我正在研究一个Android项目,其中正在从子活动中更新ListFragment。但是,尽管更新后元素的数量是正确的,但元素本身不是。不正确的元素被放入列表中并且彼此重复。
问题是,子活动修改了文件,并调用populate()函数之后,然后我回到片段所在的主活动中,出现了问题。例如,开始时它们按以下顺序排列:[1, 2, 3]
现在子活动中的文件操作将删除项目“ 1”(不是直接调用remove,而是删除该文件,并且populate()
函数(下面列出)将生成不包含该元素的列表),并且应该成为[2, 3]
。但它改为[1, 2]
。
并且在通过按钮调用了完全刷新之后,包括清除并重新填充MetadataManager.packMap
和PackListManager.onlineList
,PackListManager.localList
,然后重新启动MainActivity,它会恢复正常。
现在我们有[2, 3]
。子活动中的另一个文件操作应返回“ 1”,并且应再次变为[1, 2, 3]
。但是,它变成[2, 3, 3]
。
这些元素来自一个ArrayList。这是ListFragment的类:
class PackListFragment : ListFragment() {
private lateinit var dataList: ArrayList<PackageMetadata>
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val index = arguments?.getInt(ARG_SECTION_NUMBER) ?: 1
if (index == 1){
dataList = PackListManager.onlineList
} else {
dataList = PackListManager.localList
}
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val adapter = PackMetadataAdapter(activity as Context, dataList)
listAdapter = adapter
return inflater.inflate(R.layout.fragment_main, container, false)
}
override fun onResume() {
(listAdapter as ArrayAdapter<PackageMetadata>).notifyDataSetChanged()
super.onResume()
}
我的ListView使用自定义适配器。这是适配器:
class PackMetadataAdapter (context : Context, val values : List<PackageMetadata>)
: ArrayAdapter<PackageMetadata>(context, -1, values) {
override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
if (convertView == null) {
val inflater = context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
/*val rowView : View = inflater.inflate(android.R.layout.simple_list_item_1, parent, false)
val text1 = rowView.findViewById(android.R.id.text1) as TextView
text1.text = values[position].Name_LO*/
val metadata = values[position]
val rowView: View = inflater.inflate(R.layout.listitem_route, parent, false)
val textTitle = rowView.findViewById<View>(R.id.textTitle) as TextView
val textAuthor = rowView.findViewById(R.id.textAuthor) as TextView
val textVersion = rowView.findViewById(R.id.textVersion) as TextView
val textTimestamp = rowView.findViewById(R.id.textTimestamp) as TextView
val imageView: ImageView = rowView.findViewById<View>(R.id.imageThumbnail) as ImageView
textTitle.text = metadata.Name_LO
textAuthor.text = metadata.Author.Name_LO
textVersion.text = metadata.Version.get()
textTimestamp.text = SimpleDateFormat("yyyy-MM-dd", Locale.US)
.format(values[position].Timestamp)
DownloadImageTask(imageView).execute(metadata.Thumbnail)
return rowView
}
return convertView
}
}
并且单例中的列表是这样填充的:
object PackListManager {
const val LOGCAT_TAG = "BCSPackListMan"
val localList : ArrayList<PackageMetadata> = ArrayList()
var onlineList : ArrayList<PackageMetadata> = ArrayList()
fun populate(){
localList.clear(); onlineList.clear()
val localPacks = HashMap(PackLocalManager.getLocalPacks().map {
val parts = stripExtension(it.nameWithoutExtension).split("_")
if (parts.count() > 1) {
parts[0] to Version(parts[1])
} else {
it.nameWithoutExtension to Version("0.0")
}
}.toMap())
for (pack in MetadataManager.packMap){
if (localPacks.containsKey(pack.key)){
Log.i(LOGCAT_TAG, "Pack "+pack.key+" found on local disk")
if (localPacks[pack.key]!! < pack.value.Version){
Log.i(LOGCAT_TAG, "Pack "+pack.key+" can be updated")
}
localPacks.remove(pack.key)
localList.add(pack.value)
} else {
Log.i(LOGCAT_TAG, "Pack "+pack.key+" not installed")
onlineList.add(pack.value)
}
}
}
通过检查logcat,我可以说polulate()
函数生成的列表是正确的,而如果未调用上述手动刷新,则MetadataManager.packMap shuold保持不变。
我已经在Google上搜索了此类问题,但似乎找不到很好的答案。我为发布这么长的代码感到非常抱歉,但我自己却无法弄清楚。任何帮助将不胜感激!
顺便说一句,我不是母语人士,对帖子中的错误感到抱歉。
已解决,谢谢KostyaBakay!
将ListView替换为RecyclerView即可立即解决问题。我真的不应该对已弃用的组件给予过多信任...