如何解决如何将ViewModel添加到使用ViewPager和Tablayout的项目中？
您好，我是Android开发的新手，所以这个问题可能对您来说很奇怪。
我有一个名为 IdentityCardInfo 的类，该类具有变量。我在 InfoFragment 中得到了这个变量。
在InfoFragment中，我想在 ResultsFragment 中显示这些变量，该变量具有3个带有TabLayout的标签。
我想使用 viewmodel 将数据传递到布局，但我不知道该如何使用，但搜索却卡住了。
这是IdentityCardInfo类的代码：
class IdentityCardInfo {
companion object AppConstant{
const val serieNo ="67G74444"
const val validDate = "01/01/2022"
const val dateOfBirth = "10/08/1998"
const val fullName = "Muhittin KAYA"
const val identityNo: Long = 11111111111
const val gender = "MALE"
const val nationality = "TUR"
}
}
以下是InfoFragment的代码：
class InfoFragment : BaseFragment() {
lateinit var navController: NavController
companion object {
private const val TAG = "Info Fragment"
}
override fun onCreateView(
inflater: LayoutInflater,container: ViewGroup?,savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_info,container,false)
}
override fun onViewCreated(view: View,savedInstanceState: Bundle?) {
super.onViewCreated(view,savedInstanceState)
navController = Navigation.findNavController(view)
button_info_idcard.setonClickListener {
//start OcrActivity
val intent = Intent(activity,OcrActivity::class.java)
startActivityForResult(intent,101)
}
imagebutton_info_settings.setonClickListener {
navController.navigate(R.id.action_infoFragment_to_settingsFragment)
}
}
override fun onActivityResult(requestCode: Int,resultCode: Int,data: Intent?) {
super.onActivityResult(requestCode,resultCode,data)
Log.i("Muhittin","onActivityResult()")
if (requestCode == 101) {
val message = data?.getStringExtra("TEST_TEXT")
Toast.makeText(context,message,Toast.LENGTH_SHORT).show()
val serieNo = IdentityCardInfo.serieNo
val validDate = IdentityCardInfo.validDate
val dateOfBirth = IdentityCardInfo.dateOfBirth
val fullname = IdentityCardInfo.fullName
val gender = IdentityCardInfo.gender
val identityNo = IdentityCardInfo.identityNo
val nationality = IdentityCardInfo.nationality
val bundle = bundleOf(
"TEST_TEXT" to message,"SERIE_NO" to serieNo,"VALID_DATE" to validDate,"dob" to dateOfBirth,"FULL_NAME" to fullname,"GENDER" to gender,"IDENTITY_NO" to identityNo,"NATIONALITY" to nationality
)
navController.navigate(
R.id.action_infoFragment_to_detailFragment,bundle
)
}
}
}
这是针对ResultsFragment的：（我不添加制表符代码和viewpager代码）
class ResultsFragment : Fragment() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
retainInstance = true
}
override fun onCreateView(
inflater: LayoutInflater,savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_results,false)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
val tabLayout: TabLayout = requireView().findViewById(R.id.tabLayout_results)
tabLayout.tabGravity = TabLayout.GraviTY_FILL
val tabTitles = arrayOf(
resources.getString(R.string.result_tab1_name),resources.getString(R.string.result_tab2_name),resources.getString(R.string.result_tab3_name)
)
val viewPager: ViewPager = requireView().findViewById(R.id.viewpager_results)
viewPager.offscreenPageLimit = 3
val adapter = PagerAdapter(fragmentManager,tabTitles)
viewPager.adapter = adapter
tabLayout.setupWithViewPager(viewPager)
}
}
解决方法
如果您要使用<div style="height:100px;background-color:red">text</div>在同一活动的片段之间进行数据传输，请here's the Android documentation about it。它允许片段访问共享对象而无需彼此了解，或通过活动进行通信（使用一堆代码来实现该通信）
您基本上会执行以下操作：
<link href='https://fonts.googleapis.com/css?family=PT Serif Caption' rel='stylesheet'>
然后，每个片段将通过执行以下操作来获取同一ViewModel实例的副本：
ViewModel，然后// create a ViewModel that holds the data you want to share
class IdentityCardViewModel : ViewModel() {
