I'm using a navigation drawer for my app. It functions well when I initially open the app. I can navigate from the Home Fragment to the Borrow Fragment using the navigation drawer. However, after several navigations, it stops working.
I have two fragments within the navigation drawer: Home Fragment and Borrow Fragment. The Home Fragment leads to the Book Info Fragment, which, in turn, leads to the Maps Fragment. The Maps Fragment eventually leads to the Borrow Fragment. The navigation happens using the navigation directions.
When I'm in the Borrow Fragment through this route, I can't navigate back to the Home Fragment using the navigation drawer. It only pops up to the Home Fragment. Any insights on what might be causing this issue?
activity_main_drawer.xml:
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:showIn="navigation_view">
<group android:checkableBehavior="single">
<item
android:id="@+id/nav_home"
android:icon="@drawable/home_icon"
android:title="@string/menu_home" />
<item
android:id="@+id/nav_borrow"
android:icon="@drawable/book_icon"
android:title="@string/menu_borrow" />
<item
android:id="@+id/nav_settings"
android:icon="@drawable/setting"
android:title="@string/menu_settings" />
</group>
</menu>
mobile_navigation.xml:
<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/mobile_navigation"
app:startDestination="@id/nav_home">
<fragment
android:id="@+id/nav_home"
android:name="com.example.bookradar.HomeFragment"
android:label="@string/menu_home"
tools:layout="@layout/fragment_home">
<action
android:id="@+id/action_nav_home_to_nav_book_info"
app:destination="@id/nav_book_info"
app:enterAnim="@anim/slide_in_right"
app:exitAnim="@anim/slide_out_left"
app:popEnterAnim="@anim/slide_in_left"
app:popExitAnim="@anim/slide_out_right"
/>
</fragment>
<fragment
android:id="@+id/nav_borrow"
android:name="com.example.bookradar.BorrowFragment"
android:label="BorrowFragment"
tools:layout="@layout/fragment_borrow">
<argument
android:name="item"
android:defaultValue="@null"
app:argType="com.example.bookradar.BookInfo"
app:nullable="true" />
</fragment>
<fragment
android:id="@+id/nav_maps"
android:name="com.example.bookradar.MapsFragment"
android:label="MapsFragment"
tools:layout="@layout/fragment_maps">
<action
android:id="@+id/action_nav_maps_to_nav_borrow"
app:destination="@id/nav_borrow" />
<argument
android:name="books"
app:argType="com.example.bookradar.BookInfo[]"/>
</fragment>
<fragment
android:id="@+id/nav_book_info"
android:name="com.example.bookradar.BookInfoFragment"
android:label="@string/nav_book_info"
tools:layout="@layout/fragment_book_info">
<argument
android:name="item"
android:defaultValue="@null"
app:argType="com.example.bookradar.model.BookModel"
app:nullable="true" />
<action
android:id="@+id/action_nav_book_info_to_nav_maps"
app:destination="@id/nav_maps" />
</fragment>
</navigation>
MainActivity.kt:
class MainActivity : AppCompatActivity() {
private lateinit var appBarConfiguration: AppBarConfiguration
private lateinit var binding: ActivityMainBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding.root)
setSupportActionBar(binding.appBarMain.toolbar)
/*binding.appBarMain.fab.setOnClickListener { view ->
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show()
}*/
val navHostFragment =
supportFragmentManager.findFragmentById(R.id.nav_host_fragment_content_main) as NavHostFragment
val navController = navHostFragment.navController
setSupportActionBar(binding.appBarMain.toolbar)
val drawerLayout: DrawerLayout = binding.drawerLayout
val navView: NavigationView = binding.navView
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
appBarConfiguration = AppBarConfiguration(
setOf(
R.id.nav_home, R.id.nav_borrow, R.id.nav_maps
), drawerLayout
)
setupActionBarWithNavController(navController, appBarConfiguration)
navView.setupWithNavController(navController)
}
override fun onCreateOptionsMenu(menu: Menu): Boolean {
// Inflate the menu; this adds items to the action bar if it is present.
menuInflater.inflate(R.menu.main, menu)
return true
}
override fun onSupportNavigateUp(): Boolean {
val navController = findNavController(R.id.nav_host_fragment_content_main)
return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
}
}
HomeFragment.kt:
class HomeFragment : Fragment() {
private lateinit var adapter: MyBookRecyclerViewAdapter
private lateinit var apiKey: String
private lateinit var binding: FragmentHomeBinding
private lateinit var recyclerView: RecyclerView
private lateinit var bookList: MutableList<BookModel>
var rootView: View? = null
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?
): View {
if (rootView != null) {
return rootView as View
}
binding = FragmentHomeBinding.inflate(inflater, container, false)
rootView = binding.root
apiKey = "KakaoAK " + BuildConfig.KAKAO_API
val searchBar = binding.searchBook
recyclerView = binding.listBook
bookList = mutableListOf<BookModel>()
adapter = MyBookRecyclerViewAdapter(bookList,
object : MyBookRecyclerViewAdapter.OnItemClickListener {
override fun onItemClick(item: BookModel) {
val action = HomeFragmentDirections.actionNavHomeToNavBookInfo(item)
findNavController().navigate(action)
}
})
recyclerView.layoutManager = LinearLayoutManager(context)
recyclerView.adapter = adapter
searchBar.clearFocus()
var job: Job? = null
searchBar.setOnQueryTextListener(object : SearchView.OnQueryTextListener {
override fun onQueryTextSubmit(query: String): Boolean {
val coroutineExceptionHandler = CoroutineExceptionHandler { _, throwable ->
throwable.printStackTrace()
}
val prevListSize = bookList.size
bookList.clear()
adapter.notifyItemRangeRemoved(0, prevListSize)
job?.cancel()
job = lifecycleScope.launch(Dispatchers.IO + coroutineExceptionHandler) {
try {
var response: BookListModel? = null
var prevSize = 0
var page = 1
while (response == null || response.meta.is_end.not()) {
response = RetrofitHelper.getInstance().getBooks(apiKey, query, page++)
bookList.addAll(response.documents)
withContext(Dispatchers.Main) {
adapter.notifyItemRangeChanged(prevSize, bookList.size)
}
prevSize = bookList.size
}
} catch (_: CancellationException) {
Log.d("Coroutine", "Job cancelled")
} catch (e: Exception) {
Log.e("Network Error", "Error fetching data", e)
}
}
return true
}
override fun onQueryTextChange(newText: String?): Boolean {
// false if no custom behavior is defined.
return false
}
})
/* val textView: TextView = binding.textHome
homeViewModel.text.observe(viewLifecycleOwner) {
textView.text = it
}*/
return rootView as View
}
}
BookInfoFragment.kt:
class BookInfoFragment : Fragment() {
private lateinit var binding: FragmentBookInfoBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = FragmentBookInfoBinding.inflate(layoutInflater)
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View {
val item = arguments?.getParcelable<BookModel>("item")
binding.textBookTitle.text = item?.title
binding.textAuthor.text =
item?.authors?.joinToString(", ") ?: getString(R.string.unknown_author)
binding.textPublisher.text = item?.publisher
binding.textIsbn.text = item?.isbn
binding.textContent.text = item?.contents
// implementation for fetching book info
binding.floatingActionButton.setOnClickListener {
val crawler = Crawler()
val isbns = binding.textIsbn.text.split(' ')
var bInfos: ArrayList<BookInfo>?
lifecycleScope.launch {
withContext(Dispatchers.IO) {
bInfos = crawler.getBookInfos(isbns)?.let { it1 -> ArrayList(it1) }
bInfos?.forEach {
it.book = item
}
}
if (bInfos != null) {
val action = BookInfoFragmentDirections.actionNavBookInfoToNavMaps(bInfos!!.toTypedArray())
findNavController().navigate(action)
} else {
Toast.makeText(context, getString(R.string.no_book_found), Toast.LENGTH_SHORT).show()
Log.d("BookInfoFragment", "No book found")
}
}
}
Glide.with(this)
.load(item?.thumbnail)
.apply(bitmapTransform(BlurTransformation(25, 3)))
.into(binding.imageBookCoverBlur)
Glide.with(this)
.load(item?.thumbnail)
.into(binding.imageBookCover)
// Inflate the layout for this fragment
return binding.root
}
companion object {
@JvmStatic
fun newInstance(item: BookModel) = BookInfoFragment().apply {
arguments = Bundle().apply {
putParcelable("item", item)
}
}
}
}
MapsFragment.kt:
class MapsFragment : Fragment(), GoogleMap.OnMarkerClickListener {
private val callback = OnMapReadyCallback { googleMap ->
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera.
* In this case, we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to
* install it inside the SupportMapFragment. This method will only be triggered once the
* user has installed Google Play services and returned to the app.
*/
val school = LatLng(37.500062,126.868063)
googleMap.setOnMarkerClickListener(this)
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(school, 20f))
arguments?.getParcelableArray("books")?.forEach {
val book = it as BookInfo
val marker = googleMap.addMarker(
MarkerOptions().position(book.library!!.location).title(book.library!!.getName(requireContext())).snippet(book.loc)
)
marker?.tag = book
}
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
return inflater.inflate(R.layout.fragment_maps, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val mapFragment = childFragmentManager.findFragmentById(R.id.map) as SupportMapFragment?
Log.d("MapsFragment", arguments?.getParcelableArray("books")?.size.toString())
mapFragment?.getMapAsync(callback)
}
override fun onMarkerClick(p0: Marker): Boolean {
val book = p0.tag as BookInfo
ModalBottomSheet().apply {
this.book = book
}.show(requireActivity().supportFragmentManager, ModalBottomSheet.TAG)
return true
}
}
class ModalBottomSheet : BottomSheetDialogFragment() {
lateinit var book: BookInfo
private lateinit var binding: BottomSheetBinding
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
binding = BottomSheetBinding.inflate(inflater, container, false)
binding.textLibraryName.text = book.library!!.getName(requireContext())
binding.textLibraryLocation.text = book.loc
binding.buttonBorrow.setOnClickListener {
MapsFragmentDirections.actionNavMapsToNavBorrow(book).let {
(requireActivity() as AppCompatActivity).supportFragmentManager.findFragmentById(R.id.nav_host_fragment_content_main)!!
.findNavController().navigate(it)
dismiss()
}
}
return binding.root
}
companion object {
const val TAG = "ModalBottomSheet"
}
}
BorrowFragment.kt:
class BorrowFragment : Fragment() {
lateinit var binding: FragmentBorrowBinding
private var adapter: MemoAdapter? = null
private var itemID: Int = 0
private var dbHelper: DBHelper? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View {
binding = FragmentBorrowBinding.inflate(inflater, container, false)
val bInfo = arguments?.getParcelable<BookInfo>("item")
if (bInfo != null) {
val memo = Memo(
bInfo.book!!.title!!,
bInfo.library!!.getName(requireContext()),
LocalDate.now().format(DateTimeFormatter.ISO_LOCAL_DATE).toString(),
LocalDate.now().plusDays(7).format(DateTimeFormatter.ISO_LOCAL_DATE).toString(),
bInfo.book!!.thumbnail!!
)
showManualEntry({ m ->
addMemo(m)
}, memo)
}
val dataList = mutableListOf<MutableMap<String, String>>()
dbHelper = DBHelper(activity)
val db = dbHelper?.readableDatabase
val cursor = db?.rawQuery(DBContract.SQL_LOAD, null, null)
while (cursor?.moveToNext()!!) {
val item = mutableMapOf<String, String>()
item["id"] = cursor.getInt(0).toString()
item["title"] = cursor.getString(1)!!
item["library"] = cursor.getString(2)!!
item["borrow"] = cursor.getString(3)!!
item["due"] = cursor.getString(4)!!
item["image"] = cursor.getString(5)!!
dataList.add(item)
itemID = cursor.getInt(0)
}
cursor.close()
adapter = MemoAdapter(this, dataList)
binding.borrowingBookList.adapter = adapter
binding.fab.setOnClickListener {
showManualEntry({ memo ->
addMemo(memo)
})
}
return binding.root
}
/**
* Calculate duration between two dates in days
* @param fromTime start date
* @param toTime end date
* @return duration between two dates in days
*/
fun calculateDuration(fromTime: LocalDate, toTime: LocalDate): Long {
fromTime.until(toTime, java.time.temporal.ChronoUnit.DAYS)
return fromTime.until(toTime, java.time.temporal.ChronoUnit.DAYS)
}
private fun addMemo(memo: Memo) {
val item = mutableMapOf<String, String>()
itemID++
item["id"] = itemID.toString()
item["title"] = memo.title
item["library"] = memo.library
item["borrow"] = memo.borrow
item["due"] = memo.due
item["image"] = memo.image
adapter!!.datas.add(item)
adapter!!.notifyItemChanged(itemID)
DBContract.insertMemo(requireContext(), itemID, memo)
}
private fun calendarClickListener(
eBinding: EditLayoutBinding,
targetView: TextView
): View.OnClickListener {
return View.OnClickListener {
val today = LocalDate.now()
DatePickerDialog(
requireContext(),
{ _, year, month, dayOfMonth ->
val setDate = Calendar.getInstance()
setDate.set(year, month, dayOfMonth)
targetView.text = LocalDate.of(
setDate.get(Calendar.YEAR),
setDate.get(Calendar.MONTH) + 1,
setDate.get(Calendar.DAY_OF_MONTH)
).format(DateTimeFormatter.ISO_LOCAL_DATE)
// calculate duration and update number picker
if (eBinding.editTextDueDate.text.isNotEmpty() && eBinding.editTextBorrowDate.text.isNotEmpty()) {
val borrowDate = LocalDate.parse(
eBinding.editTextBorrowDate.text,
DateTimeFormatter.ISO_LOCAL_DATE
)
val dueDate =
LocalDate.parse(
eBinding.editTextDueDate.text,
DateTimeFormatter.ISO_LOCAL_DATE
)
val duration = calculateDuration(borrowDate, dueDate)
eBinding.numberPickerDuration.value = duration.toInt()
}
}, today.year, today.monthValue, today.dayOfMonth
).show()
}
}
/**
* Show alert dialog to manually enter the borrowed book information
* @param callback callback function to handle the result
* @param memo default values to show
*/
fun showManualEntry(callback: (Memo) -> Unit, memo: Memo? = null) {
val eBinding = EditLayoutBinding.inflate(layoutInflater).apply {
// configure duration number picker
numberPickerDuration.run {
// min and max value of duration
minValue = 1
maxValue = 100
setOnValueChangedListener { _, _, newVal ->
val borrowDate = LocalDate.parse(
editTextBorrowDate.text,
DateTimeFormatter.ISO_LOCAL_DATE
)
val dueDate = borrowDate.plusDays(newVal.toLong())
editTextDueDate.setText(dueDate.format(DateTimeFormatter.ISO_LOCAL_DATE))
}
}
imageButtonCalendarBorrowDate.setOnClickListener(
calendarClickListener(
this,
editTextBorrowDate
)
)
imageButtonCalendarDueDate.setOnClickListener(
calendarClickListener(
this,
editTextDueDate
)
)
// use provided values if exists
if (memo != null) {
editTextBookTitle.setText(memo.title)
editTextLibrary.setText(memo.library)
editTextBorrowDate.setText(memo.borrow)
editTextDueDate.setText(memo.due)
numberPickerDuration.value = calculateDuration(
LocalDate.parse(memo.borrow, DateTimeFormatter.ISO_LOCAL_DATE),
LocalDate.parse(memo.due, DateTimeFormatter.ISO_LOCAL_DATE)
).toInt()
} else {
// set the default date of due date to today
editTextBorrowDate.setText(
LocalDate.now().format(DateTimeFormatter.ISO_LOCAL_DATE).toString()
)
editTextDueDate.setText(
LocalDate.now().format(DateTimeFormatter.ISO_LOCAL_DATE).toString()
)
}
}
// show alert dialog
AlertDialog.Builder(activity).run {
setTitle(getString(R.string.manual_entry))
setView(eBinding.root)
setPositiveButton("Ok") { _, _ ->
val title = eBinding.editTextBookTitle.text.toString()
val library = eBinding.editTextLibrary.text.toString()
val borrow = eBinding.editTextBorrowDate.text.toString()
val due = eBinding.editTextDueDate.text.toString()
callback(Memo(title, library, borrow, due, memo?.image ?: ""))
}
setNegativeButton("Cancel", null)
show()
}
}
fun delMemo(id: Int) {
val db = dbHelper?.writableDatabase
db?.delete(DBContract.TABLE_NAME, "id=$id", null)
}
fun editMemo(pos: Int, memo: Memo) {
adapter!!.datas[pos]["title"] = memo.title
adapter!!.datas[pos]["library"] = memo.library
adapter!!.datas[pos]["borrow"] = memo.borrow
adapter!!.datas[pos]["due"] = memo.due
adapter!!.notifyItemChanged(pos)
DBContract.updateMemo(requireContext(), pos, memo)
}
}
If my question is not clear, or I'm not giving enough context, I'm sorry. I'm a novice here :(
I clicked on the Home button to go from the Borrow Fragment to the Home Fragment, but it doesn't do anything. I can only pop up to the Home Fragment.
I think you are creating new nav graph instance. Just use Fragment.findNavController()
Use:
findNavController().navigate(
MapsFragmentDirections.actionNavMapsToNavBorrow(book)
)
instead of
MapsFragmentDirections.actionNavMapsToNavBorrow(book).let {
(requireActivity() as AppCompatActivity).supportFragmentManager.findFragmentById(R.id.nav_host_fragment_content_main)!!
.findNavController().navigate(it)
dismiss()
}
Also, you can add android:menuCategory="secondary" in menu items. When using secondary category menu item fragment back stack is resets.