RecyclerView中如何实现multi-select？

Question

我正在尝试实现具有多个可选项目的 RecyclerView。

Here 是我试过的方法，但我没能成功。

这就是我想要做的：

Answer 1

我知道现在回答这个问题有点晚了。而且我不知道它是否符合OP的要求。但这可能对某人有帮助。我用一个简单的技巧实现了这个 multi-select RecyclerView。这是我的代码。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#EEE">

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

</RelativeLayout>

item_row.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginBottom="1dp"
    android:background="#FFF"
    android:clickable="true" 
    android:orientation="vertical">

   <TextView
      android:id="@+id/text_view"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:padding="10dp"
      tools:text="TextView" />

</LinearLayout>

在item_row.xml中android:clickable="true"很重要。

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private List<Model> mModelList;
    private RecyclerView mRecyclerView;
    private RecyclerView.Adapter mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        mAdapter = new RecyclerViewAdapter(getListData());
        LinearLayoutManager manager = new LinearLayoutManager(MainActivity.this);
        mRecyclerView.setHasFixedSize(true);
        mRecyclerView.setLayoutManager(manager);
        mRecyclerView.setAdapter(mAdapter);
    }

    private List<Model> getListData() {
      mModelList = new ArrayList<>();
      for (int i = 1; i <= 25; i++) {
          mModelList.add(new Model("TextView " + i));
      }
     return mModelList;
    }
}

Model.java

public class Model {

    private String text;
    private boolean isSelected = false;

    public Model(String text) {
      this.text = text;
    }

    public String getText() {
      return text;
    }

    public void setSelected(boolean selected) {
      isSelected = selected;
    }


    public boolean isSelected() {
      return isSelected;
    }
}

RecyclerViewAdapter.java

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.MyViewHolder> {

    private List<Model> mModelList;

    public RecyclerViewAdapter(List<Model> modelList) {
      mModelList = modelList;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
       View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_row, parent, false);
       return new MyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, int position) {
        final Model model = mModelList.get(position);
        holder.textView.setText(model.getText());
        holder.view.setBackgroundColor(model.isSelected() ? Color.CYAN : Color.WHITE);
        holder.textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                model.setSelected(!model.isSelected());
                holder.view.setBackgroundColor(model.isSelected() ? Color.CYAN : Color.WHITE);
            }
        });
    }

    @Override
    public int getItemCount() {
        return mModelList == null ? 0 : mModelList.size();
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {

        private View view;
        private TextView textView;

        private MyViewHolder(View itemView) {
            super(itemView);
            view = itemView;
            textView = (TextView) itemView.findViewById(R.id.text_view);
        }
    }
}

它是如何工作的？ onBindViewHolder() 方法将数据从 ArrayList 绑定到 View 对象。因此，按时将数据绑定到视图时，它会从 ArrayList 中获取当前位置为 Model model = mModelList.get(position); 的单个对象。现在我们需要检查那个特定的对象是否是 selected 的。像这样，

model.isSelected()

其中 returns true 或 false。如果该对象已经 selected，我们需要更改 row_item selected 的背景颜色。为此，这里是代码

holder.view.setBackgroundColor(model.isSelected() ? Color.CYAN : Color.WHITE);

如果 selected 将背景颜色更改为 cyan，否则 white。

对于selection我们需要使用setOnClickListener()方法。（这里我只使用 TextView。所以我在 TextView 上执行点击事件）。这里的holder.view表示整个单曲item_row。单击将布尔值切换为 true 或 false.

 holder.textView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            model.setSelected(!model.isSelected());
            holder.view.setBackgroundColor(model.isSelected() ? Color.CYAN : Color.WHITE);
        }
 });

在托管 RecyclerView 的 Activity 或 Fragment 中，您可以像这样 selected objects/items

String text = "";
 for (Model model : mModelList) {
   if (model.isSelected()) {
     text += model.getText();
   }
 }
Log.d("TAG","Output : " + text);

这是输出

编辑 1： 限制用户 select 只有一项。

 private int lastSelectedPosition = -1;  // declare this variable
 ...
 // your code
 ...

