Discussion :

[Kevinevic]

bonjour,
j'ai crée une simple application sur android studio dont la fonction est de lire un tag nfc et de le comparer a une database.
je ne suis pas du domaine ce qui n'aide pas du tout...
Bref après avoir corrigé beaucoup d'erreurs lors de build de l'app je suis confronté à un autre problème.

Sur mon téléphone, l'app crash dès l'ouverture (android 8.1)
idem sur d'autres téléphone (android 13 et +)

Cependant sur ma tablette honor celle-ci s'ouvre sans problème. ne pouvant pas tester l'appli puisque la tablette n'a pas de NFC je suis un peu bloqué.
De plus, je ne peux pas brancher mon tel en usb pour le mode debogage...

J'ai tenté une version app-debug.apk puis app-release.apk puis une version signée etc...

Code :

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1-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: FATAL EXCEPTION: main
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: Process: com.example.simplicims, PID: 25204
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: java.lang.RuntimeException: Unable to resume activity {com.example.simplicims/com.example.simplicims.MainActivity}: java.lang.NullPointerException
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3622)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3662)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2903)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.app.ActivityThread.-wrap11(Unknown Source:0)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1623)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.os.Handler.dispatchMessage(Handler.java:106)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.os.Looper.loop(Looper.java:164)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.app.ActivityThread.main(ActivityThread.java:6548)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at java.lang.reflect.Method.invoke(Native Method)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:865)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: Caused by: java.lang.NullPointerException
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.nfc.NfcAdapter.enableForegroundDispatch(NfcAdapter.java:1319)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at com.example.simplicims.MainActivity.onResume(MainActivity.kt:49)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1355)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.app.Activity.performResume(Activity.java:7131)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3597)
11-29 18:02:02.509 10182 25204 25204 E AndroidRuntime: 	... 10 more
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: FATAL EXCEPTION: main
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: Process: com.example.simplicims, PID: 25228
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: java.lang.RuntimeException: Unable to resume activity {com.example.simplicims/com.example.simplicims.MainActivity}: java.lang.NullPointerException
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3622)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3662)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2903)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.app.ActivityThread.-wrap11(Unknown Source:0)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1623)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.os.Handler.dispatchMessage(Handler.java:106)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.os.Looper.loop(Looper.java:164)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.app.ActivityThread.main(ActivityThread.java:6548)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at java.lang.reflect.Method.invoke(Native Method)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:865)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: Caused by: java.lang.NullPointerException
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.nfc.NfcAdapter.enableForegroundDispatch(NfcAdapter.java:1319)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at com.example.simplicims.MainActivity.onResume(MainActivity.kt:49)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1355)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.app.Activity.performResume(Activity.java:7131)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3597)
11-29 18:02:04.780 10182 25228 25228 E AndroidRuntime: 	... 10 more

Cordialement

[marvincedry]

Solution

Vous devez vérifier que NfcAdapter n'est pas null avant de l'utiliser.

Correction dans MainActivity.kt
override fun onResume() {
super.onResume()

if (nfcAdapter != null) {
nfcAdapter.enableForegroundDispatch(this, pendingIntent, intentFiltersArray, techListsArray)
}
}

[marvincedry]

nfcAdapter = NfcAdapter.getDefaultAdapter(this)

if (nfcAdapter == null) {
Toast.makeText(this, "NFC not supported on this device", Toast.LENGTH_LONG).show()
}


if (!nfcAdapter.isEnabled) {
Toast.makeText(this, "Please enable NFC", Toast.LENGTH_LONG).show()
}

[marvincedry]

package com.example.simplicims

import android.app.PendingIntent
import android.content.Intent
import android.content.IntentFilter
import android.nfc.NfcAdapter
import android.nfc.Tag
import android.os.Bundle
import android.provider.Settings
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity

class MainActivity : AppCompatActivity() {

private var nfcAdapter: NfcAdapter? = null
private var pendingIntent: PendingIntent? = null
private var intentFiltersArray: Array<IntentFilter>? = null
private var techListsArray: Array<Array<String>>? = null

override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)

// Initialisation NFC
nfcAdapter = NfcAdapter.getDefaultAdapter(this)

if (nfcAdapter == null) {
Toast.makeText(this, "NFC not supported on this device", Toast.LENGTH_LONG).show()
finish()
return
}

if (!nfcAdapter!!.isEnabled) {
Toast.makeText(this, "Please enable NFC", Toast.LENGTH_LONG).show()

val intent = Intent(Settings.ACTION_NFC_SETTINGS)
startActivity(intent)
}

// Intent pour NFC foreground dispatch
pendingIntent = PendingIntent.getActivity(
this,
0,
Intent(this, javaClass).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP),
PendingIntent.FLAG_MUTABLE
)

// Filtre NFC
val tagDetected = IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED)
intentFiltersArray = arrayOf(tagDetected)

techListsArray = arrayOf(
arrayOf(android.nfc.tech.NfcA::class.java.name),
arrayOf(android.nfc.tech.NfcB::class.java.name),
arrayOf(android.nfc.tech.NfcF::class.java.name),
arrayOf(android.nfc.tech.NfcV::class.java.name)
)
}

override fun onResume() {
super.onResume()

nfcAdapter?.enableForegroundDispatch(
this,
pendingIntent,
intentFiltersArray,
techListsArray
)
}

override fun onPause() {
super.onPause()

nfcAdapter?.disableForegroundDispatch(this)
}

override fun onNewIntent(intent: Intent) {
super.onNewIntent(intent)

val tag: Tag? = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG)

if (tag != null) {
Toast.makeText(this, "NFC Tag Detected", Toast.LENGTH_SHORT).show()

val tagId = tag.id.joinToString("") { "%02X".format(it) }

Toast.makeText(this, "Tag ID: $tagId", Toast.LENGTH_LONG).show()
}
}
}