如何使设置 TextView.text 在 Android 应用程序（Kotlin）中持久化

Question

我目前正在尝试让 TextView 显示我的 TimePicker 返回的任何日期。它可以工作，但是如果我进入另一个片段并返回，重新启动应用程序等，文本将恢复为我设置的默认值。有谁知道我怎样才能使我设置的文本持久化？这是我正在使用的代码。

view.timeButton.setOnClickListener {
            val cal = Calendar.getInstance()
            val timeSetListener = TimePickerDialog.OnTimeSetListener { timePicker, hour, minute ->
                cal.set(Calendar.HOUR_OF_DAY, hour)
                cal.set(Calendar.MINUTE, minute)

                alarmText.text = ("Texts at " + SimpleDateFormat("HH:mm").format(cal.time))
            }
            TimePickerDialog(
                context,
                timeSetListener,
                cal.get(Calendar.HOUR_OF_DAY),
                cal.get(Calendar.MINUTE),
                false
            ).show()
        }

Answer 1

你可以使用SharedPreference永久保存

view.timeButton.setOnClickListener {
            val cal = Calendar.getInstance()
            val timeSetListener = TimePickerDialog.OnTimeSetListener { timePicker, hour, minute ->
                cal.set(Calendar.HOUR_OF_DAY, hour)
                cal.set(Calendar.MINUTE, minute)

                val simpleDateFormat = SimpleDateFormat("HH:mm")
                val date = simpleDateFormat.format(cal.time)
                alarmText.text = ("Texts at " + date)

                val preferences: SharedPreferences = PreferenceManager.getDefaultSharedPreferences(this)
                preferences.edit().putString("mydate", date).apply();
                
            }
            TimePickerDialog(
                context,
                timeSetListener,
                cal.get(Calendar.HOUR_OF_DAY),
                cal.get(Calendar.MINUTE),
                false
            ).show()
        }

并在您应用的onCreate 中检索存储的值

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
        try {
            val preferences: SharedPreferences = PreferenceManager.getDefaultSharedPreferences(this)
            val simpleDateFormat = SimpleDateFormat("HH:mm")
            val date: Date = simpleDateFormat.parse(preferences.getString("mydate", ""))
            alarmText.text = ("Texts at " + date)
        }
        catch (e: ParseException) {
        }
    }