I have a dialog to select more than one days of a week as follows:
class DialogSettingsEnabledDays : DialogFragment() {
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
return activity.let {
val selectedDaysValue = BooleanArray(7) { _ -> false }
val selectedDaysIndex = ArrayList<Int>()
val daysToIndexMap = mutableMapOf<String, Int>()
val indexToDaysMap = mutableMapOf<Int, String>()
val daysArray = resources.getStringArray(R.array.days_medium)
for (i in 0..6) {
daysToIndexMap[daysArray[i]] = i
indexToDaysMap[i] = daysArray[i]
}
val prefs = it!!.getSharedPreferences(getString(R.string.shared_prefs_settings), Context.MODE_PRIVATE)
val selectedDaysString = prefs.getString("enabled_days", getString(R.string.default_enabled_days))
val selectedDays = selectedDaysString!!.split(", ")
for (day in selectedDays) {
selectedDaysValue[daysToIndexMap.getValue(day)] = true
selectedDaysIndex.add(daysToIndexMap.getValue(day))
}
val enabledDaysBuilder = AlertDialog.Builder(it)
enabledDaysBuilder
.setTitle(R.string.settings_enabled_days)
.setMultiChoiceItems(R.array.days_long, selectedDaysValue) { _, which, isChecked ->
if (isChecked)
selectedDaysIndex.add(which)
else if (selectedDaysIndex.contains(which))
selectedDaysIndex.remove(Integer.valueOf(which))
}
.setPositiveButton(R.string.dialog_ok) { _, _ ->
if (selectedDaysIndex.isEmpty()) {
Toast.makeText(it, "Select atleast one day !!", Toast.LENGTH_SHORT).show()
} else {
selectedDaysIndex.sort()
val selectedDaysList = mutableListOf<String>()
for (i in selectedDaysIndex) {
selectedDaysList.add(indexToDaysMap.getValue(i))
}
val editor = prefs.edit()
editor
.putString("enabled_days", selectedDaysList.joinToString())
.apply()
val enabledDays = it.findViewById<LinearLayout>(R.id.settings_enabled_days)
enabledDays.findViewById<TextView>(R.id.secondary_text).text = selectedDaysList.joinToString()
}
}
.setNegativeButton(R.string.dialog_cancel) { _, _ -> /* do nothing */ }
enabledDaysBuilder.create()
}
}
}
And I am calling this dialog in this way from my activity:
findViewById<LinearLayout>(R.id.settings_enabled_days)
.setOnClickListener {
DialogSettingsEnabledDays().show(this.supportFragmentManager, null)
}
My problem is that my selection of days resets to default on rotation. By default I mean the selection stored in SharedPreferences
, that is selectedDaysValue
in .setMultiChoiceItems
. Suppose, these are the selected days when the dialog pops up:
Mon, Tue, Wed, Thu, Fri
Now, I change the selection as:
Mon, Tue
But, when I rotate the phone, the selection sets back to default:
Mon, Tue, Wed, Thu, Fri
How can I retain my selection on orientation change? Because in some apps I have seen, the Dialog selection remains same on rotation.
Android系统将自动恢复您的片段状态,而状态更改后的片段实际上并没有被破坏,而只是重新创建了它的视图,因此片段变量内的任何值都将保持原样,您要做的就是重新分配变量值对您的看法有价值,这是参考链接https://inthecheesefactory.com/blog/fragment-state-saving-best-practices/en
Well, this is the final solution I have made by making changes in the DialogFragment
code only:
Changing the scope of data to be stored:
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
return activity.let {
val selectedDaysValue = BooleanArray(7) { _ -> false }
val selectedDaysIndex = ArrayList<Int>()
to:
private var selectedDaysValue = BooleanArray(7) { _ -> false }
private var selectedDaysIndex = ArrayList<Int>()
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
return activity.let {
Storing the data:
override fun onSaveInstanceState(outState: Bundle) {
outState.putBooleanArray("selected_days_value", this.selectedDaysValue)
outState.putIntegerArrayList("selected_days_index", this.selectedDaysIndex)
}
And where I read the data as:
val prefs = it!!.getSharedPreferences(getString(R.string.shared_prefs_settings), Context.MODE_PRIVATE)
val selectedDaysString = prefs.getString("enabled_days", getString(R.string.default_enabled_days))
val selectedDays = selectedDaysString!!.split(", ")
for (day in selectedDays) {
selectedDaysValue[daysToIndexMap.getValue(day)] = true
selectedDaysIndex.add(daysToIndexMap.getValue(day))
}
to read from saved state as:
val prefs = activity!!.getSharedPreferences(getString(R.string.shared_prefs_settings), Context.MODE_PRIVATE)
if (savedInstanceState == null) {
val selectedDaysString = prefs.getString("enabled_days", getString(R.string.default_enabled_days))
val selectedDays = selectedDaysString!!.split(", ")
for (day in selectedDays) {
selectedDaysValue[daysToIndexMap.getValue(day)] = true
selectedDaysIndex.add(daysToIndexMap.getValue(day))
}
} else {
with(savedInstanceState) {
selectedDaysValue = getBooleanArray("selected_days_value")!!
selectedDaysIndex = getIntegerArrayList("selected_days_index")!!
}
}
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