如何将日期选择器活动添加到 android studio (kotlin) 中的片段

Question

我是 Android Studio 的新手，不确定它是如何工作的。我希望能够从片段中的日期选择器中选择一个日期，但不确定如何执行此操作。

我的主要活动包含到所有 4 个片段的底部导航

class MainActivity : AppCompatActivity() {

private val mOnNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener {item ->
    when(item.itemId){
        R.id.navigation_home -> {
            println("home pressed")
            replaceFragment(HomeFragment())
            return@OnNavigationItemSelectedListener true
        }
        R.id.navigation_social -> {
            println("social pressed")
            replaceFragment(SocialFragment())
            return@OnNavigationItemSelectedListener true
        }
        R.id.navigation_calendar -> {
            println("calendar pressed")
            replaceFragment(CalendarFragment())
            return@OnNavigationItemSelectedListener true
        }
        R.id.navigation_account -> {
            println("account pressed")
            replaceFragment(AccountFragment())
            return@OnNavigationItemSelectedListener true
        }
    }
    false
}

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

    bottomNavigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener)
    replaceFragment(HomeFragment())
}

private fun replaceFragment(fragment: Fragment){
    val fragmentTransaction = supportFragmentManager.beginTransaction()
    fragmentTransaction.replace(R.id.fragmentContainer, fragment)
    fragmentTransaction.commit()
}

在日历片段中，我创建了一个 DatePicker，如下所示：

<DatePicker
            android:id="@+id/Date_Picker"
            android:datePickerMode="calendar"
            android:layout_width="wrap_content"
            android:layout_height="400dp"
            android:background="@drawable/curved_frame"
            android:headerBackground="#FFFFFF"
            android:translationY="-80dp"></DatePicker>

我希望能够从日历中选择一个日期，但我不知道将这段代码放在哪里。我有以下代码用于选择日期，但不知道放在哪里：

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

    val datePicker = findViewById<DatePicker>(R.id.Date_Picker)
    val today = Calendar.getInstance()
    datePicker.init(today.get(Calendar.YEAR), today.get(Calendar.MONTH), today.get(Calendar.DAY_OF_MONTH))

    { view, year, month, day ->
        val month = month + 1
        val msg = "You selected: $day/$month/$year"
        Toast.makeText(this@fragment_calendar, msg, Toast.LENGTH_SHORT).show()
    }
}

我应该创建一个新活动并调用日历片段还是应该将此代码放在日历片段中？ 谢谢

我已经添加了下面的代码，但是当我点击我的日期选择器上的一个日期时它仍然没有做任何事情。

override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    val datePicker = view?.findViewById<DatePicker>(R.id.Date_Picker)
    val today = Calendar.getInstance()
    println(today)
    datePicker?.init(today.get(Calendar.YEAR), today.get(Calendar.MONTH), today.get(Calendar.DAY_OF_MONTH), object : DatePicker.OnDateChangedListener{
        override fun onDateChanged(
            view: DatePicker?,
            year: Int,
            monthOfYear: Int,
            dayOfMonth: Int
            ) {
                print(dayOfMonth)
            }
        })
    }

    // Inflate the layout for this fragment
    return inflater.inflate(R.layout.fragment_calendar, container, false)
}

Answer 1

您可以在初始化它的同一fragment/Activity 中使用onDateChangeListener。您可以在 onCreate 中添加以下代码：

 datePicker.init(today.get(Calendar.YEAR), today.get(Calendar.MONTH), today.get(Calendar.DAY_OF_MONTH), object : DatePicker.OnDateChangedListener{
            override fun onDateChanged(
                view: DatePicker?,
                year: Int,
                monthOfYear: Int,
                dayOfMonth: Int
            ) {
                //Set the date here
                Log.d("DATE", "Date Listener called")
            }

        })

希望这会有所帮助。