我是android开发新手。通过big nerd ranch android 4e book学习这是一个例子,书中的方法被折旧了,那么我如何将日期数据发送到另一个片段
他们使用的是贬值的targetfragment技术,所以我现在被困在这个问题上
这是我的 datepickerfragment.kt
文件:
private const val ARG_DATE = "date"
private const val RESULT_DATE_KEY = "resultDate"
private const val ARG_REQUEST_CODE = "requestCode"
class DatePickerFragment : DialogFragment() {
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
val dateListener = DatePickerDialog.OnDateSetListener { _: DatePicker, year: Int, month: Int, day: Int ->
val resultDate: Date = GregorianCalendar(year, month, day).time
val result = Bundle().apply {
putSerializable(RESULT_DATE_KEY, resultDate)
}
val resultRequestCode = requireArguments().getString(ARG_REQUEST_CODE, "")
}
val date = arguments?.getSerializable(ARG_DATE) as Date
val calendar = Calendar.getInstance()
calendar.time = date
val initialYear = calendar.get(Calendar.YEAR)
val initialMonth = calendar.get(Calendar.MONTH)
val initialDay = calendar.get(Calendar.DAY_OF_MONTH)
return DatePickerDialog(
requireContext(),
dateListener,
initialYear,
initialMonth,
initialDay
)
}
interface Callbacks {
fun onDateSelected(date: Date)
}
companion object {
fun getSelectedDate(result: Bundle) = result.getSerializable(RESULT_DATE_KEY) as Date
fun newInstance(date: Date, requestCode: String): DatePickerFragment {
val args = Bundle().apply {
putSerializable(ARG_DATE, date)
putString(ARG_REQUEST_CODE, requestCode)
}
return DatePickerFragment().apply {
arguments = args
}
}
}
}
这是我的crimefragment.kt课程:
private const val ARG_CRIME_ID = "crime_id"
private const val TAG = "CrimeFragment"
private const val REQUEST_DATE = "DialogDate"
class CrimeFragment : Fragment(), DatePickerFragment.Callbacks, FragmentResultListener {
private lateinit var crime: Crime
private lateinit var titleField: EditText
private lateinit var dateButton: Button
private lateinit var solvedCheckBox: CheckBox
private val crimeDetailViewModel: CrimeDetailViewModel by lazy {
ViewModelProvider(this).get(CrimeDetailViewModel::class.java)
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
crime = Crime()
val crimeId: UUID = arguments?.getSerializable(ARG_CRIME_ID) as UUID
Log.d(TAG, "args bundle crime Id:$crimeId")
crimeDetailViewModel.loadCrime(crimeId)
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_crime, container, false)
titleField = view.findViewById(R.id.crime_title) as EditText
solvedCheckBox = view.findViewById(R.id.crime_solved1) as CheckBox
dateButton = view.findViewById(R.id.crime_date)
return view
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
crimeDetailViewModel.crimeLiveData.observe(
viewLifecycleOwner,
Observer { crime ->
crime?.let {
this.crime = crime
updateUI()
}
}
)
childFragmentManager.setFragmentResultListener(REQUEST_DATE, viewLifecycleOwner, this)
}
override fun onStart() {
super.onStart()
val titleWatcher = object : TextWatcher {
override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {
}
override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
crime.title = s.toString()
}
override fun afterTextChanged(s: Editable?) {
}
}
titleField.addTextChangedListener(titleWatcher)
dateButton.setOnClickListener {
DatePickerFragment
.newInstance(crime.date, REQUEST_DATE)
.show(childFragmentManager, REQUEST_DATE)
}
solvedCheckBox.apply {
setOnCheckedChangeListener { _, isChecked ->
crime.isSolved = isChecked
}
}
}
private fun updateUI() {
titleField.setText(crime.title)
dateButton.text = crime.date.toString()
solvedCheckBox.apply {
isChecked = crime.isSolved
jumpDrawablesToCurrentState()
}
}
companion object {
fun newInstance(crimeId: UUID): CrimeFragment {
val args = Bundle().apply {
putSerializable(ARG_CRIME_ID, crimeId)
}
return CrimeFragment().apply { arguments = args }
}
}
override fun onStop() {
super.onStop()
crimeDetailViewModel.saveCrime(crime)
}
override fun onDateSelected(date: Date) {
crime.date = date
}
override fun onFragmentResult(requestCode: String, result: Bundle) {
when (requestCode) {
REQUEST_DATE -> {
Log.d(TAG, "received result for $requestCode")
crime.date = DatePickerFragment.getSelectedDate(result)
updateUI()
}
}
}
}
3条答案
按热度按时间gojuced71#
您似乎正在使用片段结果api,这需要两个步骤。首先是你
setFragmentResultListener
在您希望接收结果的片段中(在您的案例中为crimefragment),在调用setFragmentResult
从产生结果的片段。你错过了第二步。要解决此问题,请更新OnDateSetListener
作为现在在
CrimeFragment
登记FragmentResultListener
作为现在更新
onFragmentResult
到除此之外,您还可以采取另一种方法,即使用共享
ViewModel
,因为这两个片段共享活动,所以您可以获得ViewModel
与活动相关的。获取crimefragment和datepickerfragment中的viewmodel作为
现在在
OnDateSetListener
属于DatePickerFragment
只需将日期存储在某个viewmodel属性中即可在此之后,您可以访问
crimeDetailViewModel.date
在…内CrimeFragment
chy5wohz2#
如果使用jetpack组件中的导航组件,则可以使用
getPreviousBackStackEntry()
要从选择器对话框中用选择器的结果填充启动器片段的捆绑包,然后当返回到启动器片段时,使用getCurrentBackStackEntry
.您可以参考此视频以获取示例
如果不使用导航组件,则可以使用作用域为活动的共享viewmodel。您将在两个片段中获得对该共享viewmodel的引用。然后,日期选择器将填充共享viewmodel中的某个字段,启动程序片段将在恢复时读取该字段。
vwkv1x7d3#
一种方法是使用事件、总线事件或rx。