 
 @Override
public void onBindViewHolder(final MyViewHolder holder, int position) {
    final Model model = mModelList.get(position);
    holder.textView.setText(model.getText());
    holder.view.setBackgroundColor(model.isSelected() ? Color.CYAN : Color.WHITE);
    holder.textView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            // check whether you selected an item
            
            if(lastSelectedPosition > 0) {
                mModelList.get(lastSelectedPosition).setSelected(false);
            }

            model.setSelected(!model.isSelected());
            holder.view.setBackgroundColor(model.isSelected() ? Color.CYAN : Color.WHITE);

            // store last selected item position 

            lastSelectedPosition = holder.getAdapterPosition();  
        }
    });
}

希望对您有所帮助。

Answer 2

public class RecyclerColorAdapter extends RecyclerView.Adapter<RecyclerColorAdapter.ViewHolder> {


        private final Activity activity;
        private final ArrayList<ColorItem> itemArrayList;


        public RecyclerColorAdapter(Activity activity, ArrayList<ColorItem> itemArrayList) {
            super();
            this.activity = activity;
            this.itemArrayList = itemArrayList;
        }


        @Override
        public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
            View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_color_recycleview, viewGroup, false);
            return new ViewHolder(v);
        }

        @Override
        public void onBindViewHolder(final ViewHolder holder, final int i) {
            holder.setIsRecyclable(true);

            final ColorItem colorItem = itemArrayList.get(i);


            holder.button_color.setText(colorItem.getColorName());

            holder.button_color.setBackgroundColor(colorItem.isSelected() ? Color.CYAN : Color.WHITE);

            holder.button_color.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    colorItem.setSelected(!colorItem.isSelected());
                    holder.button_color.setBackgroundColor(colorItem.isSelected() ? Color.CYAN : Color.WHITE);
                    if (colorItem.isSelected()){
                        arrayListColor.add("diamond_color[]="+colorItem.getValue()+"&");
                        Log.e("arrayListColor","---------"+arrayListColor);
                    }
                    else {
                        arrayListColor.remove("diamond_color[]="+colorItem.getValue()+"&");
                        Log.e("arrayListColor","---------"+arrayListColor);
                    }


                }
            });

        }

        @Override
        public int getItemCount() {

            return itemArrayList.size();
        }

        public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

            private Button button_color;

            public ViewHolder(View itemView) {
                super(itemView);
                itemView.setOnClickListener(this);
                button_color = (Button) itemView.findViewById(R.id.button_color);

            }

            @Override
            public void onClick(View v) {

            }

        }

    }

Answer 3

创建那些提到的自定义多 select 实现工作正常，但当数据集很大时可能会出现性能问题。我强烈建议阅读 google 的 Advanced RecyclerView customization 文档。

Answer 4

无需创建模型 class 我们可以在 recyclerview 中添加多个 select 项目。在 recyclerview 适配器中使用此代码

holder.favplayIcon.setOnClickListener(View.OnClickListener {
                    if (!row_index.contains(position)) {
                        row_index.add(position)
                        holder.favplayIcon.setImageDrawable(
                            ResourcesCompat.getDrawable(resources, R.drawable.ic_starfilled, null ))

                    } else {
                        row_index.removeAt(row_index.indexOf(position))
                        holder.favplayIcon.setImageDrawable(
                   ResourcesCompat.getDrawable(resources,R.drawable.ic_starborder, null)
                        )  }
                })

///// put below code out of onclicklistener method of item
                if (!row_index.contains(position)) {

                    holder.favplayIcon.setImageDrawable(
                        ResourcesCompat.getDrawable(
                            resources,
                            R.drawable.ic_starborder,
                            null
                        )
                    )
} else {
                    holder.favplayIcon.setImageDrawable(
                        ResourcesCompat.getDrawable(
                            resources,
                            R.drawable.ic_starfilled,
                            null
                        )
                    )

Answer 5

简单快捷的方法：

  holder.parentLayout.setOnClickListener {

        if (holder.categoryIcon.isSelected) {
            selectedPos = position
        }

        if (selectedPos == position) {
            notifyItemChanged(selectedPos)
            selectedPos = RecyclerView.NO_POSITION
        } else {
            selectedPos = position
            notifyItemChanged(selectedPos)
        }
    }


    if (selectedPos == position) {
        holder.categoryIcon.setBackgroundColor(ContextCompat.getColor(context, R.color.orange))
        holder.categoryIcon.isSelected = true
    } else {
        holder.categoryIcon.setBackgroundColor(ContextCompat.getColor(context, R.color.white))
        holder.categoryIcon.isSelected = false
    }

RecyclerView中如何实现multi-select？

How to implement multi-select in RecyclerView?

android

android-recyclerview

multi-select