMode(MainActivity.this);                }            }        });    }    private void addOrRemove(int position) {        if (positionSet.contains(position)) {            // 如果包含，则撤销选择            positionSet.remove(position);        } else {            // 如果不包含，则添加            positionSet.add(position);        }        if (positionSet.size() == 0) {            // 如果没有选中任何的item，则退出多选模式            actionMode.finish();        } else {            // 设置ActionMode标题            actionMode.setTitle(positionSet.size() + " 已选择");            // 更新列表界面，否则无法显示已选的item            adapter.notifyDataSetChanged();        }    }    @Override    public boolean onCreateActionMode(ActionMode mode, Menu menu) {        if (actionMode == null) {            actionMode = mode;            MenuInflater inflater = mode.getMenuInflater();            inflater.inflate(R.menu.menu_delete, menu);            return true;        } else {            return false;        }    }    @Override    public boolean onPrepareActionMode(ActionMode mode, Menu menu) {        return false;    }    @Override    public boolean onActionItemClicked(ActionMode mode, MenuItem item) {        switch (item.getItemId()) {            case R.id.menu_delete:                // 删除已选                Set<String> valueSet = new HashSet<>();                for (int position : positionSet) {                    valueSet.add(adapter.getItem(position));                }                for (String val : valueSet) {                    adapter.remove(val);                }                mode.finish();                return true;            default:                return false;        }    }    @Override    public void onDestroyActionMode(ActionMode mode) {        actionMode = null;        positionSet.clear();        adapter.notifyDataSetChanged();    }}

注意

因为博主是个android初学者，这个问题耗费最长时间的地方是解决RV滑动item选中位置显示错位，要在onBindViewHolder中设置每一个item的背景色，否则RV在回收的过程中会将你在点击的时候设置的背景色回收，滑动的时候会造成错乱。

代码地址：

http://download.csdn.net/detail/srtianxia/9369762

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