val identityInfo = MutableLiveData<IdentityCardInfo>()
fun setInfo(info: IdentityCardInfo) {
identityInfo.value = info
}
}
可以使用// Get a reference to the IdentityCardViewModel created and held by the activity
private val model: IdentityCardViewModel by activityViewModels()
设置数据。 InfoFragment可以观察此数据并在看到新值时执行一些操作：
model.setInfo(yourIdentityCardInfo)@muhittin kaya请参阅下面的代码来解决您的问题
InfoFragment
class InfoFragment : BaseFragment() {
lateinit var navController: NavController
// Initialize your variable
lateinit var infoFragmentInterface: InfoFragmentDataInterface
// If you get initialization exception then uncomment below line and comment above line
//private var infoFragmentInterface: InfoFragmentDataInterface? = null
companion object {
private const val TAG = "Info Fragment"
}
override fun onCreateView(
inflater: LayoutInflater,container: ViewGroup?,savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_info,container,false)
}
override fun onViewCreated(view: View,savedInstanceState: Bundle?) {
super.onViewCreated(view,savedInstanceState)
navController = Navigation.findNavController(view)
button_info_idcard.setOnClickListener {
//start OcrActivity
val intent = Intent(activity,OcrActivity::class.java)
startActivityForResult(intent,101)
}
imagebutton_info_settings.setOnClickListener {
navController.navigate(R.id.action_infoFragment_to_settingsFragment)
}
}
override fun onActivityResult(requestCode: Int,resultCode: Int,data: Intent?) {
super.onActivityResult(requestCode,resultCode,data)
Log.i("Muhittin","onActivityResult()")
if (requestCode == 101) {
val message = data?.getStringExtra("TEST_TEXT")
Toast.makeText(context,message,Toast.LENGTH_SHORT).show()
val serieNo = IdentityCardInfo.serieNo
val validDate = IdentityCardInfo.validDate
val dateOfBirth = IdentityCardInfo.dateOfBirth
val fullname = IdentityCardInfo.fullName
val gender = IdentityCardInfo.gender
val identityNo = IdentityCardInfo.identityNo
val nationality = IdentityCardInfo.nationality
val bundle = bundleOf(
"TEST_TEXT" to message,"SERIE_NO" to serieNo,"VALID_DATE" to validDate,"DOB" to dateOfBirth,"FULL_NAME" to fullname,"GENDER" to gender,"IDENTITY_NO" to identityNo,"NATIONALITY" to nationality
)
//Add This line for passing your data
//You can also pass string data here
infoFragmentInterface.getInfoFragmentData(bundle)
navController.navigate(
R.id.action_infoFragment_to_detailFragment,bundle
)
}
}
}
// Create this interface to pass your data
interface InfoFragmentDataInterface {
fun getInfoFragmentData(bundle: Any)
}
结果片段
class ResultsFragment : Fragment(),InfoFragmentDataInterface {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
retainInstance = true
}
override fun onCreateView(
inflater: LayoutInflater,savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_results,false)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
val tabLayout: TabLayout = requireView().findViewById(R.id.tabLayout_results)
tabLayout.tabGravity = TabLayout.GRAVITY_FILL
val tabTitles = arrayOf(
resources.getString(R.string.result_tab1_name),resources.getString(R.string.result_tab2_name),resources.getString(R.string.result_tab3_name)
)
val viewPager: ViewPager = requireView().findViewById(R.id.viewpager_results)
viewPager.offscreenPageLimit = 3
val adapter = PagerAdapter(fragmentManager,tabTitles)
viewPager.adapter = adapter
tabLayout.setupWithViewPager(viewPager)
}
override fun getInfoFragmentData(bundle: Any) {
// You'll get your Bundle data here.
}
}
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