[ChipGroup] Copy last value instead IndexOutOfBoundsException

Description: When iterating over collection with indices (in case collection size is bigger than 1) if we add +1 index there’ll be copy chip of last value instead IndexOutOfBoundsException.

Source code:

for (i in tags.indices + 1) {
    val chip = Chip(tagsChipGroup.context).apply {
        text = tags[i]
        setChipBackgroundColorResource(R.color.colorCardBackground)
        isClickable = true
        textSize = resources.getDimension(R.dimen.tag_text_size)
     }
     tagsChipGroup.addView(chip)
}

Android API version: 29

Material Library version: 1.1.0-beta02

Device: Pixel 2 XL

[hunterstich]

Hey @papuge! This looks like a Kotlin questions that doesn’t really relate to our library.

With that said, in your original code snippet you have for (i in tags.indices + 1). What tags.indices + 1 is actually doing is creating an IntArray of the indices in your tags Collection and then appending the Int 1 to that array, leaving you with the equivalent of for (i in [0, 1, 2, 1] (given a tags array with 3 items in it). This is more obvious if you replace 1 with something like 99. tags.indices + 99 creates an IntArray of the indices in tags and appends the Int 99, leaving you with [0, 1, 2, 99]. In that case, you would get an IndexOutOfBounds exception if your tags array had less than 99 items in it.

Hopefully that helps. I’m going to go a head and close this issue.

[papuge]

@hunterstich this is tag collection val tags = arguments?.getStringArrayList(ARG_TAGS)?.toList()!! and piece of OnCreateView() method

        val tags = arguments?.getStringArrayList(ARG_TAGS)?.toList()!!
        val note = arguments?.getParcelable<Note>(ARG_NOTE)
        note.run {
            headerTextView.text = this?.title ?: ""
            contentTextView.text = this?.content ?: ""

            Log.d("NoteFragment", "tags from viewModel: $tags")

            if (tags.isNotEmpty()) {
                for (tag in tags) {
                    val chip = Chip(tagsChipGroup.context).apply {
                        text = tag
                        setChipBackgroundColorResource(R.color.colorCardBackground)
                        isClickable = true
                        textSize = resources.getDimension(R.dimen.tag_text_size)
                    }
                    tagsChipGroup.addView(chip)
                }
            } else {
                view.findViewById<HorizontalScrollView>(R.id.tags_scroll).visibility = GONE
            }
        }

        editNoteButton.setOnClickListener {
            redirectToEditFragment(note!!, tags)
        }