Activity.java中的多个选定项目RecyclerView

Question

Activity.java中的多个选定项目RecyclerView

MrX*_*MrX 8 java android json android-recyclerview

我有一个RecyclerView从本地数据JSON在CardView.我需要在单击一个或多个项目时更改所选项目(更改背景项目选择或突出显示)(如在线应用程序中编辑)但不使用Button或longpress.但我不想使用StateListDrawable或(使用XML),因为我有一些JSON需要稍后处理的数据.

我需要一个状态在我的Activity中像一个布尔值或者某些东西来保存我点击的每个项目,但我没有任何解决方案.我已阅读并尝试了一些教程,但它不起作用.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();
            }
        }
    });

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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());
    }
}

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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
            },
............

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这是我的活动看起来像

更新

现在输出:

现在点击该项目时突出显示(感谢@Burhanuddin Rashid),但它仍然是我案例的一半.我只能选择一个项目(我不能选择多个/多个项目).单击突出显示项目时,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,它将为每个项目选择与否制作一个标志,但它仍然不起作用.

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)

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Answer 1

MrX*_*MrX 1

我完全改变了我的代码，但它现在功能强大，我的代码如下所示：

我将其更改Adapter为通用适配器。它不处理任何数据，但它会抛出到我的活动中。

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());
     }
   }
}

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我的Activity变成这样：

/*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();
        }
    }

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现在，点击侦听器保存任何状态并保存到我的 JSON 文件中的布尔值中，如下所示：

感谢大家提出的建议和很好的答案:)

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