android – 如何在RecyclerView中实现多选？

ListView有一个多选模式,我应该用什么来实现使用RecyclerView？如何处理onItemCheckedStateChanged？
我查了this,
但是我无法理解这一点.任何代码片段或实现它的示例项目都会很棒.提前致谢.

解决方法:

我知道回答这个问题有点晚了.我不知道它是否符合OP的要求.但这可能对某人有所帮助.我用一个简单的技巧实现了这个多选RectyclerView.这是我的代码.

activity_main.xml中

<?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,它从ArrayList获取单个对象,Model model = mModelList.get(position);目前的位置.现在我们需要检查是否选择了特定对象.像这样,

model.isSelected()

返回true或false.如果已经选择了该对象,我们需要更改所选row_item的背景颜色.为此,这里是代码

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

如果选择它,则将背景颜色更改为青色,否则为白色.

为了选择,我们需要使用setOnClickListener()方法. (这里我只使用TextView.所以我在TextView上执行click事件).这里holder.view表示整个single item_row. Onclick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,您可以获取所选的对象/项目

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

这是输出

编辑1：限制用户只选择一个项目.

 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();  
        }
    });
}

我希望它会有所帮助.

标签：android,android-recyclerview,multi-select
来源： https://codeday.me/bug/20190916/1808044.html