如何根据特定条件在我的 RecyclerView 上隐藏某些项目的 ImageView？

问题描述

我有一个 RecyclerView，其中一个 ImageView 是项目的一部分。如果满足特定条件，我想从 RecyclerView 中的项目中隐藏 ImageView。我怎样才能做到这一点？我附上了我想要的样子的图像。

我只是在我的 xml 布局文件中定义 ImageViews，所以我无法根据我的 android 活动中的特定条件弄清楚如何实际删除它。我还附上了适配器类和我的活动的代码。

这是我的适配器类的代码

适配器类

the name `T` is already used for a generic parameter

这是我的活动文件的代码

活动文件

public class ReportAdapter extends RecyclerView.Adapter<ReportAdapter.ReportViewHolder> {

    private ArrayList<ReportItem> reportlist;
    private OnItemClickListener mListener;
    private Context mContext;

    public ReportAdapter(ArrayList<ReportItem> reportlist,Context context) {
        this.reportlist = reportlist;
        this.mContext = context;
    }

    public interface OnItemClickListener {
        void onItemClick(int position);
    }

    public void setonItemClickListener(OnItemClickListener listener) {
        mListener = listener;
    }

    public static class ReportViewHolder extends RecyclerView.ViewHolder {

        public TextView departureDate;
        public TextView flightNumber;
        public View relativelayout;

        public ReportViewHolder(@NonNull View itemView,OnItemClickListener listener,Context context) {
            super(itemView);

            departureDate = itemView.findViewById(R.id.departureDaterecyclerview);
            flightNumber =  itemView.findViewById(R.id.flightnumberrecyclerview);
            relativelayout = itemView.findViewById(R.id.relativeLayoutReports);

            itemView.setonClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(listener != null) {
                        int position = getAdapterPosition();
                        if(position != RecyclerView.NO_POSITION) {
                            listener.onItemClick(position);


                        }
                    }

                }
            });
        }
    }

    @NonNull
    @Override
    public ReportViewHolder onCreateViewHolder(@NonNull ViewGroup parent,int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.report_listing_item,parent,false);
        ReportViewHolder rvh= new ReportViewHolder(v,mListener,mContext);
        return rvh;
    }

    @SuppressLint("ResourceAsColor")
    @Override
    public void onBindViewHolder(@NonNull ReportViewHolder holder,int position) {

        ReportItem currentItem = reportlist.get(position);

        if(position%2==0){
            holder.relativelayout.setBackgroundColor(mContext.getResources().getColor(R.color.reportlistingteal));

        } else {
            holder.relativelayout.setBackgroundColor(mContext.getResources().getColor(R.color.reportlistinglightteal));
        }
        holder.departureDate.setText((currentItem.getDepartureDate()));
        holder.flightNumber.setText(currentItem.getFlightNumber());
    }

报告项目

public class ReportListingActivity extends AppCompatActivity {

    private Button uploadAllBtn;
    private EditText searchFlights;
    private RecyclerView mRecyclerView;
    private ReportAdapter mAdapter;
    private RecyclerView.LayoutManager mLayoutManager;

    ArrayList<ReportItem> reportitems = new ArrayList<>();
    private Flightviewmodel flightviewmodel;


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

        uploadAllBtn = findViewById(R.id.uploadAllReports);
        searchFlights = findViewById(R.id.searchFlightText);
        mRecyclerView = findViewById(R.id.recyclerView);


        flightviewmodel = new viewmodelProvider(this).get(Flightviewmodel.class);

        flightviewmodel.getAllFlights().observe(this,new Observer<List<Flight>>() {
            @Override
            public void onChanged(List<Flight> flight_list) {

                if (flight_list.size() == 0) return;

                String flightno = flight_list.get(0).getFlightNumber();
                String flightdate = flight_list.get(0).getDate();

                String[] flight_details = new String[2];
                flight_details[0]= flightno;
                flight_details[1] = flightdate;

                Log.v("pp",flight_details[0]);

                for(int i = 0; i <flight_list.size();i++){
                    String flightnumber = flight_list.get(i).getFlightNumber();
                    String departuredate = flight_list.get(i).getDate();
                    

                    reportitems.add(new ReportItem(flightnumber,departuredate));

                    
                }
                mRecyclerView.getAdapter().notifyDataSetChanged();
                flightviewmodel.getAllFlights().removeObservers(ReportListingActivity.this);
            }
        });

        mLayoutManager = new linearlayoutmanager(ReportListingActivity.this);
        mAdapter = new ReportAdapter(reportitems,ReportListingActivity.this);

        mRecyclerView.setLayoutManager(mLayoutManager);
        mRecyclerView.setAdapter(mAdapter);

    }

解决方法

为每个 RecyclerView 项目向 ReportItem 类添加一个布尔标志。创建每个项目时，您需要指定哪些行显示或隐藏此字段：

public class ReportItem {

    private String departureDate;
    private String flightNumber;
    private Boolean showMailIcon;

    public ReportItem(String departureDate,String flightNumber,Boolean showMailIcon) {
        this.departureDate = departureDate;
        this.flightNumber = flightNumber;
        this.showMailIcon = showMailIcon
    }

    public String getDepartureDate() {
        return departureDate;
    }

    public String getFlightNumber() {
        return flightNumber;
    }

    public String getShowMailIcon() {
        return showMailIcon;
    }
}

然后更新 onBindViewHolder() 方法覆盖以使用此标志来显示/隐藏 ImageView：

@Override
public void onBindViewHolder(@NonNull ReportViewHolder holder,int position) {

    ReportItem currentItem = reportlist.get(position);
  
    if (currentItem.getShowMailIcon() == true) {
        holder.mailIcon.setVisibility(View.VISIBLE);
    } else {
        holder.mailIcon.setVisibility(View.GONE);
    }
  

    //.......
}