我对这个错误感到沮丧 Fragment not attach to an Activity，我有一个 Fragment 启动了一个 Activity，而 Activity 启动了另一个 Activity，依此类推 F -> A1 -> A2 -> A3，在我完成最后一个 { {1}} 我打电话返回托管活动
A3但是当我设置 val intent = Intent(applicationContext, TabbarActivity::class.java)
intent.putExtra("finish", "true")
intent.flags = Intent.FLAG_ACTIVITY_CLEAR_TASK.or(Intent.FLAG_ACTIVITY_NEW_TASK)
startActivity(intent)
finish()
时，它会将我的片段从 Activity 中分离出来，然后我收到此错误 Intent.FLAG_ACTIVITY_CLEAR_TASK，如果我重新运行我的应用程序，一切都会正常工作。
这里是宿主Activity
Fragment not attached to an activity我什么时候收到这个错误？
在完成最后一个活动并且用户返回后，用户可以收到通知，当通知请求我尝试过的上下文时，此方法开始出现错误private var bottomNavigation: BottomNavigationView? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_tabbar)
val finish = intent.getStringExtra("finish")
bottomNavigation = findViewById(R.id.bottomNavigationView)
val navigationController = findNavController(R.id.fragment)
bottomNavigation?.setupWithNavController(navigationController)
bottomNavigation?.itemIconTintList = null
val firstFragment: Fragment = Fragment1()
val secondFragment: Fragment = Fragment2()
val thirdFragment: Fragment = Fragment3()
val forthFragment: Fragment = Fragment4()
var active = firstFragment
supportFragmentManager.beginTransaction().add(R.id.containerb, forthFragment, "4").hide(forthFragment).commit()
supportFragmentManager.beginTransaction().add(R.id.containerb, thirdFragment, "3").hide(thirdFragment).commit()
supportFragmentManager.beginTransaction().add(R.id.containerb, secondFragment, "2").hide(secondFragment).commit()
supportFragmentManager.beginTransaction().add(R.id.containerb, firstFragment, "1").commit()
if (finish.equals("true")){
bottomNavigation?.setSelectedItemId(R.id.ordersFragment);
supportFragmentManager.beginTransaction().hide(active).show(thirdFragment).commit()
active = thirdFragment
}
bottomNavigation?.setOnNavigationItemReselectedListener {
when (it.itemId) {
R.id.Fragment1 -> {
supportFragmentManager.beginTransaction().hide(active).show(firstFragment).commit()
active = firstFragment
}
R.id.Fragment2 -> {
supportFragmentManager.beginTransaction().hide(active).show(secondFragment).commit()
active = secondFragment
}
R.id.Fragment3 -> {
supportFragmentManager.beginTransaction().hide(active).show(thirdFragment).commit()
active = thirdFragment
}
R.id.Fragment4 -> {
supportFragmentManager.beginTransaction().hide(active).show(forthFragment).commit()
active = forthFragment
}
}
true
}
bottomNavigation?.setOnNavigationItemSelectedListener { item ->
when (item.itemId) {
R.id.Fragment1 -> {
supportFragmentManager.beginTransaction().hide(active).show(firstFragment).commit()
active = firstFragment
}
R.id.Fragment2 -> {
supportFragmentManager.beginTransaction().hide(active).show(secondFragment).commit()
active = secondFragment
}
R.id.Fragment3 -> {
supportFragmentManager.beginTransaction().hide(active).show(thirdFragment).commit()
active = thirdFragment
}
R.id.Fragment4 -> {
supportFragmentManager.beginTransaction().hide(active).show(forthFragment).commit()
active = forthFragment
}
}
true
}
}
，以及获取上下文的所有可能性这里是片段3
requireContext(), this@..Activity, applicationContext, activity.contextlogcat 错误
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
createNotificationChannele()
}
private fun newOrderOffers() {
val uid = FirebaseAuth.getInstance().uid ?: ""
val firestore = FirebaseFirestore.getInstance()
val fireRef = firestore.collection("inProcess").whereEqualTo("userUid", uid)
fireRef.addSnapshotListener { value, error ->
if (value != null) {
value.documentChanges.forEach {
if (it.type == DocumentChange.Type.ADDED) {
SendNotificationWhenSelected()
}
}
}
}
}
private fun createNotificationChannele(){
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
val channel = NotificationChannel(chanal_id, chanale_name,
NotificationManager.IMPORTANCE_HIGH).apply {
lightColor = Color.RED
enableLights(true)
}
val manager = this.context?.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
manager.createNotificationChannel(channel)
}
}
private fun SendNotificationWhenSelected(){
val notification =
NotificationCompat.Builder(requireContext(), chanal_id) // the error in this line
.setContentTitle("...")
.setContentText("....")
.setSmallIcon(R.drawable.....)
.setPriority(Notification.PRIORITY_HIGH)
.setAutoCancel(true)
.build()
val notificationManager = NotificationManagerCompat.from(requireView().context)
notificationManager.notify(notification_id, notification)
}
答案 0 :(得分：0)
问题似乎在于旧的 Fragment 仍然存在，并且在与旧的 Activity 分离后仍会收到 Firebase 回调。当旧的 Fragment 分离/销毁时，您需要移除 Firebase 回调。
这就是为什么您在返回 TabbarActivity 时会看到此问题，但在您第一次启动应用程序时却不会。