android - SelectionTracker 未在我的 Recyclerview 中选择任何内容

Question

当我点击项目时没有任何反应我尝试更改颜色、显示所选元素的数量、显示日志什么都没有发生

我的ViewHolder

class MyViewHolder(view: View) : RecyclerView.ViewHolder(view) {

val name: TextView = view.list_item_name
val phone: TextView = view.list_item_phone

// More code here
fun getItemDetails(): ItemDetailsLookup.ItemDetails<Long> =
    object : ItemDetailsLookup.ItemDetails<Long>() {
        override fun getSelectionKey(): Long? = itemId

        override fun getPosition(): Int = adapterPosition

    }

}

我的 ItemDetailsLookup

class MuLookup(private val rv: RecyclerView) : ItemDetailsLookup<Long>() {
    override fun getItemDetails(event: MotionEvent): ItemDetails<Long>? {
        val view = rv.findChildViewUnder(event.x, event.y)
        if (view != null) {
            return (rv.getChildViewHolder(view) as MyViewHolder)
                .getItemDetails()
        }
        return null
    }
}

我的适配器

class PersonAdapter(
    private val listItems: List<Person>,
    private val context: Context
) : RecyclerView.Adapter<MyViewHolder>() {

    init {
        setHasStableIds(true)
    }

    private var tracker: SelectionTracker<Long>? = null

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
        return MyViewHolder(
            LayoutInflater.from(context)
                .inflate(R.layout.list_item_jf, parent, false)
        )
    }

    override fun getItemCount(): Int {
        return listItems.size
    }

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        holder.name.text = listItems[position].name
        holder.phone.text = listItems[position].phone

        val parent = holder.name.parent as LinearLayout

        if (tracker!!.isSelected(position.toLong())) {
            parent.background = ColorDrawable(
                Color.parseColor("#80deea")
            )
        } else {
            Timber.i("zeze ${tracker!!.selection}")
            // Reset color to white if not selected
            parent.background = ColorDrawable(Color.WHITE)
        }

    }

    override fun getItemId(position: Int): Long {
        return position.toLong()
    }

    fun setTracker(tracker: SelectionTracker<Long>?) {
        this.tracker = tracker
    }

}

我的 Activity

class MainActivity : AppCompatActivity() {

    private var tracker: SelectionTracker<Long>? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        if (savedInstanceState != null)
            tracker?.onRestoreInstanceState(savedInstanceState)

        val myList = listOf(
            Person("Alice", "555-0111"),
            Person("Bob", "555-0119"),
            Person("Carol", "555-0141"),
            Person("Dan", "555-0155"),
            Person("Eric", "555-0180"),
            Person("Craig", "555-0145")
        )

        my_rv.layoutManager = LinearLayoutManager(this)
        my_rv.setHasFixedSize(true)

        val adapter = PersonAdapter(myList, this)
        my_rv.adapter = adapter

        tracker = SelectionTracker.Builder<Long>(
            "selection-1",
            my_rv,
            StableIdKeyProvider(my_rv),
            MuLookup(my_rv),
            StorageStrategy.createLongStorage()
        ).withSelectionPredicate(
            SelectionPredicates.createSelectAnything()
        ).build()

        tracker?.addObserver(
            object : SelectionTracker.SelectionObserver<Long>() {
                override fun onSelectionChanged() {
                    val nItems: Int? = tracker?.selection?.size()

                    if (nItems != null && nItems > 0) {

                        // Change title and color of action bar

                        title = "$nItems items selected"
                        supportActionBar?.setBackgroundDrawable(
                            ColorDrawable(Color.parseColor("#ef6c00"))
                        )
                    } else {

                        // Reset color and title to default values

                        title = "RVSelection"
                        supportActionBar?.setBackgroundDrawable(
                            ColorDrawable(Color.parseColor("#126c00"))
                        )
                    }
                }
            })

        adapter.setTracker(tracker)


    }

    override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)

        tracker?.onSaveInstanceState(outState)
    }
}

谢谢

解决方案:Tracker 有效

override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
    holder.name.text = listItems[position].name
    holder.phone.text = listItems[position].phone

    val parent = holder.name.parent as LinearLayout

    holder.name.setOnClickListener {
        Timber.i("zeze ici")
        if (tracker!!.isSelected(position.toLong())) {
            Timber.i("zeze la")
            parent.background = ColorDrawable(
                Color.parseColor("#80deea")
            )
        } else {
            Timber.i("zeze ${tracker!!.selection}")
            // Reset color to white if not selected
            parent.background = ColorDrawable(Color.WHITE)
        }
    }
}

supportActionBar 中显示颜色变化和项目数量

Answer 1

问题是 Recyclerview 选择只有在最初选择了一个项目时才会激活，然后您只需点击它们就可以选择其他项目。

如果您总是需要用户选择一个项目，或者让用户选择一个项目，您可以使用 selectionTracker 从 recyclerview 中初始选择一个项目:

selectionTracker.select(someItemId)

现在，您只需轻按一下即可从列表中选择其他项目。