android - 在 RecyclerView 中更新 ProgressBar

Question

我有一个 RecyclerView。其中，项目具有标准布局 - 一个 TextView 和一个 ProgressBar。项目在运行时添加到 recyclerview。每当添加一个 Item 时，都会启动一个 AsyncTask 来更新 ProgressBar。AsynTask 持有对来自 RecyclerView Adapter 的 ProgressBar 对象的引用。当回收站 View 中的项目过多时会出现此问题。

我知道 RecyclerView 会回收任何旧 View ，因此至少要为进度条找到解决方法。

实现它的理想方式是什么？

以下是适配器的摘录

public class RecViewAdapter extends
        RecyclerView.Adapter<RecViewAdapter.ViewHolder> {
    Context mContext;
    List<String> mRunns;
    static ExecutorService mExec;
    static HashSet<Integer> mProcessed = new HashSet<>();

    public RecViewAdapter(Context context, List<String> runns) {
        mContext = context;
        mRunns = runns;
        mExec = Executors.newFixedThreadPool(1);
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
        View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.runnabel_item, viewGroup,
                false);
        ViewHolder vh = new ViewHolder(v);
        return vh;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.runnName.setText(mRunns.get(position));
        if (!mProcessed.contains(position)) {
            new ProgressTask(holder.pBar, position).executeOnExecutor(mExec, null);
            mProcessed.add(position);
        }
    }

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

    public static class ViewHolder extends RecyclerView.ViewHolder {
        TextView runnName;
        ProgressBar pBar;

        public ViewHolder(View view) {
            super(view);
            runnName = (TextView) view.findViewById(R.id.textView);
            pBar = (ProgressBar) view.findViewById(R.id.progressBar);
            pBar.setIndeterminate(false);
            pBar.setMax(100);
            pBar.setProgress(0);

        }
    }
}

此外，我正在使用 notifydatasetchanged 将项目添加到 RecyclerView。

Answer 1

您可以简单地使用回收 View 的“findViewHolderForAdapterPosition”方法，您将从中获得一个 viewHolder 对象，然后将该 viewHolder 类型转换为您的适配器 View ，这样您就可以直接访问您的 View ，(在本例中我们访问 progressBar)

以下是kotlin的示例代码

 /**
     * update progress bar in recycler view
     * get viewHolder from position and progress bar from that viewHolder
     *  we are rapidly updating progressbar so we did't use notify method as it always update whole row instead of only progress bar
     *  @param position : position of list cell
     *  @param progress : new progress value
     */
    private fun updateDownloadProgressBar(position :Int, progress:Int)
    {
        val viewHolder = recyclerViewDownload.findViewHolderForAdapterPosition(position)
        (viewHolder as ViewHolderDownload).progressBarDownload.progress=progress
    }