单击 OnBindViewHolder 中的侦听器

Question

我现在正在开发的 android 应用的 recyclerview 适配器有以下代码：

 @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");
        }
    });
}

问题出在点击监听器上。理论上，我按下的按钮应该会增加旁边的数字。但是，由于我必须将 onBindViewHolder 的参数声明为最终参数，因此只有第一次点击有效，其余点击不会更改数字的值。我是 Android 的新手，请问您能帮我找到更好的解决方案吗？

Answer 1

我不确定对象 FeedInfo 的样子，但您也可以使用一种方法，例如 increaseNumberOfInterested()，它将 Number_of_interested 的值增加一，并且当 recyclerview 回收单元格时保留在对象中。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 ViewHolder 中使用它。

不要在 onBindViewHolder 中设置点击侦听器，而是像这样在 ViewHolder 的构造函数中设置它：

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
        });
    }
}

不要将您在 onBindViewHolder 中的位置设置为最终位置（Android Studio 会警告您原因）。

单击 OnBindViewHolder 中的侦听器

Click listener inside OnBindViewHolder

java

android

clicklistener