没有子级的 ExpandableListView 抛出 indexOutOfBoundsException

Posted 2023-05-07

【中文标题】没有子级的 ExpandableListView 抛出 indexOutOfBoundsException

【英文标题】：ExpandableListView with no children throws indexOutOfBoundsException

【发布时间】：2020-10-10 22:44:04

【问题描述】：

我有一个ExpandableListView，其中有些组有孩子，有些没有，我需要做的是只扩展有孩子的组。

body 数组元素的一部分是空的，因此，我得到一个 IndexOutOfBoundsException

    class ExpandableInnerCartAdapter(
        var context: Context,
        var expandableListView: ExpandableListView,
        var header: MutableList<Cart>,
        val isTerminadoFragment:Boolean
    ) : BaseExpandableListAdapter() 
    
        val map = SparseBooleanArray()
        var body: List<List<String>> = listOf()
    
        override fun getGroup(groupPosition: Int): Cart 
           return header[groupPosition]
        
    
        override fun isChildSelectable(groupPosition: Int, childPosition: Int): Boolean 
           return true
        
    
        override fun hasStableIds(): Boolean 
            return false
        
    
        fun getCart(): MutableList<Cart> = header
        fun getCheckedArray():SparseBooleanArray = map
    
        override fun getGroupView(
            groupPosition: Int,
            isExpanded: Boolean,
            convertView: View?,
            parent: ViewGroup?
        ): View 
    
            var convertView = convertView
            if(convertView == null)
                val inflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
                convertView = inflater.inflate(R.layout.layout_group,null)
            
            val item = header[groupPosition]
            body = listOf(item.optionList)
            expandableListView.expandGroup(groupPosition)
            expandableListView.setGroupIndicator(null)
            convertView.item_name.text = item.productName
           
            return convertView
    
        
    
        override fun getChildrenCount(groupPosition: Int): Int 
            return body[groupPosition].size
        
    
        override fun getChild(groupPosition: Int, childPosition: Int): Any 
            return body[groupPosition][childPosition]
        
    
        override fun getGroupId(groupPosition: Int): Long 
            return groupPosition.toLong()
        
    
        override fun getChildView(
            groupPosition: Int,
            childPosition: Int,
            isLastChild: Boolean,
            convertView: View?,
            parent: ViewGroup?
        ): View 
            var convertView = convertView
            if(convertView == null)
                val inflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
                convertView = inflater.inflate(R.layout.layout_child,null)
            
            if(getChildrenCount(groupPosition) > 0)
                val title = convertView?.findViewById<TextView>(R.id.tv_title)
                title?.text = "Opción $childPosition+1 -> $getChild(groupPosition,childPosition)"
            
    
            return convertView!!
        
    
        override fun getChildId(groupPosition: Int, childPosition: Int): Long 
            return childPosition.toLong()
        
    
        override fun getGroupCount(): Int 
            return header.size
        
    

当没有小组有孩子并尝试这样做时，似乎会发生错误

    expandableListView.expandGroup(groupPosition)

我已尝试使用 if 语句解决此问题：

    if(body.isNotEmpty())
        expandableListView.expandGroup(groupPosition)
    

但是这个解决方案不起作用。

如何避免没有孩子的群体？

谢谢

【参考方案1】：

当您使用 Kotlin 时，您可以使用许多有用的扩展功能。其中之一是filter，当然您可以为其指定条件。

解决方案是从您设置为新 body 值的列表中过滤掉空数组：

    body = listOf(item.optionList).filter  it.isNotEmpty() 

过滤函数定义可见here。