Question

我有一个对话框来选择一周中的一天以上，如下所示：

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()
        }
    }
}

我在活动中以这种方式调用此对话框：

findViewById<LinearLayout>(R.id.settings_enabled_days)
    .setOnClickListener {
        DialogSettingsEnabledDays().show(this.supportFragmentManager, null)
}

我的问题是我选择的天数在轮换时重置为默认值。默认情况下，我的意思是存储在SharedPreferences中的选择，即selectedDaysValue中的.setMultiChoiceItems。假设这些是弹出对话框的选定日期：

Mon, Tue, Wed, Thu, Fri

现在，我将选择更改为：

Mon, Tue

但是，当我旋转手机时，选择项会恢复为默认设置：

Mon, Tue, Wed, Thu, Fri

如何保留更改方向的选择？因为在我看到的某些应用中，对话框选择在旋转时保持不变。

Answer 1

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，而是仅重新创建其视图，因此片段变量内的值将保持原样，您所要做的重新分配变量值到您的视图，这是参考链接https://inthecheesefactory.com/blog/fragment-state-saving-best-practices/en

Answer 2

好吧，这是我仅通过更改DialogFragment代码而做出的最终解决方案：

更改要存储的数据范围：

override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
    return activity.let {
        val selectedDaysValue = BooleanArray(7) { _ -> false }
        val selectedDaysIndex = ArrayList<Int>()

收件人：

private var selectedDaysValue = BooleanArray(7) { _ -> false }
private var selectedDaysIndex = ArrayList<Int>()

override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
    return activity.let {

存储数据：

override fun onSaveInstanceState(outState: Bundle) {
    outState.putBooleanArray("selected_days_value", this.selectedDaysValue)
    outState.putIntegerArrayList("selected_days_index", this.selectedDaysIndex)
}

我在哪里读取数据为：

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))
}

从保存状态读取为：

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")!!
    }
}

如何在旋转的Android中的多选对话框中保留选择？

2 个答案: