如何在 Kotlin 中使用 DatePickerDialog？

Question

在 Java 中，可以使用 DatePickerDialog，例如：

final Calendar c = Calendar.getInstance();
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH);
int day = c.get(Calendar.DAY_OF_MONTH);


DatePickerDialog dpd = new DatePickerDialog(getActivity(),new DatePickerDialog.OnDateSetListener()
{
   @Override
   public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth)
  {
      // Display Selected date in textbox
      lblDate.setText(""+ dayOfMonth+" "+MONTHS[monthOfYear] + ", " + year);
  }
}, year, month,day);
dpd.show();

Kotlin 的 DatePickerDialog 使用起来怎么样？

Answer 1

看起来像这样：

val c = Calendar.getInstance()
val year = c.get(Calendar.YEAR)
val month = c.get(Calendar.MONTH)
val day = c.get(Calendar.DAY_OF_MONTH)


val dpd = DatePickerDialog(activity, DatePickerDialog.OnDateSetListener { view, year, monthOfYear, dayOfMonth ->

    // Display Selected date in textbox
    lblDate.setText("" + dayOfMonth + " " + MONTHS[monthOfYear] + ", " + year)

}, year, month, day)

dpd.show()

这是通过简单地将代码复制并粘贴到 android studio 中的 kotlin 文件中完成的。我强烈推荐使用它。

Answer 2

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val textView: TextView  = findViewById(R.id.textView_date)
        textView.text = SimpleDateFormat("dd.MM.yyyy").format(System.currentTimeMillis())

        var cal = Calendar.getInstance()

        val dateSetListener = DatePickerDialog.OnDateSetListener { view, year, monthOfYear, dayOfMonth ->
            cal.set(Calendar.YEAR, year)
            cal.set(Calendar.MONTH, monthOfYear)
            cal.set(Calendar.DAY_OF_MONTH, dayOfMonth)

            val myFormat = "dd.MM.yyyy" // mention the format you need
            val sdf = SimpleDateFormat(myFormat, Locale.US)
            textView.text = sdf.format(cal.time)

        }

        textView.setOnClickListener {
            DatePickerDialog(this@MainActivity, dateSetListener,
                    cal.get(Calendar.YEAR),
                    cal.get(Calendar.MONTH),
                    cal.get(Calendar.DAY_OF_MONTH)).show()
        }
    }
}

Answer 3

Kotlin Anko Android 示例：

alert {

    isCancelable = false

    lateinit var datePicker: DatePicker

    customView {
        verticalLayout {
            datePicker = datePicker {
                maxDate = System.currentTimeMillis()
            }
        }
    }

    yesButton {
        val parsedDate = "${datePicker.dayOfMonth}/${datePicker.month + 1}/${datePicker.year}"
    }

    noButton { }

}.show()

Answer 4

在点击按钮时使用显示日期选择器

   val cal = Calendar.getInstance()
    val y = cal.get(Calendar.YEAR)
    val m = cal.get(Calendar.MONTH)
    val d = cal.get(Calendar.DAY_OF_MONTH)


    val datepickerdialog:DatePickerDialog = DatePickerDialog(activity, DatePickerDialog.OnDateSetListener { view, year, monthOfYear, dayOfMonth ->

    // Display Selected date in textbox
    lblDate.setText("" + dayOfMonth + " " + MONTHS[monthOfYear] + ", " + year)
        }, y, m, d)

    datepickerdialog.show()

这用于按钮点击时的显示时间选择器

textView54.setOnClickListener {
                val c:Calendar= Calendar.getInstance()
                val hh=c.get(Calendar.HOUR_OF_DAY)
                val mm=c.get(Calendar.MINUTE)
                val timePickerDialog:TimePickerDialog=TimePickerDialog(this@VendorRegistration,TimePickerDialog.OnTimeSetListener { view, hourOfDay, minute ->
                    textView54.setText( ""+hourOfDay + ":" + minute);
                },hh,mm,true)
                timePickerDialog.show()

Answer 5

如果您想使用协程来桥接回调模式，您可以使用像这样的解决方案。请注意，我在这里同时使用了日期和时间选择器，但如果不需要，您可以轻松删除 TimePicker 逻辑。

suspend fun Context.openDateTimePicker(calendar: Calendar = Calendar.getInstance()): Instant =
    suspendCoroutine { continuation ->
        val dateSetListener = DatePickerDialog.OnDateSetListener { _, year, month, day ->
            val timeSetListener = TimePickerDialog.OnTimeSetListener { _, hour, minute ->
                calendar
                    .apply { set(year, month, day, hour, minute) }
                    .run { Instant.ofEpochMilli(timeInMillis).truncatedTo(ChronoUnit.MINUTES) }
                    .let { continuation.resume(it) }
            }

            TimePickerDialog(
                this,
                timeSetListener,
                calendar.get(Calendar.HOUR_OF_DAY),
                calendar.get(Calendar.MINUTE),
                DateFormat.is24HourFormat(this)
            ).show()
        }

        DatePickerDialog(
            this,
            dateSetListener,
            calendar.get(Calendar.YEAR),
            calendar.get(Calendar.MONTH),
            calendar.get(Calendar.DAY_OF_MONTH)
        ).show()
    }

Answer 6

我使用 Kotlin，所以我想要 Kotlin 解决方案而不是 Java 解决方案。

所以首先我仔细查看了@FrostRocket 的解决方案作为起点。 @FrostRocket 的解决方案对我很有用。

就我而言，我忽略了所有 Kotlin 世界。以及我只能使用 OffsetDateTime 而不能使用日历 class。另外，我之前从来没有用过coroutine，所以不得不去阅读和研究Kotlin中的coroutines。如果您在我的代码中发现一些理论或实践错误，请告诉我。

首先在我的扩展包中添加一个新文件：ContextExtention.kt

import android.app.DatePickerDialog
import android.app.TimePickerDialog
import android.content.Context
import android.text.format.DateFormat
import java.time.OffsetDateTime
import kotlin.coroutines.resume
import kotlin.coroutines.suspendCoroutine

    suspend fun Context.openDateTimePicker(offsetDateTime: OffsetDateTime = OffsetDateTime.now()): OffsetDateTime =
suspendCoroutine { continuation ->
    val dateSetListener = DatePickerDialog.OnDateSetListener { _, year, month, day ->
        //month (0-11 for compatibility with Calendar#MONTH)
        // day of the month (1-31, depending on month)
        val timeSetListener = TimePickerDialog.OnTimeSetListener { _, hour, minute ->
            offsetDateTime.let {
            val newOffsetDateTime =
                offsetDateTime.withHour(hour).withMinute(minute).withYear(year)
                    //withMonth from 1 (January) to 12 (December)
                    //so I have to adapt it.
                    .withMonth((month+1))
                    //withDayOfMonth from 1 to 28-31
                    //so no need adaptation
                    .withDayOfMonth(day)
                    continuation.resume(newOffsetDateTime)
                }
        }

        TimePickerDialog(
            this,
            timeSetListener,
            offsetDateTime.hour,
            offsetDateTime.minute,
            DateFormat.is24HourFormat(this)
        ).show()
    }

    //the initially selected month (0-11 for compatibility with Calendar#MONTH)
    //when offsetDateTime.monthValue from 1 (January) to 12 (December)
    //so I have to adapt it.
    DatePickerDialog(
        this,
        dateSetListener,
        offsetDateTime.year,
        (offsetDateTime.monthValue-1),
        offsetDateTime.dayOfMonth
    ).show()
}

那么我怎样才能运行暂停功能呢？所以你运行 kotlinx.coroutines.Job 中的一个协程，CoroutineScope 让我想起了 iPhone 编程中的 Grand Central Dispatcher 你有一个服务质量列表。

在这种情况下，如果您想使用 UI 线程，您必须使用：Dispatchers.Main 或 Dispatchers.Main。如果您需要更好的服务，请立即使用。

import android.widget.TextView
import androidx.lifecycle.Observer
// the R import here 
// the openDateTimePicker import here 
// the TimeHelper (is text formatter) import here 
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlinx.coroutines.launch


class FooFragment : Fragment() {

private lateinit var viewModel: FooViewModel

private lateinit var dateButton: Button
private lateinit var dateText: TextView
private var datePickerJob : Job? = null
val uiScope = CoroutineScope(Dispatchers.Main)

override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    val root =
     inflater.inflate(R.layout.foo_fragment, container, false)
    dateButton = root.findViewById(R.id.textButtonChangeDate)
    dateText = root.findViewById(R.id.textViewWeighingDateValue)
    viewModel = ViewModelProvider(this).get(FooViewModel::class.java)
    return root
}

override fun onActivityCreated(savedInstanceState: Bundle?) {
    super.onActivityCreated(savedInstanceState)
    viewModel.dateTimeText.observe(viewLifecycleOwner, Observer {
        dateText.text = it.format(TimeHelper.formatter)
//the call to setNewDateTime will refresh this value
    })
}

override fun onStart() {
    super.onStart()
    dateButton.setOnClickListener {
        datePickerJob = uiScope.launch {
            viewModel.setNewDateTime(context?.openDateTimePicker())
//setNewDateTime is a setValue in a MutableLiveData
        }
    }

}

override fun onStop() {
    super.onStop()
    dateButton.setOnClickListener(null)
    datePickerJob?.cancel()
}

}

Answer 7

dateColumn.setOnClickListener {
        val c = Calendar.getInstance()
        val yr = c.get(Calendar.YEAR)
        val month = c.get(Calendar.MONTH)
        val day = c.get(Calendar.DAY_OF_MONTH)
        val display = DatePickerDialog(context as BaseActivity, DatePickerDialog.OnDateSetListener {
                view, year, monthOfYear, dayOfMonth ->
            var monthInput = (monthOfYear + 1).toString()
            if (monthInput.toInt() == 1) {
                monthInput = "Jan"
            } else if (monthInput.toInt() == 2) {
                monthInput = "Feb"
            } else if (monthInput.toInt() == 3) {
                monthInput = "March"
            } else if (monthInput.toInt() == 4) {
                monthInput = "April"
            } else if (monthInput.toInt() == 5) {
                monthInput = "May"
            } else if (monthInput.toInt() == 6) {
                monthInput = "June"
            } else if (monthInput.toInt() == 7) {
                monthInput = "July"
            } else if (monthInput.toInt() == 8) {
                monthInput = "Aug"
            } else if (monthInput.toInt() == 9) {
                monthInput = "Sept"
            } else if (monthInput.toInt() == 10) {
                monthInput = "Oct"
            } else if (monthInput.toInt() == 11) {
                monthInput = "Nov"
            } else if (monthInput.toInt() == 12) {
                monthInput = "Dec"
            }
            dateColumn.text = ("$dayOfMonth $monthInput, $year")
        }, yr, month, day)
        display.datePicker.minDate = System.currentTimeMillis()
        display.show()
    }

如何在 Kotlin 中使用 DatePickerDialog？

How to use DatePickerDialog in Kotlin?

kotlin

datepickerdialog