edit: 2020.4.12 correct typo from Button.performClick() to button.performClick()
I am writing an app which should display a splash page/fragment for a
few seconds at start then display the next fragment in the navgraph. There are seven fragments in the navgraph which I can navigate around those fragments just fine.
The issue is with the splash fragment, I can only get the splash fragment to display/inflate when the button.onClickListener is set to accept a manual user
input -> click. (vs using button.performClick())
The desired end result is to display a fragment layout consisting of an image view and a text view for a few seconds at app start before displaying the next fragment layout in the navgraph, without having the user to click or press anything.
I have tried using threadsleep, a runnable with a handler, and even a while loop with performClick(). None of which have yielded acceptable results. The closest I have come to getting the desired result is the following:
class SplashFragment : Fragment() {
override fun onCreateView(inflater: LayoutInflater,
rootContainer: ViewGroup?,
savedInstanceState: Bundle?): View {
return inflater.inflater(R.layout.fragment_splash, rootContainer, false)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
button.setOnClickListener {
updateABode()
}
// pizzaLoop initialized to give about 4 seconds delay
val pizzaLoop = 1500000000
while (pizzaLoop > 0) {
pizzaLoop--
if (pizzaLoop == 0) {
button.performClick()
}
}
private fun updateABode {
val ABode = "A" // hard coded for testing purposes
when (ABode) {
"B" -> // for testing purposes only -- does nothing
"A" -> findNavController().navigate(R.id.action_splashFragment_to_firmwareFragment)
}
}
}
With the pizzaLoop installed, the splash fragment will not inflate, but I do see the delay via the firmware screen update. (intially all I get is a white blank screen then subsequent calls to the SplashFragment class show nothing but the firmwareFragment screen (next in the navgraph) -- and the pizzaLoop delay is noticable).
When I comment out the pizzaLoop then the splash fragment displays as intended but I have to click the button to bring up the next fragment in the navgraph (the rest of the navgraph works fine).
It's like the button.performClick() method is preventing the inflation of the splash fragment.
EDIT: 2020.4.12 TO PROPERLY POST SOLUTION.
class SplashFragment : Fragment() {
private val handler: Handler = Handler()
private val updateRunnable: Runnable = Runnable { updateABode() }
override fun onCreateView(inflater: LayoutInflater,
rootContainer: ViewGroup?,
savedInstanceState: Bundle?): View {
return inflater.inflater(R.layout.fragment_splash, rootContainer, false)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
button.setOnClickListener {
handler.removeCallbacks(updateRunnable)
}
handler.postDelayed(updateRunnable, 4000)
}
private fun updateABode {
val ABode = "A" // hard coded for testing purposes
when (ABode) {
"B" -> // for testing purposes only -- does nothing
"A" -> findNavController().navigate(R.id.action_splashFragment_to_firmwareFragment)
}
}
}
Related
I have a simple app for testing. It has a "basic activity" that Android Studio brings by default. Also a Google maps fragment shown in the basic activity (the code is at the end of the post).
As you all know, the basic activity has a floating button like this:
The main problem is that I'm completely new to working with fragments, and I don't quite understand how they work (I am working on it) but what I want to do is that: by clicking on the floating button, the map is "restarted", reloading again and cleaning it of markers that the user has placed.
What would be the correct way to do this?
I have found several suggestions but I can't get them to work or I can't see how to implement them correctly. One of the ways I have tried is to detach and attach the map fragment, but this causes it to crash and shows no results. The code is the following, which I add in the floating button listener:
val frg : Fragment? = supportFragmentManager.findFragmentById(R.id.map);
val frgTransac = supportFragmentManager.beginTransaction();
if (frg != null) {
frgTransac.detach(frg);
frgTransac.attach(frg);
frgTransac.commit();
}
Another option is to use "googleMap.clear" but I don't know exactly how to get access to that object from the floating button listener.
I hope you can help me with this and, above all, understand how the fragments work and what I am doing wrong.
Main activity
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
setSupportActionBar(findViewById(R.id.toolbar))
findViewById<FloatingActionButton>(R.id.fab).setOnClickListener { view ->
// CLEAR MAP FROM HERE
}
}
override fun onCreateOptionsMenu(menu: Menu): Boolean {
menuInflater.inflate(R.menu.menu_main, menu)
return true
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
return when (item.itemId) {
R.id.action_settings -> true
else -> super.onOptionsItemSelected(item)
}
}
}
Map Fragment
class FMaps : Fragment() {
private val callback = OnMapReadyCallback { googleMap ->
val sydney = LatLng(-34.0, 151.0)
googleMap.addMarker(MarkerOptions().position(sydney).title("Marker in Sydney"))
googleMap.moveCamera(CameraUpdateFactory.newLatLng(sydney))
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
return inflater.inflate(R.layout.fragment_f_maps, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val mapFragment = childFragmentManager.findFragmentById(R.id.map) as SupportMapFragment?
mapFragment?.getMapAsync(callback)
}
}
You can use custom interface defined in the fragment and then called from the activity when the button is pressed (example how to create interface here: Communicating between a fragment and an activity - best practices). When you press the button and the interface is called, you can just refresh the map using mapFragment?.getMapAsync(callback) inside the fragment.
I'm creating a shopping app where the user can choose next product from the fragment. That will open the next fragment of the same class with more products and so on. I want to use swipe to dismiss behaviour, so when I swipe my finger down I dissmiss the current fragment. It's essential that while swiping the current fragment the user will be able to see the fragment underneath, so I can only use add instead of replace. Here's the problem: When I use add in my fragment manager, the created fragments UI's overlap, which makes the user swipe multiple fragments at once and not show swiping animation. The fragment uses one xml layout so it shares id across all fragments so I have no way of controlling which layouts are disabled. How do I make the user only swipe one fragment/disable touching fragments underneath? The swipe to dissmis is working well with replace but that's not the point. Here's my code.
Activity:
class PullDismissActivity : AppCompatActivity(), PullDismissLayout.Listener {
private lateinit var viewModel: StackingFragmentsViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_pulldismiss)
viewModel = ViewModelProvider(this).get(StackingFragmentsViewModel::class.java)
supportFragmentManager.beginTransaction()
.add(R.id.pull, SwipeFragment(), null)
.addToBackStack(null) // name can be null
.commit()
val layout = findViewById<PullDismissLayout>(R.id.pull)
layout.setListener(this)
}
override fun onDismissed() {
viewModel.popBackStack()
supportFragmentManager.popBackStack()
}
override fun onShouldInterceptTouchEvent(): Boolean {
return false
}
Fragment:
class SwipeFragment : Fragment() {
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val viewModel = ViewModelProvider(requireActivity()).get(StackingFragmentsViewModel::class.java)
viewModel.addFragment(this.hashCode())
val fragid = view.findViewById<TextView>(R.id.fragid)
fragid?.text = System.currentTimeMillis().toString()
val button = view.findViewById<Button>(R.id.button)
button.setOnClickListener {
requireActivity().supportFragmentManager.beginTransaction()
.add(R.id.pull, SwipeFragment(), null)
.addToBackStack(null)
.commit()
}
}
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment,container,false)
}
I have the weirdest bug on Kotlin, and after two days of trying I finally asking for help.
The problem is simple : I have two fragment and one activity, the first fragment A is a form, with a validate button, when I click on validate, the fragment B replace the fragment A, and if I press back, the fragment A show up again with the form filled.
My problem is that after the fragment is shown again, I can click on the button but the listener is not call, so I can't go to the fragment B again. The strange thing is that the other listener are properly working, so I'm thinking it's because the previous fragment is catching the onClick, but idk what to do. Here is some code :
ViewUtils :
fun addFragment(activity: Activity, fragment: androidx.fragment.app.Fragment, container: Int) {
val fragmentManager = (activity as AppCompatActivity).supportFragmentManager
val pendingTransaction = fragmentManager.beginTransaction().add(container, fragment, fragment.javaClass.name)
pendingTransaction.commitAllowingStateLoss()
}
fun replaceFragment(manager: FragmentManager, fragment: androidx.fragment.app.Fragment, container: Int) {
if (fragment.isAdded) return
val pendingTransaction = mangaer.beginTransaction()
pendingTransaction.replace(container, fragment, fragment.javaClass.name)
pendingTransaction.commitAllowingStateLoss()
}
fun removeFragment(activity: Activity, fragment: Fragment) {
val manager = (activity as AppCompatActivity).supportFragmentManager
val trans = manager.beginTransaction()
trans.remove(fragment)
trans.commit()
manager.popBackStack()
}
Activity :
fun displayFragmentA() {
ViewUtils.replaceFragment(supportFragmentManager, FragmentA,
R.id.fragmentLayout)
}
fun FragmentB() {
ViewUtils.replaceFragment(supportFragmentManager, FragmentB,
R.id.fragmentLayout)
}
Fragment A
class AFragment : BaseFragment(), AContract.View {
companion object {
#JvmStatic
fun newInstance(): AFragment {
val fragment = AFragment()
return fragment
}
}
#Inject
lateinit var APresenter: AContract.Presenter<AContract.View>
//end region
//region lifecycle
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment_A_layout, container, false)
}
override fun onResume() {
super.onResume()
button_validate.setOnClickListener {
presenter.goToNextStep()
}
}
override fun onAttach(context: Context) {
AndroidSupportInjection.inject(this)
super.onAttach(context)
}
The listener was set in the onViewCreated but I tried moving it to onResume (didn't change anything)
Fragment B code is not important I think, but I can add it if it helps.
Any help is welcome, I really don't know what's going on, the replace/add methods were there before I came to the project, they are not perfect but they are working elsewhere on the project.
I try using breakpoint, the button is not null but we never enter the listener.
Edit : I tried on 3 differents devices, I don't have the bug with a Sony Android 9, but with Huawei et One plus 6 Android 10, the problem persist ..
Ok so after asking to a lot of people, the only solution I found is not using kotlin.synthetic, and using findById instead :
view.findViewById<Button>(R.id.button_validate.setOnClickListener
I have made an app in kotlin through the android studio, Now I have used ViewModels to save UI data while phone rotation(configuration change), i also used onSaveInstanceState to save data while pressing back button but it's not working.
The code is below
fragOne.kt
class fragOne : Fragment() {
private lateinit var viewModel: fragViewModel
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
if(savedInstanceState!=null){
with(savedInstanceState) {
viewModel.num=getInt("number")
}
}
// Inflate the layout for this fragment
var binding = DataBindingUtil.inflate<FragmentFragoneBinding>(
inflater,
R.layout.fragment_fragone,
container,
false
)
viewModel = ViewModelProviders.of(this).get(fragViewModel::class.java)
// function to update number
fun updateNumber()
{
binding.number.text="${viewModel.num}"
}
updateNumber()
// setting on Click listener for add button
binding.add.setOnClickListener()
{
viewModel.addFive()
updateNumber()
}
// setting on on Click Listener for minus button
binding.minus.setOnClickListener()
{
viewModel.minusOne()
updateNumber()
}
return binding.root
}
override fun onSaveInstanceState(outState: Bundle) {
// Save the user's current game state
outState?.run {
putInt("number",viewModel.num)
}
// Always call the superclass so it can save the view hierarchy state
if (outState != null) {
super.onSaveInstanceState(outState)
}
}
}
ViewModelclass
class fragViewModel:ViewModel()
{
// Initializing num=0
var num=0
// Functions to add five or subtract one
fun addFive()
{
num=num+5
}
fun minusOne()
{
num=num-1
}
}
please tell me because data is not saved when I press back
You can override onBackPressed to do your state saving:
How to implement onBackPressed() in Fragments?
Remember to call super, so that is does also do the back command!
You could also do like the below:
// This callback will only be called when MyFragment is at least Started.
val callback = requireActivity().onBackPressedDispatcher.addCallback(this) {
// Handle the back button event
}
Really good read: https://developer.android.com/guide/navigation/navigation-custom-back
Back navigation is how users move backward through the history of screens they previously visited. All Android devices provide a Back button for this type of navigation, so you should not add a Back button to your app’s UI. Depending on the user’s Android device, this button might be a physical button or a software button.
Ref:
How to show warning message when back button is pressed in fragments
Example:
Ensure your Activity extends AppCompatActivity
class MyFragment : Fragment() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
viewModel = ViewModelProviders.of(this).get(fragViewModel::class.java)
val prefs = activity.getSharedPreferences("Key")
int num = prefs.get("number", -999)
if(num != -999) {
viewModel.num = num
}
val callback = requireActivity().onBackPressedDispatcher.addCallback(this) {
prefs.edit().putInt("number", viewModel.num).apply()
}
}
...
}
This question already has an answer here:
Android - Manage layouts landscape
(1 answer)
Closed 4 years ago.
I'm facing this problem from a week without success.
I'm trying to load two different fragments: PortraitTestFrag.java and LandscapeTestFrag.java depending on Activity host orientation.
Theese Fragments are loaded inside /layout/activity_main.xml and /layout-land/activity_main.xml like this:
<fragment
android:id="#+id/navigationContainerFragment"
android:name="class name#"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
What I want is when my Activity host is portrait, PortraitTestFrag is loaded and show. When my Activity is landscape then LandscapeTestFrag should load and show.
Problem is that PortraitTestFrag is visible at the startup but when device is rotating LandscapeTestFrag is never show even Activity is destroyed and recreated. It seem the first loaded Fragment has the priority.
What could be the problem?
I don't recommend you to replace fragment on orientation changes at least because you will loose your data saved to bundle or persisted inside ViewModel/Presenter/etc.
It is probably better to use DI or fabrics to change implementation of orientation-specific logic inside fragment.
If you really want to change whole fragment, you can create a proxy fragment which manages switch logic:
abstract class BaseSwitchFragment : Fragment() {
companion object {
private const val KEY_ORIENTATION = "ORIENTATION"
private const val CHILD_TAG = "CHILD_TAG"
}
private var prevOrientation: Int? = null
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
return inflater.inflate(R.layout.fragment_switch, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
prevOrientation = savedInstanceState?.getInt(BaseSwitchFragment.KEY_ORIENTATION)
if (prevOrientation != resources.configuration.orientation) {
childFragmentManager.beginTransaction()
.replace(R.id.fragmentContainer, buildFragment(), CHILD_TAG)
.commit()
}
prevOrientation = resources.configuration.orientation
super.onViewCreated(view, savedInstanceState)
}
override fun onSaveInstanceState(outState: Bundle) {
outState.putInt(KEY_ORIENTATION, resources.configuration.orientation)
super.onSaveInstanceState(outState)
}
private fun buildFragment(): Fragment {
if (resources.configuration.orientation == Configuration.ORIENTATION_PORTRAIT) {
return buildPortraitFragment()
} else {
return buildLandscapeFragment()
}
}
protected abstract fun buildPortraitFragment(): Fragment
protected abstract fun buildLandscapeFragment(): Fragment
}
I have not tested this code, but probably it should work. Also I believe that it is possible to optimize this code to prevent recreation of child fragment if it is going to be removed.