什么是RecyclerView适配器的生命周期? [英] What is lifecycle for RecyclerView adapter?

问题描述

我正在从适配器中的演示者请求图像:

I'm requesting images from presenter in adapter:

  @Override
  public void onBindViewHolder(SiteAdapter.ViewHolder holder, int position)
  {
    Site site = sites.get(position);
    holder.siteName.setText(site.getName());
    requestHolderLogo(holder, site.getLinks().getLogoUrl());
  }

  private void requestHolderLogo(final ViewHolder holder, final String logoUrl)
  {
    compositeSubscription.add(
      presenter.bitmap(logoUrl)
        .subscribe(
          bitmap -> {
            holder.siteLogo.setImageBitmap(bitmap);
            holder.siteLogo.setVisibility(View.VISIBLE);
          },
          error -> {
            holder.siteName.setVisibility(View.VISIBLE);
          })
    );
  }

重新使用ViewHolder时，我应该退订.很简单.

I should unsubscribe when ViewHolder is re-used. It is easy.

但是，当视图被破坏时，如何停止所有订阅呢?我也应该取消演示者引用，以避免内存泄漏

But how stop all subscription when view is destroyed? I should also probably nullify presenter reference to avoid memory leak

推荐答案

我认为最好的方法是:

1. 在SiteAdapter.ViewHolder
中保留subscription引用
2. unsubscribe onBindViewHolder中的subscription对象(重用ViewHolder时会调用它)
3. 将CompositeSubscription对象保留在adapter
中
4. 使用Adapter的onDetachedFromRecyclerView方法将unsubscribe compositeSubscription

1. Keep a subscription reference in the SiteAdapter.ViewHolder
2. unsubscribe the subscription object in onBindViewHolder (it's called when the ViewHolder is reused)
3. Keep the CompositeSubscription object in your adapter
4. Use the onDetachedFromRecyclerView method of your Adapter to unsubscribe the compositeSubscription

像这样:

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

    private CompositeSubscription compositeSubscription = new CompositeSubscription();

    // other needed SiteAdapter methods

    @Override
    public void onBindViewHolder(SiteAdapter.ViewHolder holder, int position) {
        if (holder.subscription != null && !holder.subscription.isUnsubscribed()) {
            compositeSubscription.remove(holder.subscription);
            // this will unsubscribe the subscription as well
        }
        Site site = sites.get(position);
        holder.siteName.setText(site.getName());
        requestHolderLogo(holder, site.getLinks().getLogoUrl());
    }

    private void requestHolderLogo(final SiteAdapter.ViewHolder holder, final String logoUrl) {
        holder.subscription = presenter.bitmap(logoUrl)
                .subscribe(
                        bitmap -> {
                            holder.siteLogo.setImageBitmap(bitmap);
                            holder.siteLogo.setVisibility(View.VISIBLE);
                        },
                        error -> {
                            holder.siteName.setVisibility(View.VISIBLE);
                        });
        compositeSubscription.add(holder.subscription);
    }

    @Override
    public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
        compositeSubscription.unsubscribe();
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {

        public Subscription subscription;

        // some holder-related stuff

        public ViewHolder(View itemView) {
            super(itemView);
            // init holder
        }
    }
}

这篇关于什么是RecyclerView适配器的生命周期?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！