Question

下面的代码运行良好，我试图确定一旦选择日期后如何计算总天数。非常感谢。

我要解决的问题：选择休假开始日期-日期选择器-这部分效果很好选择假期结束日期-日期选择器-这部分效果很好 总天数=计算结束日期-开始日期-我不知道如何进行计算 总共10天

这是我的代码

class VacationActivity : AppCompatActivity() {

    private var selectedYear = 0
    private var selectedMonth = 0
    private var selectedDay = 0

    @RequiresApi(Build.VERSION_CODES.O)
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_vacation)


        // get view
        val tvDate = findViewById<TextView>(R.id.from_date_view)
        tvDate.setOnClickListener {

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


            if (tvDate.text.isNotEmpty()) {
                this.selectedYear
                this.selectedMonth
                this.selectedDay
            }

            var listener = DatePickerDialog.OnDateSetListener { view, selectedYear, selectedMonth, selectedDay ->
                this.selectedYear = selectedYear
                this.selectedMonth = selectedMonth
                this.selectedDay = selectedDay

                tvDate.text = "${selectedMonth + 1}/$selectedDay/$selectedYear"

            }
            val datePicker = DatePickerDialog(this, listener, year, month, day)
            datePicker.show()
        }


        val tvDate2 = findViewById<TextView>(R.id.to_date_view)
        tvDate2.setOnClickListener {

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


            if (tvDate2.text.isNotEmpty()) {
                this.selectedYear
                this.selectedMonth
                this.selectedDay
            }

            var listener = DatePickerDialog.OnDateSetListener { view, selectedYear, selectedMonth, selectedDay ->
                this.selectedYear = selectedYear
                this.selectedMonth = selectedMonth
                this.selectedDay = selectedDay

                tvDate2.text = "${selectedMonth + 1}/$selectedDay/$selectedYear"
            }

            val datePicker = DatePickerDialog(this, listener, year, month, day)
            datePicker.show()


        }


            }
        }

Answer 1

您可以使用以下功能：

fun getLocalDateFromString(d: String, format: String): LocalDate {
    return LocalDate.parse(d, DateTimeFormatter.ofPattern(format))
}

它从以LocalDate格式设置的字符串d返回format。

fun getDaysDif(fromDate: LocalDate, toDate: LocalDate): Long {
    return ChronoUnit.DAYS.between(fromDate, toDate)
}

它返回两个日期（LocalDate）之间的天数差异

因此您可以这样做：

val days = getDaysDif(
        getLocalDateFromString(tvDate1.text, "MM/dd/yyyy"),
        getLocalDateFromString(tvDate2.text, "MM/dd/yyyy"))

以上代码适用于API级别26及更高版本。

对于较低版本，请使用此：

val format = SimpleDateFormat("MM/dd/yyyy")
val days = TimeUnit.DAYS.convert(
    format.parse(tvDate2.text).getTime() - 
    format.parse(tvDate1.text).getTime(), 
    TimeUnit.MILLISECONDS)

在科特林计算日期

1 个答案: