向stackOverflow 中的人员问好
我得到了一个包含3个片段的活动(使用navController(我需要读取其中一个托管片段(GameSessionFragment(中的NFC标签ID(EXTRA_ID(
我的问题是每次我扫描新的NFC标签时;创建";再次,让它把我从呈现的片段中带出来,并导航到";主机";活动,我正在努力避免重新创建主机活动,有什么想法我该怎么做?
如果我不清楚,或者你认为我可能对我的问题有更好的解释,请写在上面,另外,对不起我的英语。。
这是我的代码:
清单:
<activity android:name=".Host" >
<intent-filter>
<action android:name="android.nfc.action.TAG_DISCOVERED" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
主机活动:
class Host : AppCompatActivity() {
var fragment: Fragment? = null
private var mAdapter: NfcAdapter? = null
private var mPendingIntent: PendingIntent? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_host)
//for hide the actionBar (contains Fragment name) on top of the screen
val actionBar = supportActionBar
actionBar?.hide()
val navController = Navigation.findNavController(this, R.id.nav_host_fragment)
val navView = findViewById<BottomNavigationView>(R.id.nav_view)
navView?.setupWithNavController(navController)
NavigationUI.setupWithNavController(navView, navController)
//tries to stop poping the activity each time NFC Tag scanned
mAdapter = NfcAdapter.getDefaultAdapter(this)
mPendingIntent = PendingIntent.getActivity(
this, 0,
Intent(this, javaClass).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0
)
//toGameSession(whatToDO)
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
for (fragment in supportFragmentManager.fragments) {
fragment.onActivityResult(requestCode, resultCode, data)
}
}
override fun onNewIntent(intent: Intent) {
super.onNewIntent(intent)
if (NfcAdapter.ACTION_NDEF_DISCOVERED == intent.action) {
intent.getParcelableArrayExtra(NfcAdapter.EXTRA_ID)?.also { rawMessages ->
val messages: List<NdefMessage> = rawMessages.map { it as NdefMessage }
// Process the messages array.
println(messages)
if (fragment is UserStatusFragment) {
val my: UserStatusFragment = fragment as UserStatusFragment
// Pass intent or its data to the fragment's method
my.processNFC(intent.getStringExtra(messages.toString()))
}
}
}
}
}
这是我想要接收并使用NFC Extra_ID 的片段
GameSessionFragment
class GameSessionFragment : Fragment() {
// TODO: Rename and change types of parameters
private var param1: String? = null
private var param2: String? = null
lateinit var nfcTagId : String
private var mNfcAdapter: NfcAdapter? = null
private var mPendingIntent: PendingIntent? = null
private var mNdefPushMessage: NdefMessage? = null
var mAuth: FirebaseAuth? = null
lateinit var firebaseUser: FirebaseUser
private lateinit var databaseReference: DatabaseReference
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
getNfcTagID()
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_game_session, container, false)
}
private fun getNfcTagID(){
val tagId : ByteArray? = activity?.intent?.getByteArrayExtra(NfcAdapter.EXTRA_ID)
if (tagId != null){
nfcTagId = tagId?.toHexString().toString()
tv_status.text = nfcTagId
}
}
fun ByteArray.toHexString() = joinToString("") { "%02x".format(it) }
fun questPartFinish(questPart: String, useruid: String) {
// val rootRef = FirebaseDatabase.getInstance().reference
// val scoreRef = rootRef.child("Quests").child(useruid).child("$questPart+QuestItemScanned")
// scoreRef.runTransaction(object : Handler(), Transaction.Handler {
// override fun doTransaction(mutableData: MutableData): Transaction.Result {
// val ifFinish =
// mutableData.getValue(Boolean::class.java) ?: return Transaction.success(mutableData)
//
// mutableData.value = true
//// if (operation == "increaseScore") {
//// mutableData.value = score + 50
//// } else if (operation == "decreaseScore") {
//// mutableData.value = score - 1
//// }
// return Transaction.success(mutableData)
// }
//
// override fun onComplete(
// databaseError: DatabaseError?,
// b: Boolean,
// dataSnapshot: DataSnapshot?
