Question

我想实现带有水平和垂直滚动的RecyclerView以及垂直项目上的一个按钮，所以当我点击按钮时，应该将文本更改为保存到已保存。在我的应用程序中，当我单击按钮时，文本被更改但是当我自动向下滚动时，另一个按钮的文本被更改。以下是我的代码。

In this screenshot I clicked on VerticalList3's button and text is changed successfully

When I scrolled down automatically VerticalList20 and VerticalList14's button text is changed

 public class MainActivity extends AppCompatActivity {
private RecyclerView vertical_recycler_view,horizontal_recycler_view;
private ArrayList<String> horizontalList,verticalList;
private HorizontalAdapter horizontalAdapter;
private  VerticalAdapter verticalAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    vertical_recycler_view= (RecyclerView) findViewById(R.id.vertical_recycler_view);
    horizontal_recycler_view= (RecyclerView) findViewById(R.id.horizontal_recycler_view);



    horizontalList=new ArrayList<>();
    horizontalList.add("horizontal 1");
    horizontalList.add("horizontal 2");
    horizontalList.add("horizontal 3");
    horizontalList.add("horizontal 4");
    horizontalList.add("horizontal 5");
    horizontalList.add("horizontal 6");
    horizontalList.add("horizontal 7");
    horizontalList.add("horizontal 8");
    horizontalList.add("horizontal 9");
    horizontalList.add("horizontal 10");
    horizontalList.add("horizontal 11");
    horizontalList.add("horizontal 12");
    horizontalList.add("horizontal 13");
    horizontalList.add("horizontal 14");
    horizontalList.add("horizontal 15");
    horizontalList.add("horizontal 16");
    horizontalList.add("horizontal 17");
    horizontalList.add("horizontal 18");
    horizontalList.add("horizontal 19");
    horizontalList.add("horizontal 20");


    verticalList=new ArrayList<>();
    verticalList.add("verticallist 1");
    verticalList.add("verticallist 2");
    verticalList.add("verticallist 3");
    verticalList.add("verticallist 4");
    verticalList.add("verticallist 5");
    verticalList.add("verticallist 6");
    verticalList.add("verticallist 7");
    verticalList.add("verticallist 8");
    verticalList.add("verticallist 9");
    verticalList.add("verticallist 10");
    verticalList.add("verticallist 11");
    verticalList.add("verticallist 12");
    verticalList.add("verticallist 13");
    verticalList.add("verticallist 14");
    verticalList.add("verticallist 15");
    verticalList.add("verticallist 16");
    verticalList.add("verticallist 17");
    verticalList.add("verticallist 18");
    verticalList.add("verticallist 19");
    verticalList.add("verticallist 20");

    horizontalAdapter=new HorizontalAdapter(horizontalList);
          verticalAdapter=new VerticalAdapter(verticalList);


    LinearLayoutManager verticalLayoutmanager
            = new LinearLayoutManager(MainActivity.this, 
LinearLayoutManager.VERTICAL, false);
    vertical_recycler_view.setLayoutManager(verticalLayoutmanager);
//        RecyclerView.LayoutManager mLayoutManager = new 
LinearLayoutManager(getApplicationContext());
//        vertical_recycler_view.setLayoutManager(mLayoutManager);
    LinearLayoutManager horizontalLayoutManagaer
            = new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false);
    horizontal_recycler_view.setLayoutManager(horizontalLayoutManagaer);

    vertical_recycler_view.setAdapter(verticalAdapter);
    horizontal_recycler_view.setAdapter(horizontalAdapter);
}



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

    private List<String> horizontalList;

    public class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView txtView;

        public MyViewHolder(View view) {
            super(view);
            txtView = (TextView) view.findViewById(R.id.txtView);
        }
    }


    public HorizontalAdapter(List<String> horizontalList) {
        this.horizontalList = horizontalList;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.horizontal_item_view, parent, false);

        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {

        holder.txtView.setText(horizontalList.get(position));
        holder.txtView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this,holder.txtView.getText().toString(),Toast.LENGTH_SHORT).show();
            }
        });
    }

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



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

    private List<String> verticalList;

    public class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView txtView;
        public Button button;
        public MyViewHolder(View view) {
            super(view);
            txtView = (TextView) view.findViewById(R.id.txtView);
            button = (Button) view.findViewById(R.id.verticalButton);
        }
    }


    public VerticalAdapter(List<String> verticalList) {
        this.verticalList = verticalList;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.vertical_item_view, parent, false);

        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {
        holder.button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                holder.button.setText("Saved");
            }
        });
        holder.txtView.setText(verticalList.get(position));
        holder.txtView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Toast.makeText(MainActivity.this,holder.txtView.getText().toString(),Toast.LENGTH_SHORT).show();
            }
        });
    }

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

Answer 1

@Potapov Anton是对的，但你也可以这样做。

实施此方法：

@Override
public int getItemViewType(int position) {
    return position;
}

希望有所帮助

Answer 2

RecyclerView将viewHolder重用于其他项目。因此，仅在viewHolder中将文本直接设置为按钮（如此holder.button.setText("Saved");）是错误的。您需要在列表中为此位置的项目设置文本。

Answer 3

您还必须存储按钮的状态。您可以创建另一个列表：

List<Boolean> buttonsStatus = new ArrayList<>(numOfElements);

和填写清单：

for(int i = 0; i<numOfElements; i++)
{
     buttonsStatus.add(false)
}

或者您可以修改当前列表以存储Item个对象，如下所示：

public class Item{
     public String text
     public boolean saved;
     public Item(String text, boolean saved)
     {
          this.text = text;
          this.saved= saved;
     }
}

并在您的代码中使用它：

List<Item> verticalList = new ArrayList<>();
verticalList.add(new Item("verticallist 1", false));
...

并在onBindViewHolder方法中：

@Override
public void onBindViewHolder(final MyViewHolder holder, final int position) {
    holder.button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            holder.button.setText("Saved");
            verticalList.get(position).saved = true;
        }
    });
    Item item = verticalList.get(position);
    holder.button.setText(item.saved ? "Saved" : "Save");
    holder.txtView.setText(item.text);
    holder.txtView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Toast.makeText(MainActivity.this,holder.txtView.getText().toString(),Toast.LENGTH_SHORT).show();
        }
    });
}

我有一个关于使用水平和垂直滚动实现RecyclerView的问题

3 个答案: