ItemTouchHelper不会启动卷帘

Question

我在RecyclerView上查找了很多关于滑动功能的教程。当我连接ItemTouchHelper时，它对ViewHolder没有影响。

我已经在onSwiped方法中放置了一个断点，但当我试图滑动时，它甚至都不会到达那里。我做了一个新项目，用一些视图持有者实现了一个随机的回收视图。我连接了ItemTouchHelper，也遇到了同样的问题。

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    val model = ViewModelProviders.of(this)[ViewModel::class.java]
    val dues = model.dues
    val adapter = Adapter<Due>(R.layout.card_view_dues, fragmentManager!!)
    dues.observe(this,
        Observer<MutableList<Due>> {
            adapter.list = it
        }
    )
    val itemTouchHelper = object: SimpleCallback(0, LEFT and RIGHT) {
        override fun onMove(
            recyclerView: RecyclerView,
            viewHolder: RecyclerView.ViewHolder,
            target: RecyclerView.ViewHolder
        ) = false

        override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
            dues.value?.removeAt(viewHolder.adapterPosition) //set breakpoint here
            adapter.notifyDataSetChanged()
        }
    }
    ItemTouchHelper(itemTouchHelper).attachToRecyclerView(recyclerView)
    recyclerView.apply {
        layoutManager = LinearLayoutManager(activity!!.applicationContext)
        setHasFixedSize(false)
        this.adapter = adapter
    }
}

我还替换了：

ItemTouchHelper(itemTouchHelper).attachToRecyclerView(recyclerView)

使用

ItemTouchHelper(itemTouchHelper).attachToRecyclerView(activity!!.findViewById<RecyclerView>(R.id.recyclerView))

但它似乎仍然不起作用。到底出了什么问题？

Answer 1

您向SimpleCallback提供了错误的参数

    val itemTouchHelper = object: SimpleCallback(0, LEFT and RIGHT) {

相反，你应该

    val itemTouchHelper = object: SimpleCallback(0, LEFT or RIGHT) {