【发布时间】：2020-01-17 13:59:12
【问题描述】：
我是新手。滚动我的 ListView 后，与我在自动选择之前选择的项目处于“相同位置”的项目。 （相同的位置，我的意思是屏幕中的位置而不是数据库中的位置。）我之前有过这个问题，因为我在 OnItemClickListener 中通过它们的 ListView 索引来选择项目。然而，我再次面临这个问题，尽管我以我认为的正确方式做这件事。
当我点击 ListView 中的项目时，我得到它的唯一 ID，并基于此我将这个项目（数据库中这一行的）的 SELECTED 值更改为 0 或 1（取决于它是否被点击） .之后，我将背景颜色切换为灰色（或返回白色）。这是在区分 SELECTED 属性的 CursorAdapter 中处理的。
这是我的代码。
MainActivity.kt 中的 OnCreate
val dbHelper = DBHelper(this)
val db = dbHelper.writableDatabase
val myCursor = db.rawQuery("SELECT * FROM ${ContractClass.FeedReaderContract.TABLE_NAME}", null)
val myAdapter = CursorAdapter(this, myCursor)
myListView.adapter = myAdapter
myListView.setOnItemClickListener { _, view, _, _ ->
val text = view.txtName.text
val select = "${ContractClass.FeedReaderContract.COLUMN_NAME_ENWORD} MATCH ?"
val selectCursor = db.query(
ContractClass.FeedReaderContract.TABLE_NAME, // The table to query
null, // The array of columns to return (pass null to get all)
select, // The columns for the WHERE clause
arrayOf("$text"), // The values for the WHERE clause
null, // don't group the rows
null, // don't filter by row groups
null // The sort order
)
with(selectCursor) {
while (moveToNext()) {
val itemSel = getInt(getColumnIndexOrThrow(ContractClass.FeedReaderContract.COLUMN_NAME_SELECTED))
if (itemSel == 1){
val values = ContentValues().apply {
put(ContractClass.FeedReaderContract.COLUMN_NAME_SELECTED, 0)
}
val count = db.update(
ContractClass.FeedReaderContract.TABLE_NAME, values, select, arrayOf("$text"))
}else{
val values = ContentValues().apply {
put(ContractClass.FeedReaderContract.COLUMN_NAME_SELECTED, 1)
}
val count = db.update(
ContractClass.FeedReaderContract.TABLE_NAME, values, select, arrayOf("$text"))
}
}
}
}
CursorAdapter.kt
class CursorAdapter(context: Context, cursor: Cursor) : CursorAdapter(context, cursor, 0) {
// The newView method is used to inflate a new view and return it,
// you don't bind any data to the view at this point.
override fun newView(context: Context, cursor: Cursor, parent: ViewGroup): View {
if (cursor.getInt(cursor.getColumnIndexOrThrow(ContractClass.FeedReaderContract.COLUMN_NAME_SELECTED)) == 0){
return LayoutInflater.from(context).inflate(R.layout.row_list_row, parent, false)
}else{
return LayoutInflater.from(context).inflate(R.layout.user_list_row_selected, parent, false)
}
}
// The bindView method is used to bind all data to a given view
// such as setting the text on a TextView.
override fun bindView(view: View, context: Context, cursor: Cursor) {
// Find fields to populate in inflated template
val tvBody = view.findViewById<View>(R.id.txtName) as TextView
val tvPriority = view.findViewById<View>(R.id.txtComment) as TextView
val tvPriority2 = view.findViewById<View>(R.id.txtThird) as TextView
val tvPriority3 = view.findViewById<View>(R.id.txtThi) as TextView
// Extract properties from cursor
val body = cursor.getString(cursor.getColumnIndexOrThrow(ContractClass.FeedReaderContract.COLUMN_NAME_ENWORD))
val priority = cursor.getString(cursor.getColumnIndexOrThrow(ContractClass.FeedReaderContract.COLUMN_NAME_DEFN))
val priority2 = cursor.getInt(cursor.getColumnIndexOrThrow(ContractClass.FeedReaderContract._id))
val priority3 = cursor.getInt(cursor.getColumnIndexOrThrow(ContractClass.FeedReaderContract.COLUMN_NAME_SELECTED))
// Populate fields with extracted properties
tvBody.text = body
tvPriority.text = priority.toString()
tvPriority2.text = priority2.toString()
tvPriority3.text = priority3.toString()
}
}
数据库表创建
private val SQL_CREATE_ENTRIES =
"CREATE VIRTUAL TABLE ${ContractClass.FeedReaderContract.TABLE_NAME} USING fts4(" +
"${ContractClass.FeedReaderContract._id}," +
"${ContractClass.FeedReaderContract.COLUMN_NAME_ENWORD} TEXT," +
"${ContractClass.FeedReaderContract.COLUMN_NAME_DEFN} TEXT," +
"${ContractClass.FeedReaderContract.COLUMN_NAME_SELECTED} INTEGER)"
我在这里找到了类似的帖子：List view with simple cursor adapter items checked are un-checked during scroll 但我认为，他们建议了我已经完成的工作。
感谢您的帮助。
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标签： database sqlite android-studio kotlin android-listview