Question

我有一个RecyclerView，其中包含JSON中本地CardView的数据。我需要在单击某个或某个项目时更改所选项目（更改背景项目选中或突出显示）（如在线应用程序中编辑）但不使用按钮或longpress。但我不想使用StateListDrawable或（使用XML）因为我有一些JSON数据需要稍后处理。

我需要在我的Activity中使用一个状态，比如一个布尔值或某些东西来保存我点击的每个项目，但我再也没有任何解决方案了。我已阅读并尝试了一些教程，但它无法正常工作。现在低于我的活动：

adapter.setOnRecyclerViewClickedListener(new Adapter.OnRecyclerViewItemClickedListener() {
        @Override
        public void OnRecyclerViewItemClicked(int position) {
            boolean selectedItem = false;

            adapter.setOnRecyclerViewClickedListener(new Adapter.OnRecyclerViewItemClickedListener() {

        @Override
        public void OnRecyclerViewItemClicked(int position)  {

    /* ------ boolean variabel for adapter but still not work ----- */
            JSONObject filteredtableList= null;

            try {
                filteredtableList= new JSONObject("response").getJSONObject("tTisch");
            }
            catch (JSONException e) {
                e.printStackTrace();
            }

                if (recyclerView == null) {
                    try {
                        filteredtableList.has("true");
                        filteredtableList.put(status, true);
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
                else {
                    try {
                        filteredtableList.put(status, true);

                    }
                    catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            adapter.updateData(filteredTableList);

//----------------------------------------------------
            try {
                Toast.makeText(TableActivity.this, filteredTableList.getJSONObject(position).getString("tischnr"), Toast.LENGTH_SHORT).show();
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    });

Adapter.java

public int lastCheckedPosition = -1;
.........
.........
.........
    @Override
public void onBindViewHolder(ViewHolder holder, int position) {

    if (position == lastCheckedPosition) {
        holder.itemView.setBackgroundResource(R.color.colorRedTableOcc);
    } else {
        holder.itemView.setBackgroundResource(R.color.colorTableGreen);
    }

    try {
        currItem = list.getJSONObject(position);
        holder.txt_no_table.setText(currItem.getString("tischnr"));

    } catch (JSONException e) {
        e.printStackTrace();
    }
}


@Override
public int getItemCount() {
    return list.length();
}

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

    public TextView txt_no_table;

    public ViewHolder(View itemView) {
        super(itemView);
        itemView.setOnClickListener(this);

        txt_no_table = (TextView) itemView.findViewById(R.id.txt_no_table_empty);
    }

    @Override
    public void onClick(View itemView) {

        recyclerViewItemClickedListener.OnRecyclerViewItemClicked(getAdapterPosition());

        lastCheckedPosition = getAdapterPosition();
        notifyItemRangeChanged(0,list.length());
    }
}

JSON.json

..............
"t-tisch": [
            {
                "tischnr": 1,
                "departement": 1,
                "normalbeleg": 0,
                "kellner-nr": 0,
                "bezeich": "TABLE 01",
                "roomcharge": false,
                "betriebsnr": 0
            },
            {
                "tischnr": 2,
                "departement": 1,
                "normalbeleg": 0,
                "kellner-nr": 0,
                "bezeich": "TABLE 02",
                "roomcharge": false,
                "betriebsnr": 0
            },
............

这是我的活动看起来像

更新

立即输出：

当我点击该项目时，它现在突出显示（感谢@Burhanuddin Rashid），但它仍然是我案例的一半。我只能选择一个项目（我无法选择多个/多个项目）。当我点击突出显示项目时，我需要再次取消选择。

编辑：我尝试在我的JSON（上面的JSON代码）中编写新对象和密钥。在我的逻辑中，它会为每个项目选择与否制作一个标志，但它仍然不起作用。

已编辑：这是我的日志错误：

                  --------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.example.development_laptop.vhp_restotemp, PID: 3590
              java.lang.NullPointerException: Attempt to invoke virtual method 'org.json.JSONObject org.json.JSONObject.put(java.lang.String, boolean)' on a null object reference
                  at com.example.development_laptop.vhp_restotemp.TableActivity$1.OnRecyclerViewItemClicked(TableActivity.java:74)
                  at com.example.development_laptop.vhp_restotemp.com.example.development_laptop.vhp_restotemp.recyclerview.source.Adapter$ViewHolder.onClick(Adapter.java:97)
                  at android.view.View.performClick(View.java:5198)
                  at android.view.View$PerformClick.run(View.java:21147)
                  at android.os.Handler.handleCallback(Handler.java:739)
                  at android.os.Handler.dispatchMessage(Handler.java:95)
                  at android.os.Looper.loop(Looper.java:148)
                  at android.app.ActivityThread.main(ActivityThread.java:5417)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

Answer 1

您可以像这样应用setOnClickListener： -

View itemView;
    Context context;


    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
         itemView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.card_view, parent, false);
        this.context=parent.getContext();
        return new ViewHolder(itemView);
    }
    @Override
        public void onBindViewHolder(final ViewHolder holder, int position) {

            holder.itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                        holder.linearLayout.setBackgroundColor(context.getResources().getColor(R.color.colorAccent,null));
                    }
                    else {
                        holder.linearLayout.setBackgroundColor(context.getResources().getColor(R.color.colorAccent));

                    }
                }
            });
        }

Answer 2

试试这个：

<强> onBindViewHolder：

if (position == lastCheckedPosition) {
            holder.itemView.setBackgroundResource(R.drawable.ic_item_selection_background);
        } else {
            holder.itemView.setBackgroundResource(R.drawable.ic_item_deselection_background));
        }

