如何解决android导航组件使用viewpager2和底部导航导航到其他图形中的片段
我在MainActivity中有四个导航。
home_navigation (homeFragment-> homereportFragment)
device_navigation (devicefragment-> deviceUserFragment-> deviceScanFragment)
和config_navigation,automation_navigation ..
我想移到homeFragment中的deviceUserFragment
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".view.main.MainActivity">
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="@+id/bottom_nav"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:menu="@menu/menu_bottom" />
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/slider_main"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/bottom_nav" />
</androidx.constraintlayout.widget.ConstraintLayout>
private val mOnNavigationItemselectedListener =
BottomNavigationView.OnNavigationItemSelectedListener { item ->
when (item.itemId) {
R.id.home_navigation -> {
slider_main.currentItem = 0
return@OnNavigationItemSelectedListener true
}
R.id.device_navigation -> {
slider_main.currentItem = 1
return@OnNavigationItemSelectedListener true
}
R.id.automation_navigation -> {
slider_main.currentItem = 2
return@OnNavigationItemSelectedListener true
}
R.id.config_navigation -> {
slider_main.currentItem = 3
return@OnNavigationItemSelectedListener true
}
}
false
}
private val onpage = object : ViewPager2.OnPageChangeCallback() {
override fun onPageScrollStateChanged(state: Int) {
}
override fun onPageScrolled(
position: Int,positionOffset: Float,positionOffsetPixels: Int
) {
}
override fun onPageSelected(position: Int) {
bottom_nav.menu.getItem(position).isChecked = true
}
}
private fun initViewPager() {
viewpagerAdapter = SliderAdapterMain(this)
slider_main.apply {
adapter = viewpagerAdapter
registerOnPageChangeCallback(onpage)
}
bottom_nav.setonNavigationItemSelectedListener(mOnNavigationItemselectedListener)
}
带有viewPager2和底部导航的MainActivity代码
home_reistdevice_button.setonClickListener {
activity!!.bottom_nav.selectedItemId = R.id.device_navigation
}
它是homeFragment中的按钮。 但是按钮会导致deviceFragment。
我试图在home_navigation图中添加deviceUserFragment。 但这不适用于底部导航项。
我认为我应该将值homeFragment传递给deviceFragment。
因此,如果deiviceFragment获得价值,请在deviceFragment启动后立即导航至deviceUserFragment。
有人告诉我怎么做。
或者告诉我最好的方法。
@Edit 2020-09-03 我找到了解决方案。 解决方法是在ContainerBragmnet中添加onBacklistener
class HomeContainerFragment : Fragment() {
private var navController:NavController?=null
override fun onCreateView(
inflater: LayoutInflater,container: ViewGroup?,savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_home_container,container,false)
}
override fun onViewCreated(view: View,savedInstanceState: Bundle?) {
super.onViewCreated(view,savedInstanceState)
val navHostFragment = childFragmentManager.findFragmentById(R.id.home_nav_host) as NavHostFragment?
navController = navHostFragment?.navController
listenOnBackpressed()
}
private fun listenOnBackpressed(){
requireActivity().onBackpresseddispatcher.addCallback(viewLifecycleOwner,callback)
}
override fun onResume() {
super.onResume()
callback.isEnabled = true
}
override fun onPause() {
super.onPause()
callback.isEnabled =false
}
private fun dialog_build(){
val builder = AlertDialog.Builder(ContextThemeWrapper(activity,R.style.AlertDialog))
builder.setTitle("App terminate")
builder.setMessage("Are you terminating APP?")
builder.setPositiveButton("terminate") { _,_ ->
activity?.finishAffinity()
}
builder.setNegativeButton("cancel") { _,_ ->
}
builder.show()
}
val callback = object : OnBackpressedCallback(false) {
override fun handleOnBackpressed() {
var backkeytime: Long = 0
lateinit var toast: Toast
if(navController?.currentDestination?.id == navController?.graph?.startDestination){
isEnabled = false
dialog_build()
isEnabled = true
}
else{
navController?.navigateUp()
}
}
}
}
我的整个项目结构是1个活动4个ContainerFragment(4个导航)
MainActivity(ViewPager2,BottomNavigation)
-
HomeContainerFragment(FragmentContainerView-home_navigation)
(在导航中)-HomeFragment -HomeReportFragment
-.. -
DeviceContainerFragment
-
...
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