Material 筹码：java.lang.IndexOutOfBoundsException 当检查任何筹码时

Question

我有一个 chip group，我的 AddItemFragment 里有一些筹码。我正在以编程方式创建这些芯片。更准确地说，这是我创建它们的代码：

     mViewModel.categories.observe(viewLifecycleOwner) { resource ->
                handleResource(
                    resource = resource,
                    successFunc = {
                        setCategoryChips(resource.data!!)
                    },
                    errorFunc = {
                        requireView().snack(resource.message!!, R.color.color_danger)
                    }
                )            
        }
    private fun setCategoryChips(categories: List<Kitchen>) {
        for (i in categories.indices) {
            val chip = layoutInflater.inflate(R.layout.my_chip, binding.chipGroup, false) as Chip
            if (i == 0) {
                selectedChip = chip.text.toString()
                chip.isChecked = true
            }
            chip.text = categories[i].name
            binding.chipGroup.addView(chip)
        }
        binding.chipGroup.setOnCheckedChangeListener { group, checkedId ->
            if (group.childCount > 0) {
                selectedChip = (group.get(checkedId -1) as Chip).text.toString()
                Log.i(TAG, "setCategoryChips: $selectedChip")
            }
        }
    }

如您所见，我正在从服务器获取一个列表，然后根据该列表创建筹码。我正在使用以下方式获取已检查芯片的文本：

binding.chipGroup.setOnCheckedChangeListener { group, checkedId ->
            if (group.childCount > 0) {
                selectedChip = (group.get(checkedId -1) as Chip).text.toString()
                Log.i(TAG, "setCategoryChips: $selectedChip")
            }
        }

我第一次导航到 AddItemFragment 时，此方法按预期工作。但是，当我导航到另一个目的地然后再次导航回 AddItemFragment 时，如果我检查任何筹码，我都会收到此错误

 java.lang.IndexOutOfBoundsException: Index: 29, Size: 28
        at androidx.core.view.ViewGroupKt.get(ViewGroup.kt:32)
        at com.example.semekyepeti.view.fragments.sellerflow.AddItemFragment$setKitchenChips.onCheckedChanged(AddItemFragment.kt:183)
        at com.google.android.material.chip.ChipGroup.setCheckedId(ChipGroup.java:362)
        at com.google.android.material.chip.ChipGroup.setCheckedId(ChipGroup.java:355)
        at com.google.android.material.chip.ChipGroup.access0(ChipGroup.java:56)
        at com.google.android.material.chip.ChipGroup$CheckedStateTracker.onCheckedChanged(ChipGroup.java:546)
        at com.google.android.material.chip.Chip.setChecked(Chip.java:714)
        at android.widget.CompoundButton.toggle(CompoundButton.java:135)
        at android.widget.CompoundButton.performClick(CompoundButton.java:140)

我意识到当我导航到另一个目的地然后再次导航回 AddItemFragment 时，checkedId 会自行递增。

 I/AddItemFragment: navigate 0 time
 I/AddItemFragment: checkedId: 2
 I/AddItemFragment: item count: 28

 I/AddItemFragment: navigate 1 time
 I/AddItemFragment: checkedId: 30
 I/AddItemFragment: item count: 28

所以我将 checkedId -1 更改为 (checkedId - listCount * navigateCount) -1 来处理这个问题：

      binding.chipGroup.setOnCheckedChangeListener { group, checkedId ->
            if (group.childCount > 0) {
                selectedChip =
                    (group.get((checkedId - 28 * navigateCount) - 1) as Chip).text.toString() //workaround
            }
        }

但是我知道这是inefficient.I想要得到被勾选的芯片的文本。我该如何解决？

Answer 1

你得到的 checkedId 显然是一个视图 ID，你应该用 findViewById 获取实际的筹码。您将其用作视图组中的索引，不一定会匹配（但有时会匹配！）

没有文档实际上没有解释这个

Material 筹码：java.lang.IndexOutOfBoundsException 当检查任何筹码时

Material Chips: java.lang.IndexOutOfBoundsException when checked any of the chips

android

kotlin

material-design

material-ui