// ) {
// }
//
// override fun publish(p0: LogRecord?) {
// TODO("Not yet implemented")
// }
//
// override fun flush() {
// TODO("Not yet implemented")
// }
//
// override fun close() {
// TODO("Not yet implemented")
// }
// })
databaseReference.child("Quests").child(useruid)
.child("$questPart" + "QuestItemScanned").setValue(true)
}
}
我也在这里读到了接收NFC的应用程序总是在前面弹出新的实例
但没有意识到实际需要做什么。
我读到关于使用
mNfcAdapter!!.disableForegroundDispatch(getActivity())
但不确定那件事是否也影响到我。
更新:
感谢:Andrew
非常感谢"enableReaderMode";似乎正是我需要的,我成功地读取了标签id,但出现了两个问题,这两个问题同时发生,当我扫描NFC标签时,我可以在";println";所以现在一切都很好,我成功地阅读了它,但当我试图将它传递到文本视图中时,在片段中,只有当我刷新片段时才会发生这种情况,(还有第二个问题(我看到了文本视图几秒钟,但随后,我的所有布局都消失了(在我的主机活动中的所有片段中(,
收到那条消息";只有创建视图层次结构的原始线程才能接触其视图";
我可以看到那些碎片作品里面的功能,它只是消失的布局,希望你能理解我并会。能够帮助我解决我的问题,如果你认为有更好的方法来描述这个问题,欢迎你说
感谢所有来帮忙的人!
工作乐趣这就是你所需要的!''
var mNfcAdapter:NfcAdapter?=空
fun ByteArray.toHexString() = joinToString("") { "%02x".format(it) }
fun scanForNfcTagId(activity : Activity){
val options = Bundle()
// READER_PRESENCE_CHECK_DELAY is a work around for a Bug in some NFC implementations.
options.putInt(NfcAdapter.EXTRA_READER_PRESENCE_CHECK_DELAY, 1);
mNfcAdapter = NfcAdapter.getDefaultAdapter(activity)
val flags =
NfcAdapter.FLAG_READER_NO_PLATFORM_SOUNDS or
NfcAdapter.FLAG_READER_NFC_A or
NfcAdapter.FLAG_READER_NFC_B or
NfcAdapter.FLAG_READER_NFC_F or
NfcAdapter.FLAG_READER_NFC_V or
NfcAdapter.FLAG_READER_NFC_BARCODE
mNfcAdapter!!.enableReaderMode(activity, NfcAdapter.ReaderCallback { tag ->
activity?.runOnUiThread {
Log.d("WTF", "Tag discovered")
nfcTagId = (tag.id).toHexString()
Toast.makeText(
activity,
"tag detected",
Toast.LENGTH_SHORT
).show()
if (!actualQuest.firstQuestItemScanned) {
hatCallBackAction(activity)
} else if (!actualQuest.secondQuestItemScanned) {
println("scan for pants")
pantsCallBackAction(activity)
} else if (!actualQuest.thirdQuestItemScanned) {
println("scan for shirt")
shirtCallBackAction(activity)
} else {
println("actualQuest" + actualQuest)
Toast.makeText(
activity,
"Quest is Finish! no more to search here",
Toast.LENGTH_LONG
).show()
}
}
}, flags, null)
}
''
使用更新更好的enableReaderMode
API进行NFChttps://developer.android.com/reference/android/nfc/NfcAdapter#enableReaderMode(android.app.Activity,%20android.NfcAdapter.ReaderCallback,%20int,%20android.os.Bundle(
这将在您的应用程序中创建一个新线程,以在发现标签时进行处理,避免使用Intents
获取NFC数据时发生的创建/重新创建/暂停/恢复活动。
然后在onTagDiscovered
回调方法中使用getId
https://developer.android.com/reference/android/nfc/Tag#getId((在Tag
对象上,以获得与Extra_ID
相同的数据
使用enableReaderMode
的示例位于https://stackoverflow.com/a/64441986/2373819
更新
如答案中所述,创建一个新线程来处理NFC数据,并且只有UI线程可以更新UI
同样在示例代码的注释中
// This gets run in a new thread on Tag detection
// Thus cannot directly interact with the UI Thread
public void onTagDiscovered(Tag tag) {
因此,您需要使用一种方法在线程之间进行数据通信。
简单的方法是使用runOnUIThread
https://developer.android.com/reference/android/app/Activity#runOnUiThread(java.lang.可运行(
例如
runOnUiThread(new Runnable() {
@Override
public void run() {
// Set the value of the ID to the textview
textview.setText(iDtext);
}
});