在 RecyclerView 中更改单个可绘制对象的颜色将更改所有可绘制对象

Question

我只是尝试根据一个值更改行内可绘制对象的颜色，但适配器更改了所有可绘制对象而不是一个可绘制对象。

这是我的适配器：

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

    DataBaseHelper dataBase;

    private LayoutInflater inflater;
    List<ChoosedSubject> data = Collections.emptyList();
    Context context;
    OnItemClickListener itemClickListener;

    public ReportAdapter(Context context, List<ChoosedSubject> data, OnItemClickListener itemClickListener) {
        inflater = LayoutInflater.from(context);
        this.data = data;
        this.context = context;
        this.itemClickListener = itemClickListener;
    }

    @Override
    public ReportViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.report_cell, parent, false);
        ReportViewHolder holder = new ReportViewHolder(view);

        dataBase = new DataBaseHelper(context);

        return holder;
    }

    //Set Data inside RecyclerView
    @Override
    public void onBindViewHolder(ReportViewHolder holder, int position) {
        ChoosedSubject current = data.get(position);
        Grades grades = new Grades(context);

        Resources resources = context.getResources();
        int iconColor;
        Drawable icon;

        icon = ContextCompat.getDrawable(context, dataBase.getSpecificChoosedSubjectAppendingToName(current.getName()).get(0).getChoosedIcon());

        if (dataBase.getSpecificChoosedSubjectAppendingToName(current.getName()).get(0).getChoosedIcon() != R.drawable.subject_default) {
            iconColor = resources.getColor(dataBase.getSpecificChoosedSubjectAppendingToName(current.getName()).get(0).getChoosedColor());
            icon.setColorFilter(iconColor, PorterDuff.Mode.SRC_IN);
            holder.icon.setBackground(icon);
        } else {
            holder.icon.setImageResource(R.drawable.subject_default);
        }

        holder.subject.setText(current.getName().toString());

        NumberFormat formatter = NumberFormat.getNumberInstance();
        formatter.setMinimumFractionDigits(0);
        formatter.setMaximumFractionDigits(0);
        String output = formatter.format(dataBase.getSpecificChoosedSubjectAppendingToName(current.getName()).get(0).getAverage());

        int formattedValue = Integer.valueOf(output);


        //CHANGING COLOR DEPENDING ON VALUE
        int boxColor = 0;
        Drawable box = ContextCompat.getDrawable(context, R.drawable.markbox);
        Drawable boxBorder = ContextCompat.getDrawable(context, R.drawable.markbox_border);

        if (formattedValue >= 10) {
            boxColor = resources.getColor(R.color.positive);
        } else if (formattedValue >= 4 && formattedValue <= 9) {
            boxColor = resources.getColor(R.color.neutral);
        } else if (formattedValue < 4) {
            boxColor = resources.getColor(R.color.negative);

        }

        box.setAlpha(204);
        box.setColorFilter(boxColor, PorterDuff.Mode.SRC_IN);
        boxBorder.setColorFilter(boxColor, PorterDuff.Mode.SRC_IN);

        holder.markbox.setImageDrawable(box);
        holder.markboxBorder.setImageDrawable(boxBorder);


        holder.average.setText(output);
        holder.average.setTypeface(EasyFonts.robotoBlack(context));
    }

    @Override
    public int getItemCount() {
        return data.size();
    }


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

        TextView subject;
        ImageView icon;
        ImageView markbox;
        ImageView markboxBorder;
        TextView average;

        public ReportViewHolder(View itemView) {
            super(itemView);
            subject = (TextView) itemView.findViewById(R.id.report_subject);
            icon = (ImageView) itemView.findViewById(R.id.report_icon);
            markbox = (ImageView) itemView.findViewById(R.id.report_markbox);
            markboxBorder = (ImageView) itemView.findViewById(R.id.report_markbox_border);
            average = (TextView) itemView.findViewById(R.id.report_average);

            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {
            itemClickListener.onItemClick(v, this.getAdapterPosition());
        }

    }

}

有人知道该怎么做吗？谢谢你的帮助！！！

Answer 1

这是一种缓存。来自 Android docs:

if you instantiate two Drawable objects from the same image resource, then change a property (such as the alpha) for one of the Drawables, then it will also affect the other. So when dealing with multiple instances of an image resource, instead of directly transforming the Drawable, you should perform a tween animation.

Drawable.mutate() 创建后应该可以解决问题。

A mutable drawable is guaranteed to not share its state with any other drawable. This is especially useful when you need to modify properties of drawables loaded from resources. By default, all drawables instances loaded from the same resource share a common state; if you modify the state of one instance, all the other instances will receive the same modification.

像这样：

Drawable box = ContextCompat.getDrawable(context, R.drawable.markbox).mutate();
Drawable boxBorder = ContextCompat.getDrawable(context, R.drawable.markbox_border).mutate();

Answer 2

感谢 Sergey 指导我找到了解决方案。我分享我在 onBindViewHolder 方法中所做的事情。

final Drawable drawable = ContextCompat.getDrawable(mContext, R.drawable.ic_icon).mutate();

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
    holder.image.setBackground(drawable);
} else {
    holder.image.setBackgroundDrawable(drawable);
}

Answer 3

TL;DR. 如果您担心性能并且仍然想要一些缓存，请使用 TintedIconCache - 单个 class 您可以 grab from this gist.

TintedIconCache cache = TintedIconCache.getInstance();
Drawable coloredIcon = cache.fetchTintedIcon(context, R.drawable.ic, R.color.color));

TintedIconCache 是如何工作的？

它管理一个缓存，以便只有一个具有独特颜色的可绘制对象实例保存在内存中。它应该快速，并且内存高效。

// Get an instance
TintedIconCache cache = TintedIconCache.getInstance();

// Will be fetched from the resources
Drawable backIcon = cache.fetchTintedIcon(context, R.drawable.icon, R.color.black));

// Will be fetched from the resources as well
Drawable bleuIcon = cache.fetchTintedIcon(context, R.drawable.icon, R.color.bleu));
   
// Will be fetched from the cache!!!
Drawable backIconTwo = cache.fetchTintedIcon(context, R.drawable.icon, R.color.back));

查看 this answer 了解更多详情。

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考虑查看 gist 以了解它是如何工作的。