以编程方式向 RecyclerView 项目添加一些视图会创建一个已知错误

Question

所以我正在创建一个待办事项应用程序，用户可以在其中设置优先级，优先级星号是通过绑定适配器以编程方式添加的，但是当滚动任务回收器视图时，星号为零的任务也显示星号，其中检查日志显示为零星星。此外，仅当我滚动到带星标的项目然后开始严格滚动时才会出现此错误

应用刚刚启动

已滚动到带有任务星标的项目

严格滚动后

我已尝试在每次更新项目时创建新的 ArrayList

片段代码：

viewModel.taskCategory.observe(viewLifecycleOwner, Observer { taskCategoryPair ->
            taskCategoryPair?.let {
                Log.i("HomeFragment","Submitting New List")
                viewModel.filterDataFinish()
                adaptor.submitList(it)
            }
        })

RecyclerView 绑定代码：

 RecyclerView.ViewHolder(binding.root) {
        fun bind(
            task: ToDo,
            category: Category,
            clickListener: MiscellaneousUtils.GetIdFromClick
        ) {
            binding.task = task
            binding.category = category
            binding.clickListener = clickListener
            binding.onCheckChangeListener = categorizedTasksClickListeners

            binding.root.setOnLongClickListener {
                categorizedTasksClickListeners.onLongClickItem(adapterPosition,it)
                true
            }

            binding.executePendingBindings()
        }

添加星星的BindingAdapter函数：

@BindingAdapter("app:setPriority")
fun LinearLayoutCompat.setPriority(task: ToDo) {
    if (task.priorityStars == 0)
        return

    val previousStarContainer = findViewWithTag<LinearLayout>("starContainerLayout")

    if (previousStarContainer != null) {
        removeView(previousStarContainer)
    }

    val starContainer = LinearLayout(context)
    starContainer.tag = "starContainerLayout"
    starContainer.layoutParams = LinearLayoutCompat.LayoutParams(
        ViewGroup.LayoutParams.WRAP_CONTENT,
        ViewGroup.LayoutParams.WRAP_CONTENT
    )

    for (count in 1..task.priorityStars) {
        val starView = ImageView(context)
        starView.setImageResource(R.drawable.task_star)
        starView.layoutParams = LinearLayoutCompat.LayoutParams(
            ViewGroup.LayoutParams.WRAP_CONTENT,
            ViewGroup.LayoutParams.WRAP_CONTENT
        )
        starContainer.addView(starView)
    }
    addView(starContainer)

}

Answer 1

Recycler 回收视图 :) - 它使用相同的视图来显示多个数据！这意味着视图可用于显示带有星星的对象 - 所以在 onBindViewHolder 上显示星星。然后相同的视图（现在有星星）将用于显示不同的对象（没有星星对象）——这意味着在 onBindViewHolder 上你现在需要隐藏星星，我敢打赌你没有； )

正如我所说，如果你没有星星，你就不会删除之前的开始：

if (task.priorityStars == 0)
        return

将您的代码更改为：

@BindingAdapter("app:setPriority")
fun LinearLayoutCompat.setPriority(task: ToDo) {
    val previousStarContainer = findViewWithTag<LinearLayout>("starContainerLayout")

    if (previousStarContainer != null) {
        removeView(previousStarContainer)
    }

    if (task.priorityStars == 0)
        return

    val starContainer = LinearLayout(context)
    starContainer.tag = "starContainerLayout"
    starContainer.layoutParams = LinearLayoutCompat.LayoutParams(
        ViewGroup.LayoutParams.WRAP_CONTENT,
        ViewGroup.LayoutParams.WRAP_CONTENT
    )

    for (count in 1..task.priorityStars) {
        val starView = ImageView(context)
        starView.setImageResource(R.drawable.task_star)
        starView.layoutParams = LinearLayoutCompat.LayoutParams(
            ViewGroup.LayoutParams.WRAP_CONTENT,
            ViewGroup.LayoutParams.WRAP_CONTENT
        )
        starContainer.addView(starView)
    }
    addView(starContainer)

}

以编程方式向 RecyclerView 项目添加一些视图会创建一个已知错误

Adding Some View to RecyclerView item programmatically creates an known bug

android

arraylist

android-recyclerview

android-binding-adapter

android-livedata