Question

我现在正在处理的Android应用程序的recyclerview适配器的代码如下：

 @Override
public void onBindViewHolder(final FeedViewHolder contactViewHolder, final int i) {

    final FeedInfo ci = feedInfoList.get(i);

    //Set the text of the feed with your data
    contactViewHolder.feedText.setText(ci.getFeed());
    contactViewHolder.surNameText.setText(ci.getSurName());
    contactViewHolder.nameText.setText(ci.getFirstName());
    contactViewHolder.feedDate.setText(ci.getDate());
    contactViewHolder.numberOfGoingText.setText(ci.getNumber_of_going());
    contactViewHolder.numberOfInterestedText.setText(ci.getNumber_of_interested());

    //seteaza fotografia de profil in postare
    new ProfilePictureDownloadImage(contactViewHolder.profilePicture).execute(ci.getProfileImageURL());

    ImageButton interestedButton = contactViewHolder.interestedButton;
    interestedButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            int position = i;
            FeedInfo fi = feedInfoList.get(position);
            int displayedNumberOfInterested = Integer.parseInt(ci.getNumber_of_interested()) + 1;
            contactViewHolder.numberOfInterestedText.setText(Integer.toString(displayedNumberOfInterested));
            System.out.println("emilutzy interested from within" + fi.getPostID());
            contactViewHolder.surNameText.setText("kk");
        }
    });
}

问题是点击监听器。理论上，我按下的按钮应该增加它旁边的数字。但是，由于我必须将onBindViewHolder的参数声明为final，只有第一次点击有效，其余的点击不会更改数字的值。我是Android新手，您能帮我找一个更好的解决方案吗？

Answer 1

我不确定对象FeedInfo的外观如何，但你也可以使用一个名为increaseNumberOfInterested()的方法，它会将Number_of_interested的值增加一，并且会在recyclerview回收单元格时，该对象会持续存在。它有点像下面

 @Override
public void onBindViewHolder(final FeedViewHolder contactViewHolder, final int i) {

final FeedInfo ci = feedInfoList.get(i);

//Set the text of the feed with your data
contactViewHolder.numberOfInterestedText.setText(ci.getNumber_of_interested());


contactViewHolder.interestedButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {

        //Increase the number of interested in the object, so it can be persisted when cell is reclycled
        ci.setNumberOfInterested(ci.getNumber_of_interested()) + 1);

        //Get new value and display 
  contactViewHolder.numberOfInterestedText.setText(Integer.toString(ci.getNumber_of_interested()));
}

Answer 2

有一个名为getAdapterPosition()的好方法，您可以在RecyclerView的{{1}}中使用。

不是在ViewHolder中设置点击监听器，而是在onBindViewHolder的构造函数中设置它，如下所示：

ViewHolder

请勿将您的位置设置为public class FeedViewHolder extends RecyclerView.ViewHolder { private TextView feedText; private TextView surNameText; private Button interestedButton; // ... the rest of your viewholder elements public FeedViewHolder(View itemView) { super(itemView); feedtext = itemView.findViewById(R.id.feedtext); // ... find your other views interestedButton.setOnClickListener(new View.OnClickListener() { final FeedInfo fi = feedInfoList.get(getAdapterPosition()); int numInterested = Integer.parseInt(ci.getNumber_of_interested()) + 1; // setting the views here might work, // but you will find that they reset themselves // after you scroll up and down (views get recycled). // find a way to update feedInfoList, // I like to use EventBus to send an event to the // host activity/fragment like so: EventBus.getDefault().post( new UpdateFeedInfoListEvent(getAdapterPosition(), numInterested)); // in your host activity/fragment, // update the list and call // notifyDatasetChanged/notifyDataUpdated() //on this RecyclerView adapter accordingly }); } }至最终版（Android Studio会警告您原因）。

单击OnBindViewHolder中的侦听器

2 个答案: