展开时折叠所有其他 Recyclerview 项目答案

【问题标题】：Collapsing all other Recyclerview items when one is expanded展开时折叠所有其他 Recyclerview 项目
【发布时间】：2017-06-27 16:15:26
【问题描述】：

我有一个设置良好的可扩展回收器视图。单击任何项目时，它会展开以显示更多详细信息。但我想在这里改变一下。单击一项以展开时，应折叠所有其他项。这是我的适配器代码：

public class DataAdapter extends RecyclerView.Adapter<DataAdapter.ViewHolder> {
    private ArrayList<ListItem> android_versions;
    private List<ListItem> listItems;
    private LayoutInflater layoutInflater;
    private Animation animationUp, animationDown;
    private Context context;
    private final int COUNTDOWN_RUNNING_TIME = 500;
    int i =0;

    public DataAdapter(Context context, java.util.List<ListItem> android_versions,
                       Animation animationUp, Animation animationDown) {
        this.context = context;
        this.listItems = android_versions;
        this.animationDown = animationDown;
        this.animationUp = animationUp;
    }

    @Override
    public DataAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.row_layout, viewGroup, false);
        return new ViewHolder(view);
    }

    public String getRandomColor(int a){
        String colors[] = {"#ef5350","#f44336","#ef5350"};
        return colors[a];
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, int i) {
        ListItem listItem = listItems.get(i);
        if (i%2==2)
            holder.itemView.setBackgroundColor(Color.parseColor(getRandomColor(0)));
        else if (i%2==1)
            holder.itemView.setBackgroundColor(Color.parseColor(getRandomColor(1)));
        else if (i%2==0)
            holder.itemView.setBackgroundColor(Color.parseColor(getRandomColor(2)));

        holder.tv_android.setText(listItem.getSubName());
        holder.contentLayout.setText(listItem.getContent());
        holder.expandit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if (holder.contentLayout.isShown()) {
                    holder.contentLayout.startAnimation(animationUp);
                    CountDownTimer countDownTimerStatic = new CountDownTimer(COUNTDOWN_RUNNING_TIME, 16) {
                        @Override
                        public void onTick(long millisUntilFinished) {
                        }

                        @Override
                        public void onFinish() {
                            holder.contentLayout.setVisibility(View.GONE);
                        }
                    };
                    countDownTimerStatic.start();
                } else {
                    holder.contentLayout.setVisibility(View.VISIBLE);
                    holder.contentLayout.startAnimation(animationDown);
                }
            }
        });
    }
    @Override
    public int getItemCount() {
        return listItems.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder{
        TextView tv_android;
        private TextView contentLayout;
        RelativeLayout expandit;
        public ViewHolder(View view) {
            super(view);
            tv_android = (TextView)view.findViewById(R.id.tv_android);
            contentLayout = (TextView) view.findViewById(R.id.content);
            expandit = (RelativeLayout)view.findViewById(R.id.expandit);
        }
    }
}

我认为不可能按位置更改 viewHolder 的内容。那么如何按位置隐藏所有其他项目的内容。我认为不需要其他代码，所以我没有包含它。

编辑：根据 Ashish 的建议编写代码：

  private void changeStateOfItemsInLayout(ListItem listItem) {
        for (int i = 0; i < listItems.size(); i++) {
            if (listItems.get(i) == listItem)
                listItem.setShouldBeExpanded(true);
            else
                listItem.setShouldBeExpanded(false);
        }
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, int i) {
        ListItem listItem = listItems.get(i);
        if (i%2==2)
            holder.itemView.setBackgroundColor(Color.parseColor(getRandomColor(0)));
        else if (i%2==1)
            holder.itemView.setBackgroundColor(Color.parseColor(getRandomColor(1)));
        else if (i%2==0)
            holder.itemView.setBackgroundColor(Color.parseColor(getRandomColor(2)));

        holder.tv_android.setText(listItem.getSubName());
        holder.contentLayout.setText(listItem.getContent());
        if(listItem.getShouldBeExpanded()){
            holder.contentLayout.setVisibility(View.VISIBLE);
            holder.contentLayout.startAnimation(animationDown);
        }else{
            holder.contentLayout.startAnimation(animationUp);
            CountDownTimer countDownTimerStatic = new CountDownTimer(COUNTDOWN_RUNNING_TIME, 16) {
                @Override
                public void onTick(long millisUntilFinished) {
                }

                @Override
                public void onFinish() {
                    holder.contentLayout.setVisibility(View.GONE);
                }
            };
            countDownTimerStatic.start();
        }

        holder.expandit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (holder.contentLayout.isShown()) {
                    holder.contentLayout.startAnimation(animationUp);
                    CountDownTimer countDownTimerStatic = new CountDownTimer(COUNTDOWN_RUNNING_TIME, 16) {
                        @Override
                        public void onTick(long millisUntilFinished) {
                        }

                        @Override
                        public void onFinish() {
                            holder.contentLayout.setVisibility(View.GONE);
                        }
                    };
                    countDownTimerStatic.start();
                } else {
                    holder.contentLayout.setVisibility(View.VISIBLE);
                    holder.contentLayout.startAnimation(animationDown);
                }
                listItems.get(holder.getLayoutPosition()).setShouldBeExpanded(true);
                changeStateOfItemsInLayout(listItems.get(holder.getLayoutPosition()));
                notifyDataSetChanged();
            }
        });
    }

虽然在onClick中，我还是有展开/折叠布局的代码，即使我把它去掉也不起作用。

如果需要，这是我的模态类：

public class ListItem {

    private String subName;
    private String content;
    private String param;
    private Boolean shouldBeExpanded=false;

    public Boolean getShouldBeExpanded() {
        return shouldBeExpanded;
    }

    public void setShouldBeExpanded(Boolean shouldBeExpanded) {
        this.shouldBeExpanded = shouldBeExpanded;
    }

    public ListItem(String subName, String content) {
        this.subName = subName;
        this.content = content;
        this.param = "Nothing";
    }

    public String getParam() {
        return param;
    }

    public ListItem(String subName, String content, String param) {

        this.subName = subName;
        this.content = content;
        this.param = param;
    }

    public String getSubName() {
        return subName;
    }

    public String getContent() {
        return content;
    }
}

编辑：根据要求，这里是animationUp文件和animationDown文件的代码：

animationUp.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:fillAfter="true" >

    <scale
        android:duration="200"
        android:fromXScale="1.0"
        android:fromYScale="1.0"
        android:interpolator="@android:anim/linear_interpolator"
        android:toXScale="1.0"
        android:toYScale="0.0" />

</set>

animationDown.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:fillAfter="true">

    <scale
        android:duration="200"
        android:fromXScale="1.0"
        android:fromYScale="0.0"
        android:interpolator="@android:anim/accelerate_interpolator"
        android:toXScale="1.0"
        android:toYScale="1.0" />

</set>

【问题讨论】：

标签： java android

【解决方案1】：

感谢 Ashish，我用一个简单的逻辑解决了这个问题。这是我重新定义的 changeStateOfItemsInLayout 函数代码：

private void changeStateOfItemsInLayout(ListItem listItem, int p) {
        for (int x = 0; x < listItems.size(); x++) {
            if (x == p) {
                listItem.setShouldBeExpanded(true);
                //Since this is the tapped item, we will skip
                //the rest of loop for this item and set it expanded
                continue;
            }
            listItems.get(x).setShouldBeExpanded(false);
        }
    }

此功能负责折叠所有其他项目。它检查哪个选项被点击并展开它（如果已经展开，我们不会从 OnBindViewHolder 函数调用这个函数）并折叠所有其他选项。

这是我的完整适配器代码：

public class DataAdapter extends RecyclerView.Adapter<DataAdapter.ViewHolder> {
    private ArrayList<ListItem> android_versions;
    private List<ListItem> listItems;
    private LayoutInflater layoutInflater;
    private Animation animationUp, animationDown;
    private Context context;
    private final int COUNTDOWN_RUNNING_TIME = 300;

    public DataAdapter(Context context, java.util.List<ListItem> android_versions,
                       Animation animationUp, Animation animationDown) {
        this.context = context;
        this.listItems = android_versions;
        this.animationDown = animationDown;
        this.animationUp = animationUp;
    }

    @Override
    public DataAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.row_layout, viewGroup, false);
        return new ViewHolder(view);
    }

    public String getRandomColor(int a){
        String colors[] = {"#ef5350","#f44336","#ef5350"};
        return colors[a];
    }

    private void changeStateOfItemsInLayout(ListItem listItem, int p) {
        for (int x = 0; x < listItems.size(); x++) {
            if (x == p) {
                listItem.setShouldBeExpanded(true);
                //Since this is the tapped item, we will skip
                //the rest of loop for this item and set it expanded
                continue;
            }
            listItems.get(x).setShouldBeExpanded(false);
        }
    }


    @Override
    public void onBindViewHolder(final ViewHolder holder, int i) {
        ListItem listItem = listItems.get(i);
        if (i%2==2)
            holder.itemView.setBackgroundColor(Color.parseColor(getRandomColor(0)));
        else if (i%2==1)
            holder.itemView.setBackgroundColor(Color.parseColor(getRandomColor(1)));
        else if (i%2==0)
            holder.itemView.setBackgroundColor(Color.parseColor(getRandomColor(2)));

        holder.tv_android.setText(listItem.getSubName());
        holder.contentLayout.setText(listItem.getContent());
        if(listItem.getShouldBeExpanded()){
            holder.contentLayout.setVisibility(View.VISIBLE);
            holder.contentLayout.startAnimation(animationDown);
        }else{
            holder.contentLayout.startAnimation(animationUp);
            CountDownTimer countDownTimerStatic = new CountDownTimer(COUNTDOWN_RUNNING_TIME, 16) {
                @Override
                public void onTick(long millisUntilFinished) {}
                @Override
                public void onFinish() {
                    holder.contentLayout.setVisibility(View.GONE);
                }
            };
            countDownTimerStatic.start();
        }

        holder.expandit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (holder.contentLayout.isShown()) {
                    listItems.get(holder.getLayoutPosition()).setShouldBeExpanded(false);
                } else {
                    listItems.get(holder.getLayoutPosition()).setShouldBeExpanded(true);
                    changeStateOfItemsInLayout(listItems.get(holder.getLayoutPosition()),holder.getLayoutPosition());
                }
                notifyDataSetChanged();
            }
        });
    }
    @Override
    public int getItemCount() {
        return listItems.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder{
        TextView tv_android;
        private TextView contentLayout;
        RelativeLayout expandit;
        public ViewHolder(View view) {
            super(view);
            tv_android = (TextView)view.findViewById(R.id.tv_android);
            contentLayout = (TextView) view.findViewById(R.id.content);
            expandit = (RelativeLayout)view.findViewById(R.id.expandit);
        }
    }
}

【讨论】：

能否提供animationUp和animationDown的代码？
@Fathimakm 我已经编辑了帖子以添加您的代码。请检查！

【解决方案2】：

在我假设是模型类的 ListItem 类中，添加一个新的布尔变量 shouldBeExpanded 并将其默认值设置为 false，然后编写它的 getter 和 setter。现在在您的适配器中，在 onBindViewHolder 中编写以下代码

if(listItem.shouldBeExpanded()){
//write your code to expand it
}else{
//write the code to collapse
}

现在在代码部分，在一些展开布局的 onClick 中，将此 lisItem 的此变量设置为 true，并调用一个函数，将 listItem 中的所有其他项目设置为 false 的 shouldBeExpanded..通过调用下面的函数changeStateOfItemsInLayout(listItem)。现在称为 notifyDataSetChanged()。

private void changeStateOfItemsInLayout(ListItem listItem){
for(int i=0;i<listItems.size();i++){
if(listItems.get(i)==listItem)
listItem.get(i).setShouldBeExpanded(true);
}else{
listItem.get(i).setShouldBeExpanded(false);
}
}

这应该可以解决您的目的。

【讨论】：

对我不起作用。当我点击一个项目时，它会扩展一小会儿，然后立即折叠，除了最后一个项目。
出现问题。我一直在使用 listItem 作为最终版本。但删除了 final 关键字。问题仍然存在。
我还是没看到
就在onBindViewHolder函数上方
在调用 notifyDataSetChanges() 后，您能否调试一下，看看 shouldBeExpanded 的值对于正确的列表项是否为 true，而对于其他列表项是否为 false。

【解决方案3】：

我花了几个小时摆弄 ExpandableRecyclerAdapter 代码。但这真的很简单。在您的活动中，您有展开/折叠事件的侦听器，当前父列表项位置正在展开/折叠。跟踪 currentExpandedPosition 并调用适配器 collapseParent 以折叠先前展开的项目。 5行代码，完美的手风琴效果。

private currentExpandedPosition = -1;

        mAdapter.setExpandCollapseListener(new ExpandableRecyclerAdapter.ExpandCollapseListener() {
        @Override
        public void onListItemExpanded(int position) {

            if (currentExpandedPosition >= 0){
                mAdapter.collapseParent(currentExpandedPosition);
            }
            currentExpandedPosition = position;
        }

        @Override
        public void onListItemCollapsed(int position) {

           currentExpandedPosition = -1;
        }
    });

【讨论】：