java - 单击 recyclerAdapter 在大型数据集上工作很奇怪，但在小型数据集上工作正常

Question

我有一个回收服务适配器， View 是某种复杂的按钮，它是从一些 xml 文件创建的:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/services_container"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="20dp"
    android:layout_marginRight="20dp"
    android:layout_marginStart="20dp"
    android:layout_marginTop="15dp"
    android:gravity="center_horizontal"
    android:orientation="vertical">

    <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:id="@+id/services_place_holder"
        android:layout_width="@dimen/viewPlaceHolderWidth_services"
        android:layout_height="@dimen/viewPlaceHolderHeight_services"
        android:layout_marginTop="10dp"
        android:background="@drawable/rounded_view_selector_services"
        android:focusable="false"
        android:gravity="center_horizontal"
        android:orientation="vertical"
        app:layout_constraintTop_toTopOf="@id/services_container">

        <TextView
            android:id="@+id/service_price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="16dp"
            android:background="@drawable/rounded_text_view_for_services"
            android:paddingBottom="2dp"
            android:paddingLeft="10dp"
            android:paddingRight="10dp"
            android:paddingTop="2dp"
            android:text="۲۳۲۲۲۳۵۶۶"
            android:textAlignment="center"
            android:textColor="@color/colorWhite"
            android:textSize="12sp"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <ImageView
            android:id="@+id/service_image"
            android:layout_width="38dp"
            android:layout_height="38dp"
            android:layout_marginEnd="8dp"
            android:layout_marginStart="8dp"
            android:layout_marginTop="6dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/service_price"
            app:srcCompat="@drawable/placeholder_blue" />

        <me.grantland.widget.AutofitTextView
            android:id="@+id/service_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="11dp"
            android:layout_marginStart="11dp"
            android:layout_marginTop="2dp"
            android:layout_marginBottom="2dp"
            android:paddingLeft="8dp"
            android:paddingRight="8dp"
            android:maxLines="1"
            android:text="پرستار"
            android:textColor="@color/colorElahiyeBlue"
            android:textSize="18sp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/service_image"
            app:minTextSize="6sp" />
    </android.support.constraint.ConstraintLayout>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="-120dp"
        android:orientation="horizontal">

        <ImageView
            android:id="@+id/services_gender_image"
            android:layout_width="20dp"
            android:layout_height="20dp"
            android:src="@drawable/available_gender" />

        <ImageView
            android:id="@+id/services_prescription_image"
            android:layout_width="20dp"
            android:layout_height="20dp"
            android:layout_marginLeft="7dp"
            android:layout_marginStart="7dp"
            android:src="@drawable/available_picture" />

        <ImageView
            android:id="@+id/services_info_image"
            android:layout_width="20dp"
            android:layout_height="20dp"
            android:layout_marginLeft="7dp"
            android:layout_marginStart="7dp"
            android:src="@drawable/info" />
    </LinearLayout>
</LinearLayout>

我有一个处理其中点击事件的服务适配器，数据集是使用改造从网络服务加载的，这没有问题，但我的问题是我想点击每个项目的背景和一些其他 UI 和它们的位置要更改和存储，当数据集低于 4 时一切正常，但是当数据集大约为 6 或更多时，会出现一些奇怪的行为，例如:当我单击一个项目时，另一个项目是clicked ，我管理点击的方式是通过我的 View Layout "services_container"或 "services_place_holder"的 isFocusable ，适配器代码在这里:

public class ServicesAdapter extends RecyclerView.Adapter<ServicesAdapter.ViewHolder> {

    private List<Integer> selectedServices = new ArrayList<>();
    private LayoutInflater mInflater;
    private ItemClickListener mClickListener;
    private Context mContext;
    private int row_index = -1;

    // data is passed into the constructor
//    public FieldOfEmploymentAdapter(Context context, List<Integer> colors, List<String> servicesDataItemsList) {
    ServicesAdapter(Context context, List<ServicesDataItems> servicesDataItemsList) {
        mContext = context;
        this.mInflater = LayoutInflater.from(context);
//        this.mViewColors = colors;
        this.servicesDataItemsList = servicesDataItemsList;
    }

    // inflates the row layout from xml when needed
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = mInflater.inflate(R.layout.services_items, parent, false);
        ViewHolder viewHolder = new ViewHolder(view);
        return viewHolder;
    }

    // binds the data to the view and textview in each row
    @Override
    public void onBindViewHolder(final ViewHolder holder, final int position) {
//        int color = mViewColors.get(position);
        final ServicesDataItems servicesDataItems = servicesDataItemsList.get(position);
        holder.linLayout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                row_index = position;
                notifyDataSetChanged();
            }
        });

        if (row_index == position) {
            Toast.makeText(mContext, "Pos: " + position + " , GetAdapterPos: " + holder.getAdapterPosition(), Toast.LENGTH_SHORT).show();

            //                Toast.makeText(mContext, "SSSS" + MainActivity.servicesNumber.getText().toString(), Toast.LENGTH_SHORT).show();
            int servicesNumber = Integer.parseInt(MainActivity.servicesNumber.getText().toString());


//                Toast.makeText(mContext, "is instance of BitmapDrawable= " + holder.constraintLayout.isFocusable() + "    ======     ", Toast.LENGTH_SHORT).show();
            if (holder.linLayout.isSelected()){
                Toast.makeText(mContext, "IsSelected ", Toast.LENGTH_SHORT).show();
            }
            if (holder.linLayout.isFocusable()) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                    holder.constraintLayout.setBackground(ContextCompat.getDrawable(mContext, R.drawable.rounded_view_selector_services));
                    holder.linLayout.setFocusable(false);
                    MainActivity.servicesNumber.setText(String.valueOf(--servicesNumber));
                    removeSelectedService(position);

                } else {
                    holder.constraintLayout.setBackgroundDrawable(ContextCompat.getDrawable(mContext, R.drawable.rounded_view_selector_services));
                    holder.linLayout.setFocusable(false);
                    MainActivity.servicesNumber.setText(String.valueOf(--servicesNumber));
                    removeSelectedService(position);
                }
            } else {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                    holder.constraintLayout.setBackground(ContextCompat.getDrawable(mContext, R.drawable.rounded_view_selector_services_selected));
                    holder.linLayout.setFocusable(true);
                    MainActivity.servicesNumber.setText(String.valueOf(++servicesNumber));
                    selectedServices.add(position);
                } else {
                    holder.constraintLayout.setBackgroundDrawable(ContextCompat.getDrawable(mContext, R.drawable.rounded_view_selector_services_selected));
                    holder.linLayout.setFocusable(true);
                    MainActivity.servicesNumber.setText(String.valueOf(++servicesNumber));
                    selectedServices.add(position);
                }
            }

            if (servicesNumber > 0) {
                Drawable selectLocation = ContextCompat.getDrawable(mContext, R.drawable.rbtn_location_active);
                ColorStateList colorStateList = ContextCompat.getColorStateList(mContext, R.color.rbtn_text_color_button);
                new EnableLocationSelectButton(selectLocation, colorStateList).invoke();
            }

            if (servicesNumber == 0) {
                Drawable selectLocation = ContextCompat.getDrawable(mContext, R.drawable.rbtn_location_dimmed);
                ColorStateList colorStateList = ContextCompat.getColorStateList(mContext, R.color.ElahiyeGray);
                new DisableLocationSelectButton(selectLocation, colorStateList).invoke();
            }

            boolean isPrescriptionImageVisible = false;
            boolean isGenderImageVisible = false;

            for (int selected : selectedServices) {
                if (servicesDataItemsList.get(selected).has_prescriptions_image()) {
                    isPrescriptionImageVisible = true;
                    if (MainActivity.prescriptionImageHolder.getVisibility() == View.INVISIBLE) {
                        MainActivity.gender_prescription_selection.setVisibility(View.VISIBLE);
                        MainActivity.gender_prescription_separator.setVisibility(View.VISIBLE);
                        MainActivity.doctorPrescription.setVisibility(View.VISIBLE);
                    }
                }

                if (servicesDataItemsList.get(selected).hasGender()) {
                    isGenderImageVisible = true;
                    MainActivity.gender_prescription_selection.setVisibility(View.VISIBLE);
                    MainActivity.gender_prescription_separator.setVisibility(View.VISIBLE);
                    MainActivity.genderSelection.setVisibility(View.VISIBLE);
                }
            }

            if (!isPrescriptionImageVisible) {
                MainActivity.doctorPrescription.setVisibility(View.INVISIBLE);
                MainActivity.prescriptionImageHolder.setVisibility(View.INVISIBLE);
            }

            if (!isGenderImageVisible) {
                MainActivity.genderSelection.setVisibility(View.INVISIBLE);
            }

            if (!isPrescriptionImageVisible && !isGenderImageVisible) {

                MainActivity.gender_prescription_selection.setVisibility(View.INVISIBLE);
                MainActivity.gender_prescription_separator.setVisibility(View.INVISIBLE);
            }
        }
        holder.service_name.setText(servicesDataItems.getServices_name());
        holder.service_price.setText(servicesDataItems.getServices_price());
    }

    private void removeSelectedService(int position) {
        int index = 0;
        for (int selected : selectedServices) {
            if (selected == position) {
                selectedServices.remove(index);
                return;
            }
            index++;
        }
    }

    // total number of rows
    @Override
    public int getItemCount() {
        return servicesDataItemsList.size();
    }

    // stores and recycles views as they are scrolled off screen
    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        //        ImageView myImageView;
        TextView service_name;
        TextView service_price;
        ConstraintLayout constraintLayout;
        LinearLayout linLayout;
        ImageView serviceGender;
        ImageView servicePrescription;

        ViewHolder(View itemView) {
            super(itemView);
//            myImageView = itemView.findViewById(R.id.service_image);
            service_name = itemView.findViewById(R.id.service_name);
            service_price = itemView.findViewById(R.id.service_price);
            constraintLayout = itemView.findViewById(R.id.services_place_holder);
            linLayout = itemView.findViewById(R.id.services_container);
            serviceGender = itemView.findViewById(R.id.services_gender_image);
            servicePrescription = itemView.findViewById(R.id.services_prescription_image);
            itemView.setOnClickListener(this);
        }
}

请告诉我如何正确管理每个项目的 OnClick 监听器？我还阅读了所有其他主题，但没有一个对我有帮助。

Answer 1

我已经查看了您的代码，我想我已经找到了问题所在。您有一个条件，您可以检查 row_index 是否等于 position。但是，我没有看到此声明的任何其他部分。

当您的数据集很小时，它可以工作，小到您不必滚动它。但是，当您的数据集很大并且您必须滚动它时，它应该有一些随机行为，因为您没有指定语句的 else 部分。每次滚动时 View 都会被回收，并且在实现 onBindViewHolder 函数时，您需要准确地告诉每行要加载的内容。

因此，我建议您即使不满足条件(即 else 部分)也对 holder 项目进行分配。

if (row_index == position) {
    // Your current implementation
} else {
    // Set the views accordingly when the above condition is not met.
}

更新

如果你想在你的 RecyclerView 中实现多个项目选择，那么你可能需要保留一个单独的数组来跟踪所选项目，然后根据轨道回收项目你保存在你的数组中。例如，让我们考虑一个数组来跟踪点击。

public int[] clickTrack = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

现在，当您单击一个项目时，只需将单击的轨迹保存到您的数组中。

@override 
public void onClick(View v) {
    if(clickTrack[position] == 0) clickTrack[position] = 1;
    else clickTrack[position] = 0;

    notifyDataSetChanged();
}

现在，当您已经单击了一些项目时，数组将看起来像这样。

{0, 1, 0, 1, 1, 0, 1, 0, 1, 0}

在您的 onBindViewHolder 中，只需根据您在跟踪点击的数组中找到的值展开项目。

if(clickTrack[position] == 1) someView.expand();
else someView.collapse();

这是一个示例实现。我希望你明白了。这是一个 nice answer实现相同。你也可以考虑去那里看看。