RecyclerView中的选定项目在滚动时发生更改

小编典典

RecyclerView中的选定项目在滚动时发生更改

java

我有一个RecyclerView，每个元素代表一个事件。我想让用户通过单击选择事件。选择后，事件和报告按钮将变为彩色：

进行点击之前的用户界面：点击此处。

用户界面执行单击后：单击此处。

这非常简单，并且据称有效。我OnClickListener为每个ViewHolder负责为项目着色的对象设置了一个，并在触发时触发了名为的拥有活动中的另一个事件，该事件onOccurrenceSelected负责更改按钮的状态。

但是，滚动浏览RecyclerView的项目时，其他不相关的项目会像OnClickListener被触发一样被着色（尽管不是），而向后滚动时，选定的事件则被着色为未选中。发生这种情况时，不会触发应该为项目着色的唯一事件。

对这种行为有任何解释吗？谢谢！

编辑：这是适配器的一些相关代码：

private List<Occurrence> mDataSet;
private Activity activity;

public <OccurrencesActivity extends OnOccurrenceSelectedListener> OccurrencesAdapter(OccurrencesActivity occurrencesActivity, List<Occurrence> occurrences) {
    this.activity = (android.app.Activity) occurrencesActivity;
    mDataSet = occurrences;
}

@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
    Occurrence instance = mDataSet.get(position);
    ...
    setOnClickListener(holder, instance);
    }

private void setOnClickListener(final ViewHolder holder, final Occurrence occurrence) {
    holder.itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (!occurrence.isSelected()) {
                holder.itemView.setBackgroundColor(App.getContext().getResources().getColor(R.color.turquoise));
                holder.titleTextView.setTextColor(App.getContext().getResources().getColor(R.color.white));
                holder.statusTextView.setTextColor(App.getContext().getResources().getColor(R.color.white));
                holder.dateTextView.setTextColor(App.getContext().getResources().getColor(R.color.white));
                holder.timeTextView.setTextColor(App.getContext().getResources().getColor(R.color.white));
            } else {
                holder.itemView.setBackgroundColor(App.getContext().getResources().getColor(R.color.white));
                holder.titleTextView.setTextColor(App.getContext().getResources().getColor(R.color.turquoise));
                holder.statusTextView.setTextColor(App.getContext().getResources().getColor(R.color.grey));
                holder.dateTextView.setTextColor(App.getContext().getResources().getColor(R.color.grey));
                holder.timeTextView.setTextColor(App.getContext().getResources().getColor(R.color.grey));
            }
            occurrence.setSelected(!occurrence.isSelected());

            ((OnOccurrenceSelectedListener)activity).onOccurrenceSelected(mDataSet);
        }
    });
}

阅读 282

2020-11-30

共1个答案

小编典典

Recyclerview总是在滚动时重用视图，因此您必须将选定的位置存储到临时arraylist中，然后将条件检查保持在onBindViewHolder中，以确保该特定位置是否已经存在于arraylist中？我更新了你的衣服。在评论中找到以下变化

    private List<Occurrence> mDataSet;
private Activity activity;

//Added here temporary ArrayList
private ArrayList<String> mSelectedPosition = new ArrayList<String>;

public <OccurrencesActivity extends OnOccurrenceSelectedListener> OccurrencesAdapter(OccurrencesActivity occurrencesActivity, List<Occurrence> occurrences) {
    this.activity = (android.app.Activity) occurrencesActivity;
    mDataSet = occurrences;
}

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


    //Set ViewTag
    holder.itemView.setTag(position);

    //Check everyposition during view binding process
    if(mSelectedPosition.contains(String.valueOf(position))){

     holder.itemView.setBackgroundColor(App.getContext().getResources().getColor(R.color.white));
                holder.titleTextView.setTextColor(App.getContext().getResources().getColor(R.color.turquoise));
                holder.statusTextView.setTextColor(App.getContext().getResources().getColor(R.color.grey));
                holder.dateTextView.setTextColor(App.getContext().getResources().getColor(R.color.grey));
                holder.timeTextView.setTextColor(App.getContext().getResources().getColor(R.color.grey));


     }else{
    holder.itemView.setBackgroundColor(App.getContext().getResources().getColor(R.color.white));
                    holder.titleTextView.setTextColor(App.getContext().getResources().getColor(R.color.turquoise));
                    holder.statusTextView.setTextColor(App.getContext().getResources().getColor(R.color.grey));
                    holder.dateTextView.setTextColor(App.getContext().getResources().getColor(R.color.grey));
                    holder.timeTextView.setTextColor(App.getContext().getResources().getColor(R.color.grey));

      }

    Occurrence instance = mDataSet.get(position);
    ...
    setOnClickListener(holder, instance);
    }

private void setOnClickListener(final ViewHolder holder, final Occurrence occurrence) {
    holder.itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

       // Get Position
         int position = (int) view.getTag();

            //Remove SelectedPosition if Already there
              if(mSelectedPosition.contains(position))
                  mSelectedPosition.remove(String.valueOf(position));
               else
                  mSelectedPosition.add(String.valueOf(position));

                notifyDataSetChanged();

               //Not sure about this lines 
                occurrence.setSelected(!occurrence.isSelected());

                ((OnOccurrenceSelectedListener)activity).onOccurrenceSelected(mDataSet);
            }
        });
    }

2020-11-30