Android 如何在Recyclerview中使用微调器？

在

RecyclerView

适配器中处理微调器的最佳实践是什么

这是我的

RecyclerView

适配器：

public class CartAdapter extends BaseAdapter<Object> {

public CartAdapter(AbstractBaseActivity activity) {
    super(activity);
}

public static final int TYPE_PRODOTTO = 1;
public static final int TYPE_SCONTO = 2;

@Override
public int getItemViewType(int position) {

    if (items.get(position) instanceof Article)
        return TYPE_PRODOTTO;
    else
        return TYPE_SCONTO;
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View rowView = LayoutInflater.from(parent.getContext()).inflate(viewType == TYPE_PRODOTTO ? R.layout.item_cart : R.layout.item_cart_sconto, parent, false);
    return new ViewHolder(rowView);
}

@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
    final ViewHolder viewHolder = (ViewHolder) holder;

    final Object object = items.get(position);

    if (object instanceof Article) {

        viewHolder.getBinding().setVariable(BR.article, object);
        viewHolder.getBinding().executePendingBindings();

        assert viewHolder.quantitySpinner != null;
        assert viewHolder.cartoneQuantity != null;
        assert viewHolder.cartoneValue != null;

        CartSpinnerAdapter adapter = (CartSpinnerAdapter) viewHolder.quantitySpinner.getAdapter();
        adapter.clear();
        adapter.setCount(((Article) object).getQuantityAvailable());
        adapter.notifyDataSetChanged();

        viewHolder.quantitySpinner.setSelection(((Article) object).getQuantity() - 1); //In teoria qui la quantità non deve mai essere zero

        viewHolder.cartoneQuantity.setVisibility(position % 2 == 1 ? View.GONE : View.VISIBLE); //Controllo da togliere in futuro
        viewHolder.cartoneValue.setVisibility(position % 2 == 1 ? View.GONE : View.VISIBLE); //Controllo da togliere in futuro
    }

    final PopupMenu popup = new PopupMenu(getContext(), viewHolder.deleteMenu);
    MenuInflater inflater = popup.getMenuInflater();
    inflater.inflate(R.menu.delete_menu, popup.getMenu());

    viewHolder.deleteMenu.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            popup.show();
        }
    });

    popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
        @Override
        public boolean onMenuItemClick(MenuItem item) {
            if (item.getItemId() == R.id.action_delete) {
                removeData(holder.getAdapterPosition());
                ((CartActivity) activity).checkIfEmpty();
            }

            return true;
        }
    });
}

public class ViewHolder extends RecyclerView.ViewHolder {

    @BindView(R.id.item)
    View item;
    @Nullable
    @BindView(R.id.cart_image)
    ImageView cartImage;
    @BindView(R.id.delete_menu)
    ImageView deleteMenu;
    @Nullable
    @BindView(R.id.product_cartone_quantity)
    TextView cartoneQuantity;
    @Nullable
    @BindView(R.id.product_cartone_value)
    TextView cartoneValue;
    @Nullable
    @BindView(R.id.quantity_spinner)
    AppCompatSpinner quantitySpinner;

    private ViewDataBinding binding;

    public ViewHolder(View itemView) {
        super(itemView);
        ButterKnife.bind(this, itemView);
        binding = DataBindingUtil.bind(itemView);
        if (quantitySpinner != null)
            quantitySpinner.setAdapter(new CartSpinnerAdapter(itemView.getContext(), R.layout.support_simple_spinner_dropdown_item));
    }

    public ViewDataBinding getBinding() {
        return binding;
    }
}
}

public class CartSpinnerAdapter extends ArrayAdapter<String> {

LayoutInflater inflater;

int count;

public CartSpinnerAdapter(Context context, int resource) {
    super(context, resource);

    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

public CartSpinnerAdapter(Context context, int resource, int count) {
    super(context, resource);

    this.count = count;
    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

public void setCount(int count) {
    this.count = count;
}

@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
    return getStandardView(position, parent, true);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    return getStandardView(position, parent, false);
}

@Override
public int getCount() {
    return count;
}

private View getStandardView(int position, ViewGroup parent, boolean dropdown) {
    View row = inflater.inflate(R.layout.support_simple_spinner_dropdown_item, parent, false);

    TextView title = (TextView) row.findViewById(android.R.id.text1);

    title.setText(String.valueOf(position + 1));

    if (dropdown)
        title.setMinWidth(Utils.dpToPx(getContext(), 64));
    else
        title.setAlpha(0.5f);

    return row;
}
}

CartSpinnerAdapter adapter = (CartSpinnerAdapter) viewHolder.quantitySpinner.getAdapter();
adapter.clear();
adapter.setCount(((Article) object).getQuantityAvailable());
adapter.notifyDataSetChanged();

这样，当我滚动

RecyclerView

时，我遇到了延迟

如果删除这些行，一切正常：

public class CartAdapter extends BaseAdapter<Object> {

public CartAdapter(AbstractBaseActivity activity) {
    super(activity);
}

public static final int TYPE_PRODOTTO = 1;
public static final int TYPE_SCONTO = 2;

@Override
public int getItemViewType(int position) {

    if (items.get(position) instanceof Article)
        return TYPE_PRODOTTO;
    else
        return TYPE_SCONTO;
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View rowView = LayoutInflater.from(parent.getContext()).inflate(viewType == TYPE_PRODOTTO ? R.layout.item_cart : R.layout.item_cart_sconto, parent, false);
    return new ViewHolder(rowView);
}

@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
    final ViewHolder viewHolder = (ViewHolder) holder;

    final Object object = items.get(position);

    if (object instanceof Article) {

        viewHolder.getBinding().setVariable(BR.article, object);
        viewHolder.getBinding().executePendingBindings();

        assert viewHolder.quantitySpinner != null;
        assert viewHolder.cartoneQuantity != null;
        assert viewHolder.cartoneValue != null;

        CartSpinnerAdapter adapter = (CartSpinnerAdapter) viewHolder.quantitySpinner.getAdapter();
        adapter.clear();
        adapter.setCount(((Article) object).getQuantityAvailable());
        adapter.notifyDataSetChanged();

        viewHolder.quantitySpinner.setSelection(((Article) object).getQuantity() - 1); //In teoria qui la quantità non deve mai essere zero

        viewHolder.cartoneQuantity.setVisibility(position % 2 == 1 ? View.GONE : View.VISIBLE); //Controllo da togliere in futuro
        viewHolder.cartoneValue.setVisibility(position % 2 == 1 ? View.GONE : View.VISIBLE); //Controllo da togliere in futuro
    }

    final PopupMenu popup = new PopupMenu(getContext(), viewHolder.deleteMenu);
    MenuInflater inflater = popup.getMenuInflater();
    inflater.inflate(R.menu.delete_menu, popup.getMenu());

    viewHolder.deleteMenu.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            popup.show();
        }
    });

    popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
        @Override
        public boolean onMenuItemClick(MenuItem item) {
            if (item.getItemId() == R.id.action_delete) {
                removeData(holder.getAdapterPosition());
                ((CartActivity) activity).checkIfEmpty();
            }

            return true;
        }
    });
}

public class ViewHolder extends RecyclerView.ViewHolder {

    @BindView(R.id.item)
    View item;
    @Nullable
    @BindView(R.id.cart_image)
    ImageView cartImage;
    @BindView(R.id.delete_menu)
    ImageView deleteMenu;
    @Nullable
    @BindView(R.id.product_cartone_quantity)
    TextView cartoneQuantity;
    @Nullable
    @BindView(R.id.product_cartone_value)
    TextView cartoneValue;
    @Nullable
    @BindView(R.id.quantity_spinner)
    AppCompatSpinner quantitySpinner;

    private ViewDataBinding binding;

    public ViewHolder(View itemView) {
        super(itemView);
        ButterKnife.bind(this, itemView);
        binding = DataBindingUtil.bind(itemView);
        if (quantitySpinner != null)
            quantitySpinner.setAdapter(new CartSpinnerAdapter(itemView.getContext(), R.layout.support_simple_spinner_dropdown_item));
    }

    public ViewDataBinding getBinding() {
        return binding;
    }
}
}

public class CartSpinnerAdapter extends ArrayAdapter<String> {

LayoutInflater inflater;

int count;

public CartSpinnerAdapter(Context context, int resource) {
    super(context, resource);

    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

public CartSpinnerAdapter(Context context, int resource, int count) {
    super(context, resource);

    this.count = count;
    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

public void setCount(int count) {
    this.count = count;
}

@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
    return getStandardView(position, parent, true);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    return getStandardView(position, parent, false);
}

@Override
public int getCount() {
    return count;
}

private View getStandardView(int position, ViewGroup parent, boolean dropdown) {
    View row = inflater.inflate(R.layout.support_simple_spinner_dropdown_item, parent, false);

    TextView title = (TextView) row.findViewById(android.R.id.text1);

    title.setText(String.valueOf(position + 1));

    if (dropdown)
        title.setMinWidth(Utils.dpToPx(getContext(), 64));
    else
        title.setAlpha(0.5f);

    return row;
}
}

CartSpinnerAdapter adapter = (CartSpinnerAdapter) viewHolder.quantitySpinner.getAdapter();
adapter.clear();
adapter.setCount(((Article) object).getQuantityAvailable());
adapter.notifyDataSetChanged();

因此，问题是如何处理

微调器的适配器，如何处理

提前感谢。
Short

为了提高绩效

从onBindViewHolder删除分配
重新使用布局更平坦的布局，而不是每次都得到一个新的布局

尽量减少BindViewHolder实施中的重复工作
微调器适配器也应循环使用视图

背景

当使用适配器进行滚动时，最重要的是要确保我们不分配新对象（或尽可能减少）

带有适配器的RecyclerView的全部目的是确保我们回收对象，从而使滚动过程中所需的工作量最小化

由于分配内存非常“昂贵”，为了提高滚动性能，首先要寻找的是在onBindViewHolder期间的分配。所有分配（如果有）都应在onCreateViewHolder中进行

一旦所有的分配都被清理干净，如果我们仍然落后，是时候进行一些微观改进了。这些包括提高代码质量、重用逻辑结果等

怎么办？

1） 从onBindViewHolder删除分配

在以下代码中：

final PopupMenu popup = new PopupMenu(getContext(), viewHolder.deleteMenu);
MenuInflater inflater = popup.getMenuInflater();
inflater.inflate(R.menu.delete_menu, popup.getMenu());

viewHolder.deleteMenu.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        popup.show();
    }
});

popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
    @Override
    public boolean onMenuItemClick(MenuItem item) {
        if (item.getItemId() == R.id.action_delete) {
            removeData(holder.getAdapterPosition());
            ((CartActivity) activity).checkIfEmpty();
        }

        return true;
    }
});

public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View rowView = LayoutInflater.from(parent.getContext()).inflate(viewType == TYPE_PRODOTTO ? R.layout.item_cart : R.layout.item_cart_sconto, parent, false);
    return new ViewHolder(rowView);
}

viewHolder.cartoneQuantity.setVisibility(position % 2 == 1 ? View.GONE : View.VISIBLE); //Controllo da togliere in futuro
viewHolder.cartoneValue.setVisibility(position % 2 == 1 ? View.GONE : View.VISIBLE); //Controllo da togliere in futuro

您目前有3个直接分配（新建）和一些间接分配（膨胀）。更改此代码，使所有分配都位于onCreateViewHolder中。例如：

在onCreateViewHolder中执行如下分配：

// Allocate Listener only ONCE per recycled view 
viewHolder.deleteMenu.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        // Get needed data from the view TAG, we will set it later
        final int itemPosition = (Integer)view.getTag();

        // Do work only when needed - when user clicked the button
        final PopupMenu popup = new PopupMenu(getContext(), viewHolder.deleteMenu);
        MenuInflater inflater = popup.getMenuInflater();
        inflater.inflate(R.menu.delete_menu, popup.getMenu());

        popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
            @Override
            public boolean onMenuItemClick(MenuItem item) {
                // Do logic using itemPosition etc
                return true;
            }
        });

        popup.show();
    }
});

在onBindViewHolder中按如下方式绑定相关数据：

viewHolder.deleteMenu.setTag(holder.getAdapterPosition());

2） 重新使用布局更平坦的布局，而不是每次都得到一个新的布局

在以下代码中：

final PopupMenu popup = new PopupMenu(getContext(), viewHolder.deleteMenu);
MenuInflater inflater = popup.getMenuInflater();
inflater.inflate(R.menu.delete_menu, popup.getMenu());

viewHolder.deleteMenu.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        popup.show();
    }
});

popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
    @Override
    public boolean onMenuItemClick(MenuItem item) {
        if (item.getItemId() == R.id.action_delete) {
            removeData(holder.getAdapterPosition());
            ((CartActivity) activity).checkIfEmpty();
        }

        return true;
    }
});

public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View rowView = LayoutInflater.from(parent.getContext()).inflate(viewType == TYPE_PRODOTTO ? R.layout.item_cart : R.layout.item_cart_sconto, parent, false);
    return new ViewHolder(rowView);
}

viewHolder.cartoneQuantity.setVisibility(position % 2 == 1 ? View.GONE : View.VISIBLE); //Controllo da togliere in futuro
viewHolder.cartoneValue.setVisibility(position % 2 == 1 ? View.GONE : View.VISIBLE); //Controllo da togliere in futuro

你每次都会得到一个新的工作机会。这是一种浪费。最好在适配器构造函数中获取一个，并将其另存为成员

3） 尽量减少BindViewHolder实施中的重复工作

例如，在以下代码中：

final PopupMenu popup = new PopupMenu(getContext(), viewHolder.deleteMenu);
MenuInflater inflater = popup.getMenuInflater();
inflater.inflate(R.menu.delete_menu, popup.getMenu());

viewHolder.deleteMenu.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        popup.show();
    }
});

popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
    @Override
    public boolean onMenuItemClick(MenuItem item) {
        if (item.getItemId() == R.id.action_delete) {
            removeData(holder.getAdapterPosition());
            ((CartActivity) activity).checkIfEmpty();
        }

        return true;
    }
});

public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View rowView = LayoutInflater.from(parent.getContext()).inflate(viewType == TYPE_PRODOTTO ? R.layout.item_cart : R.layout.item_cart_sconto, parent, false);
    return new ViewHolder(rowView);
}

viewHolder.cartoneQuantity.setVisibility(position % 2 == 1 ? View.GONE : View.VISIBLE); //Controllo da togliere in futuro
viewHolder.cartoneValue.setVisibility(position % 2 == 1 ? View.GONE : View.VISIBLE); //Controllo da togliere in futuro

您正在计算相同的逻辑两次。最好只计算一次并重用结果：

int cartoneVisibility = position % 2 == 1 ? View.GONE : View.VISIBLE;
viewHolder.cartoneQuantity.setVisibility(cartoneVisibility); //Controllo da togliere in futuro
viewHolder.cartoneValue.setVisibility(cartoneVisibility); //Controllo da togliere in futuro

4） 微调器适配器也应循环使用视图

在
CartSpinnerAdapter.getView（）
中，您也在分配内存。它发生了（每次*列表项*计数）-这是大量的分配。请改用convertView。查看本教程
您好，感谢您的回复。自从我将适配器逻辑添加到微调器之后，我遇到了滞后问题，即使有了这些改进，滞后问题也无法解决。因此，我真正的问题是，如何在recyclerview适配器中使用微调器适配器？同时，将建议应用于CartSpinnerAdapter。由于未回收视图，因此未正确使用适配器。使用convertView。延迟是由以下行引起的：“CartSpinnerAdapter=（CartSpinnerAdapter）viewHolder.quantitySpinner.getAdapter（）；adapter.clear（）；adapter.setCount（（（文章）对象）。getQuantityAvailable（））；adapter.notifyDataSetChanged（）；”如我所说，在CartSpinnerAdapter中。getView您正在分配内存。每次*列表项*计数时都会发生这种情况-这是一个很大的分配。实际上，您需要0个分配。请改用convertView。看看这个教程@RRR，在本例中，“绑定”是setCount函数。在其他情况下，我们可能有其他绑定。无论如何，最重要的是要记住，我们不应该在UI布局期间快速调用的函数中分配内存。找到分配，把它们拿出来，你就是黄金：）