这是 ViewHolder ：

    itemView.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        lastCheckedPosition = getAdapterPosition();
                         notifyItemRangeChanged(0,getItemCount());
                     }
                });

创建lastCheckedPosition作为全局变量

Answer 3

遵循以下准则：

将此代码放入onBindViewHolder()方法中。

  @Override
    public void onBindViewHolder(final ViewHolder holder, final int position) {
    final DataModel dataModel = arraylist.get(position);
            final boolean isSelected = dataModel.isSelected();
            if (isSelected) {
               llParentLayout.setBackgroundColor(Color.Black);
            } else {
               llParentLayout.setBackgroundColor(Color.Green);            
            }
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    public TextView txt_no_table;
    public ViewHolder(View itemView) {
        super(itemView);
        itemView.setOnClickListener(this);

        txt_no_table = (TextView) itemView.findViewById(R.id.txt_no_table_empty);
    }

    @Override
    public void onClick(View itemView) {
final DataModel dataModel = arraylist.get(getAdapterPosition());
        recyclerViewItemClickedListener.OnRecyclerViewItemClicked(dataModel);

    }
}

在您的活动中：

adapter.setOnRecyclerViewClickedListener(new Adapter.OnRecyclerViewItemClickedListener() {
        @Override
        public void OnRecyclerViewItemClicked(DataModel dataModel) {

dataModel.setSelected(!dataModel.isSelected());
adapter.notifyDataSetChanged();


        }
    });

Answer 4

我完全改变了我的代码，但现在它的功能很强大，我的代码看起来像这样：

我将Adapter更改为通用适配器。它不会处理任何数据，但它会引发我的活动。

public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
public int lastCheckedPosition = -1;

private static OnRecyclerViewItemClickedListener recyclerViewItemClickedListener;

public void setOnRecyclerViewClickedListener (OnRecyclerViewItemClickedListener l) {
recyclerViewItemClickedListener = l;
}

public interface OnRecyclerViewItemClickedListener {
  void OnRecyclerViewItemClicked(int position);
  void OnRecyclerViewItemBind(ViewHolder holder, int position);
  int OnRecyclerViewItemCount();

}
public Adapter() {
  super();
} 

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

@Override
public void onBindViewHolder(ViewHolder holder, int position) {
recyclerViewItemClickedListener.OnRecyclerViewItemBind(holder,position);
}

@Override
public int getItemCount() {
  return recyclerViewItemClickedListener.OnRecyclerViewItemCount();
}

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

public TextView txt_no_table;

public ViewHolder(View itemView) {
    super(itemView);
    itemView.setOnClickListener(this);

    txt_no_table = (TextView) itemView.findViewById(R.id.txt_no_table_empty);
}

@Override
public void onClick(View itemView) {

    recyclerViewItemClickedListener.OnRecyclerViewItemClicked(getAdapterPosition());
     }
   }
}

我的Activity变成了这样：

/*Add Click Listener*/
adapter.setOnRecyclerViewClickedListener(new Adapter.OnRecyclerViewItemClickedListener() {

    @Override
    public void OnRecyclerViewItemClicked(int position)  {
        try {
            JSONObject currTable = filteredTableList.getJSONObject(position);

            if (currTable.has("selected")) {
                currTable.put("selected", !currTable.getBoolean("selected"));
            } else {
                currTable.put("selected",true);
            }

            adapter.notifyItemChanged(position);
        } catch (JSONException e) {
            e.printStackTrace();
        }

        try
        {
            Toast.makeText(TableActivity.this, filteredTableList.getJSONObject(position).getString("tischnr"), Toast.LENGTH_SHORT).show();
        }
        catch (JSONException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void OnRecyclerViewItemBind(Adapter.ViewHolder holder, int position) {
        try {
            JSONObject currTable = filteredTableList.getJSONObject(position);

            holder.txt_no_table.setText(currTable.getString("tischnr"));

            int queasy33Index = ProgramMethod.getJSONArrayIndex(queasy33List,"number2", currTable.getInt("tischnr"));

            if (queasy33Index >= 0) {
                holder.txt_no_table.setText(holder.txt_no_table.getText() + "-" +  queasy33List.getJSONObject(queasy33Index).getString("key"));
            }

            if (currTable.has("selected") && currTable.getBoolean("selected")) {
                holder.itemView.setBackgroundResource(R.color.colorRedTableOcc);
            } else {
                holder.itemView.setBackgroundResource(R.color.colorTableGreen);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

现在点击监听器保存任何状态并保存到我的JSON文件中的布尔值，如下所示：

感谢大家的建议和很好的答案：）

Answer 5

尝试以下代码

内

public Adapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)

把

View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_image_and_text, parent, false);
v.setOnClickListener(new MyOnClickListener());

在任何你想要的地方创建这个类

class MyOnClickListener implements View.OnClickListener {
    @Override
    public void onClick(View v) {
       int itemPosition = recyclerView.indexOfChild(v);
       Log.e("Clicked and Position is ",String.valueOf(itemPosition));
    }
}

之前我读过有更好的方法，但我喜欢这种方式很容易而且不复杂。

Answer 6

以上都是非常好的答案，但我相信你会选择这个这为您提供了比其他人更多的灵活性

document.getElementById('divElem').scrollIntoView();

Activity.java中的多个选定项目RecyclerView

更新

6 个答案: