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在recyclerview中为特定列表项添加处理程序

recycler-adapter android-recyclerview android

Shubham Agrawal · 技术社区 · 7 年前

我只想在每个列表项加载程序和图像中添加一个延迟,并在recycler视图中完成进度后显示图像,添加3秒的延迟。

这是我的 适配器

@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View layoutView;
    switch (viewType) {
        case USER_HEADER:
            layoutView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_user_header, parent, false);
            return new HeaderViewHolder(layoutView);
        default:
            layoutView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_user_info, parent, false);
            return new AppListViewHolder(layoutView, onRecyclerItemClick);

    }
}


@Override
public int getItemViewType(int position) {
    if (position == 0) {
        return USER_HEADER;
    }
    return USER_ITEM;
}

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

    if (holder.getItemViewType() == USER_HEADER) return;

    final AppListViewModel appListViewModel = appListViewModels.get(position - 1);
    final AppListViewHolder appListViewHolder = (AppListViewHolder) holder;
    if (!appListViewModel.isAppInstalled()) {
        appListViewHolder.textAppLink.setText(appListViewModel.getAppLink());
    } else {
        appListViewHolder.textAppLink.setText("");
    }
    appListViewHolder.textAppName.setText(appListViewModel.getAppName());
    appListViewHolder.itemView.setTag(appListViewModel);

    // TODO I want to add this progressbar and image after every 3 sec. Just like checking the installation after every 3 sec.
    appListViewHolder.progressBar.setVisibility(View.VISIBLE);
    appListViewHolder.imageStatus.setImageResource(appListViewModel.isAppInstalled() ? R.drawable.ic_check_green : R.drawable.cancel);
    setAdapterData(holder);
    loaderStatusListner.isLoadingComplete(true);

}

private void setAdapterData(RecyclerView.ViewHolder viewHolder){
    this.viewHolder = viewHolder;
}
public RecyclerView.ViewHolder getAdapterData(){
    return viewHolder;
}

@Override
public int getItemCount() {
    return 1 + appListViewModels.size();
}


private static class HeaderViewHolder extends RecyclerView.ViewHolder {

    HeaderViewHolder(View itemView) {
        super(itemView);
    }
}

static class AppListViewHolder extends RecyclerView.ViewHolder {
    @BindView(R.id.image_app_status)
    public ImageView imageStatus;
    @BindView(R.id.text_app_name)
    TextView textAppName;
    @BindView(R.id.text_app_link)
    TextView textAppLink;
    @BindView(R.id.progress_bar)
    public ProgressBar progressBar;


    AppListViewHolder(View view, final OnRecyclerItemClick onRecyclerItemClick) {
        super(view);
        ButterKnife.bind(this, view);

        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                AppListViewModel commonTicketViewModel = (AppListViewModel) v.getTag();
                onRecyclerItemClick.onItemClick(v, getAdapterPosition(), commonTicketViewModel);
            }
        });

    }
}

加载器应继续移动,在3秒延迟和图像更改后,其可见性将一个接一个地变为不可见。有关更多说明,请参见图

2 回复 | 直到 7 年前

aminography 7 年前

因为回收程序 RecyclerView 您不能仅在中使用处理程序来处理它 ViewHolder . 在本例中,通过滚动列表 itemView 已更改并指向新视图,通过完成处理程序的延迟,它可能会更新错误的视图。因此,您应该将更新时间作为字段保存在 AppListViewModel System.currentTimeInMillis() + (i + 1) * 3000 作为每行的更新时间。然后在view holder类中(您在其中编写 TODO )将当前时间与viewModel实例中的行的更新时间进行比较。如果时间已过,则更新视图。最后,在你的 Fragment Activity )它初始化了 Adapter ,试着打电话 adapter.notifyDatasetChange()

您可以使用以下类保持每秒触发一次:

private class SchedulerHandler extends Handler {

    private static final long SCHEDULE_TIME = 1000;
    private static final int MSG_START = 1;

    private SchedulerHandler(Looper looper) {
        super(looper);
    }

    @Override
    public void handleMessage(Message msg) {
        switch (msg.what) {
            case MSG_START:
                // call adapter.notifyDatasetChanged()
                sendEmptyMessageDelayed(MSG_START, SCHEDULE_TIME);
                break;
            default:
                throw new IllegalArgumentException("Unknown what=" + msg.what);
        }
    }

    void startScheduling() {
        sendEmptyMessage(SchedulerHandler.MSG_START);
    }

    void stopScheduling() {
        removeMessages(SchedulerHandler.MSG_START);
    }

}

用法:

SchedulerHandler schedulerHandler = new SchedulerHandler();
schedulerHandler.startScheduling();

在更新结束时:

schedulerHandler.stopScheduling();

Shubham Agrawal 7 年前

handler 我的国家 progressabar image 在我的 ViewModel

Message message = new Message();
message.arg1 = 0;
message.what = 0;
handler.sendMessageDelayed(message, 2000);

然后添加处理程序来处理该消息:

private Handler handler = new Handler(Looper.getMainLooper()) {
    @Override
    public void handleMessage(Message msg) {
        super.handleMessage(msg);
        int position = msg.arg1;
        appListViewModels.get(position).setProgressState("INACTIVE");
        appListViewModels.get(position).setImageState("ACTIVE");
        userListAdapter.notifyItemChanged(position + 1);
        if (position < userListAdapter.getItemCount() - 2) {
            appListViewModels.get(position + 1).setProgressState("ACTIVE");
            userListAdapter.notifyItemChanged(position + 2);
        }

        if (position < userListAdapter.getItemCount() - 2) {
            Message message = new Message();
            message.arg1 = position + 1;
            message.what = 0;
            handler.sendMessageDelayed(message, 2000);
        } else {
            if (totalActivatedApps == 5) {
                buttonContinue.setEnabled(true);

            } else {
                buttonContinue.setEnabled(false);
            }
        }

    }
};