사진찍은 날짜 관련 QA

app/src/main/java/com/teampophory/pophory/feature/home/photo/AddPhotoActivity.kt

@@ -1,31 +1,87 @@
 package com.teampophory.pophory.feature.home.photo
 
 import android.os.Bundle
+import androidx.activity.viewModels
+import androidx.lifecycle.flowWithLifecycle
+import androidx.lifecycle.lifecycleScope
 import com.google.android.material.datepicker.CalendarConstraints
+import com.google.android.material.datepicker.DateValidatorPointBackward
 import com.google.android.material.datepicker.MaterialDatePicker
 import com.teampophory.pophory.R
 import com.teampophory.pophory.common.activity.BindingActivity
 import com.teampophory.pophory.common.time.systemNow
 import com.teampophory.pophory.databinding.ActivityAddPhotoBinding
 import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 import kotlinx.datetime.Instant
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+import java.util.TimeZone
 
 @AndroidEntryPoint
 class AddPhotoActivity : BindingActivity<ActivityAddPhotoBinding>(R.layout.activity_add_photo) {
+    private val viewModel: AddPhotoViewModel by viewModels()
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
+        initView()
+        subscribeEvent()
+        collectState()
+    }
+
+    private fun initView() {
         binding.layoutDate.setOnClickListener {
-            MaterialDatePicker.Builder
-                .datePicker()
-                .setTheme(R.style.ThemeOverlay_Pophory_MaterialCalendar)
-                .setInputMode(MaterialDatePicker.INPUT_MODE_CALENDAR)
-                .setCalendarConstraints(
-                    CalendarConstraints.Builder()
-                        .setEnd(Instant.systemNow().toEpochMilliseconds())
-                        .build()
-                )
-                .build()
-                .show(supportFragmentManager, "datePicker")
+            viewModel.onCreatedAtPressed()
         }
+        binding.layoutStudio.setOnClickListener {
+            viewModel.onStudioPressed()
+        }
+    }
+
+    private fun subscribeEvent() {
+        viewModel.event
+            .flowWithLifecycle(lifecycle)
+            .onEach {
+                when (it) {
+                    AddPhotoEvent.DATE -> {
+                        val currentCreatedAt = viewModel.createdAt.value
+                        val picker = MaterialDatePicker.Builder
+                            .datePicker()
+                            .setTheme(R.style.ThemeOverlay_Pophory_MaterialCalendar)
+                            .setInputMode(MaterialDatePicker.INPUT_MODE_CALENDAR)
+                            .setCalendarConstraints(
+                                CalendarConstraints.Builder()
+                                    .setValidator(
+                                        DateValidatorPointBackward.now()
+                                    )
+                                    .setEnd(Instant.systemNow().toEpochMilliseconds()).build()
+                            )
+                            .setSelection(
+                                currentCreatedAt + TimeZone.getDefault().getOffset(currentCreatedAt)
+                            )
+                            .build()
+                        picker.show(supportFragmentManager, "datePicker")
+                        picker.addOnPositiveButtonClickListener(viewModel::onUpdateCreateAt)
+                    }
+
+                    AddPhotoEvent.STUDIO -> {
+                        // TODO BottomSheet 회의
+                    }
+                }
+            }.launchIn(lifecycleScope)
+    }
+
+    private fun collectState() {
+        viewModel.createdAt
+            .flowWithLifecycle(lifecycle)
+            .onEach {
+                binding.txtDate.text =
+                    SimpleDateFormat(
+                        "yyyy.MM.dd(EEEEE)",
+                        Locale.getDefault()
+                    ).format(Date(it))
+            }.launchIn(lifecycleScope)
     }
 }

app/src/main/java/com/teampophory/pophory/feature/home/photo/AddPhotoViewModel.kt

@@ -0,0 +1,43 @@
+package com.teampophory.pophory.feature.home.photo
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.teampophory.pophory.common.time.systemNow
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asSharedFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import kotlinx.datetime.Instant
+import javax.inject.Inject
+
+enum class AddPhotoEvent {
+    DATE,
+    STUDIO;
+}
+
+@HiltViewModel
+class AddPhotoViewModel @Inject constructor() : ViewModel() {
+    private val _createdAt = MutableStateFlow(Instant.systemNow().toEpochMilliseconds())
+    val createdAt = _createdAt.asStateFlow()
+    private var studio: String? = null
+    private val _event = MutableSharedFlow<AddPhotoEvent>()
+    val event = _event.asSharedFlow()
+
+    fun onCreatedAtPressed() {
+        viewModelScope.launch {
+            _event.emit(AddPhotoEvent.DATE)
+        }
+    }
+
+    fun onUpdateCreateAt(new: Long) {
+        _createdAt.value = new
+    }
+
+    fun onStudioPressed() {
+        viewModelScope.launch {
+            _event.emit(AddPhotoEvent.STUDIO)
+        }
+    }
+}

core/common/src/main/java/com/teampophory/pophory/common/time/TimeExt.kt

@@ -1,5 +1,7 @@
 package com.teampophory.pophory.common.time
 
+import android.content.Context
+import android.text.format.DateUtils
 import kotlinx.datetime.Clock
 import kotlinx.datetime.Instant
 import kotlinx.datetime.LocalDate
@@ -8,4 +10,21 @@ import kotlinx.datetime.toLocalDateTime
 
 fun Instant.Companion.systemNow(): Instant = Clock.System.now()
 
-fun Instant.toDefaultLocalDate(): LocalDate = toLocalDateTime(TimeZone.currentSystemDefault()).date
+fun Instant.toDefaultLocalDate(): LocalDate = toLocalDateTime(TimeZone.currentSystemDefault()).date
+
+fun Long.formatDate(context: Context): String = DateUtils.formatDateTime(
+    context,
+    this,
+    DateUtils.FORMAT_SHOW_YEAR or DateUtils.FORMAT_SHOW_DATE
+)
+
+fun Instant.formatDate(context: Context): String = toEpochMilliseconds().formatDate(context)
+
+fun Long.formatNumericDate(context: Context): String = DateUtils.formatDateTime(
+    context,
+    this,
+    DateUtils.FORMAT_SHOW_YEAR or DateUtils.FORMAT_SHOW_DATE or DateUtils.FORMAT_NUMERIC_DATE
+)
+
+fun Instant.formatNumericDate(context: Context): String =
+    toEpochMilliseconds().formatNumericDate(context)