Develop Reference

SharedPreferences not working when Activity is started from somewhere else?

I have a ThreadActivity with two functions, saveContacts and loadContacts. They both use sharedpreferences and Gson to save an ArrayList consisting of Objects called SimpleContacts. Somehow it cannot retrieve data from sharedpreferences once I start the Activity from somewhere else. (I tried loading instantly after saving and that works, but not if I close the Activity and re-open it)
The save function:
private fun saveContact() {
val gson = Gson()
val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(applicationContext)
try {
val editor = sharedPreferences.edit()
val json = gson.toJson(participants)
editor.putString(threadId.toString()+"_Contact", json)
editor.apply()
} catch(e: Exception) {
e.printStackTrace()
}
}
The load function:
private fun loadContact() {
val gson = Gson()
val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(applicationContext)
val type = object : TypeToken<ArrayList<SimpleContact?>?>() {}.type
try {
val json = sharedPreferences.getString(threadId.toString()+"_Contact", "")
participants = gson.fromJson(json, type)
} catch(e: Exception) {
e.printStackTrace()
}
}
I have 2 Activities that can open this ThreadActivity, if I start it from the same one, it all works perfectly fine. But when I use the other Activity to start it, the sharedPrefs are empty.
Launch Activity that works (I don't know if its because its the way the Intent is build so I will write them both here):
private fun launchThreadActivity(phoneNumber: String, name: String) {
hideKeyboard()
val text = intent.getStringExtra(Intent.EXTRA_TEXT) ?: ""
val numbers = phoneNumber.split(";").toSet()
val number = if (numbers.size == 1) phoneNumber else Gson().toJson(numbers)
Intent(this, ThreadActivity::class.java).apply {
putExtra(THREAD_ID, getThreadId(numbers))
putExtra(THREAD_TITLE, name)
putExtra(THREAD_TEXT, text)
putExtra(THREAD_NUMBER, number)
if (intent.action == Intent.ACTION_SEND && intent.extras?.containsKey(Intent.EXTRA_STREAM) == true) {
val uri = intent.getParcelableExtra<Uri>(Intent.EXTRA_STREAM)
putExtra(THREAD_ATTACHMENT_URI, uri?.toString())
} else if (intent.action == Intent.ACTION_SEND_MULTIPLE && intent.extras?.containsKey(Intent.EXTRA_STREAM) == true) {
val uris = intent.getParcelableArrayListExtra<Uri>(Intent.EXTRA_STREAM)
putExtra(THREAD_ATTACHMENT_URIS, uris)
}
startActivity(this)
}
}
Start Activity that does not work:
Intent(this, ThreadActivity::class.java).apply {
putExtra(THREAD_ID, (it as Conversation).threadId)
putExtra(THREAD_TITLE, it.title)
putExtra("fromMain", true)
startActivity(this)
}

Nevermind, it was my mistake.
When saveContact was called the threadId was not initialized yet. So basically the keys were always different.

WalletConnectV1 kotlin JSON_RPC method doesn't show pop up on metamask

I am a beginner in android application development(Kotlin) and recently I was handover a project on NFT which involves walletConnect integration & for that I am using the walletConnectV1 library.
Fetching the public key and Connecting with metamask was not so hard but I am struggling when it comes to signing methods.
if anyone can help me with, how to sign messages and transactions or what I was doing wrong all this time that would really help me.
Thank you
Connect Button Click Listener
screen_main_connect_button.setOnClickListener {
try {
ExampleApplication.resetSession()
ExampleApplication.session.addCallback(this)
val i = Intent(Intent.ACTION_VIEW, Uri.parse(ExampleApplication.config.toWCUri()))
startActivity(i)
} catch (e: ActivityNotFoundException) {
// open play store
} catch (e: Exception) {
//handle exceptions
}
}
Response after the session was approved
private fun sessionApproved() {
uiScope.launch {
val account = session.approvedAccounts()?.get(0)?:""
screen_main_status.text = "Connected: $account"
screen_main_connect_button.visibility = View.GONE
screen_main_disconnect_button.visibility = View.VISIBLE
screen_main_tx_button.visibility = View.VISIBLE
val job = async {
personalSign(
"Sign this message of mine to this address",
account) {
Log.d(TAG, "sessionApproved: ${it.result}")
}
val intent = Intent(Intent.ACTION_VIEW)
intent.data = Uri.parse("wc:")
intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK
startActivity(intent)
}
}
}
private fun personalSign(
message: String,
address: String,
response: (Session.MethodCall.Response) -> Unit
) {
val id = System.currentTimeMillis()
val messageParam = if (message.hasHexPrefix()) message else message.toHex()
session.performMethodCall(
Session.MethodCall.Custom(
id, "personal_sign", listOf(messageParam, address)
)
) { response(it) }
}

How to fix crash issue in NFC Tag Writer app due to UnsupportedOperationException in android

I m trying to implement NFC writer app in android 11 in wear os, but im getting java.lang.UnsupportedOperationException when im trying to add this below code in on resume callback ,can some one please help me to fix this issue
override fun onResume() {
super.onResume()
nfcAdapter?.let {
enableNFCInForeground(it, this, javaClass)
}
}
override fun onPause() {
super.onPause()
nfcAdapter?.let {
disableNFCInForeground(it, this)
}
}
and i used this code for enableNFCInForeground
private fun <T> enableNFCInForeground(nfcAdapter: NfcAdapter, activity: Activity, classType: Class<T>) {
val pendingIntent = PendingIntent.getActivity(
activity, 0,
Intent(activity, classType).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0
)
// val nfcIntentFilter = IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED)
val nfcIntentFilter = IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED).apply {
try {
addDataType("text/plain")
} catch (e: IntentFilter.MalformedMimeTypeException) {
throw RuntimeException("fail", e)
}
}
val filters = arrayOf(nfcIntentFilter)
val techLists =
arrayOf(arrayOf(Ndef::class.java.name), arrayOf(NdefFormatable::class.java.name))
nfcAdapter.enableForegroundDispatch(activity, pendingIntent, filters, techLists)
}
and for disableNFCInForeground
private fun disableNFCInForeground(nfcAdapter: NfcAdapter, activity: Activity) {
nfcAdapter.disableForegroundDispatch(activity)
}
Thanks in advance

How to resolve the error "LifecycleOwners must call register before they are STARTED"

I am using registerForActivityResult for google sign in implementation in my development. Everything was working fine until I upgraded my fragment dependency to 1.3.0-beta01. The application current crash with the error
java.lang.IllegalStateException: LifecycleOwner SignupChoicesFragment{8e0e269} (193105b9-afe2-4941-a368-266dbc433258) id=0x7f090139} is attempting to register while current state is RESUMED. LifecycleOwners must call register before they are STARTED.
I have used the function before oncreate using lazy loading but it wont work still.
class SignupChoicesFragment : DaggerFragment() {
#Inject
lateinit var viewModelProviderFactory: ViewModelFactory
val userViewModel: UserViewModel by lazy {
ViewModelProvider(this, viewModelProviderFactory).get(UserViewModel::class.java)
}
#Inject
lateinit var mGoogleSignInClient:GoogleSignInClient
val arg:SignupChoicesFragmentArgs by navArgs()
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_signup_choices, container, false)
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
google_sign_in_button.setOnClickListener {
val intent = mGoogleSignInClient.signInIntent
val launcher = registerForActivityResult(ActivityResultContracts.StartActivityForResult(), ActivityResultCallback {result->
if (result.resultCode == Activity.RESULT_OK) {
val task = GoogleSignIn.getSignedInAccountFromIntent(result.data)
task.addOnCompleteListener {
if (it.isSuccessful) {
val account: GoogleSignInAccount? =
it.getResult(ApiException::class.java)
val idToken = it.result?.idToken
val email = account?.email
val lastName = account?.familyName
val firstName = account?.givenName
val otherName = account?.displayName
val imageUrl = account?.photoUrl
val category = arg.category
val newUser = User()
newUser.firstName = firstName
newUser.lastName = lastName
newUser.otherName = otherName
newUser.category = category
newUser.email = email
newUser.imageUrl = imageUrl.toString()
userViewModel.currentUser = newUser
newUser.token = idToken
i(title, "idToken $idToken")
requireActivity().gdToast("Authentication successful", Gravity.BOTTOM)
val action = SignupChoicesFragmentDirections.actionSignupChoicesFragmentToEmailSignupFragment()
action.newUser = newUser
goto(action)
} else {
requireActivity().gdToast(
"Authentication Unsuccessful",
Gravity.BOTTOM
)
Log.i(title, "Task not successful")
}
}
} else {
Log.i(title, "OKCODE ${Activity.RESULT_OK} RESULTCODE ${result.resultCode}")
}
}).launch(intent)
}
}

For me, the issue was that I was calling registerForActivityResult within an onClickListener which was only invoked on clicking a button (the app at this point is in state RESUMED). Moving the call outside the button's onClickListener and into the Activity's onCreate method fixed it.

quote from documentation
registerForActivityResult() is safe to call before your fragment or activity is created, allowing it to be used directly when declaring member variables for the returned ActivityResultLauncher instances.
Note: While it is safe to call registerForActivityResult() before your fragment or activity is created, you cannot launch the ActivityResultLauncher until the fragment or activity's Lifecycle has reached CREATED.
so to solve your issue move your register call outside the onCreate() and put it in fragment scope, and on google_sign_in_button click-listener call launch function
Note: if you are using Kotlin-Android-Extention move your click-listener call to onViewCreated()

If you are using a Fragment, please make sure that you are NOT performing the registerForActivityResult on the activity. Fragments also have a registerForActivityResult and that's the one you should use.

you must remove val launcher = registerForActivityResult... out of the setOnClickListener, then save it in a variable, in your example is launcher and in the setOnClickListener execute the variable with .launch, in your example es launcher.
your code would look like this
google_sign_in_button.setOnClickListener {
val intent = mGoogleSignInClient.signInIntent
launcher.launch(intent)
}
private val launcher = registerForActivityResult(ActivityResultContracts.StartActivityForResult(), ActivityResultCallback {result->
if (result.resultCode == Activity.RESULT_OK) {
val task = GoogleSignIn.getSignedInAccountFromIntent(result.data)
task.addOnCompleteListener {
if (it.isSuccessful) {
val account: GoogleSignInAccount? =
it.getResult(ApiException::class.java)
val idToken = it.result?.idToken
val email = account?.email
val lastName = account?.familyName
val firstName = account?.givenName
val otherName = account?.displayName
val imageUrl = account?.photoUrl
val category = arg.category
val newUser = User()
newUser.firstName = firstName
newUser.lastName = lastName
newUser.otherName = otherName
newUser.category = category
newUser.email = email
newUser.imageUrl = imageUrl.toString()
userViewModel.currentUser = newUser
newUser.token = idToken
i(title, "idToken $idToken")
requireActivity().gdToast("Authentication successful", Gravity.BOTTOM)
val action = SignupChoicesFragmentDirections.actionSignupChoicesFragmentToEmailSignupFragment()
action.newUser = newUser
goto(action)
} else {
requireActivity().gdToast(
"Authentication Unsuccessful",
Gravity.BOTTOM
)
Log.i(title, "Task not successful")
}
}
} else {
Log.i(title, "OKCODE ${Activity.RESULT_OK} RESULTCODE ${result.resultCode}")
}
})
Source : https://medium.com/codex/android-runtime-permissions-using-registerforactivityresult-68c4eb3c0b61

registerForActivityResult() is safe to call before your fragment or activity is created, allowing it to be used directly when declaring member variables for the returned ActivityResultLauncher instances.
you should call registerForActivityResult before view created. member variables or onCreate()

If you are working with any third party library then it may happens that you can't see the "registerForActivityResult" in your code but it should be present in classes provided by that same library.
So in this case I will suggest to move out the lines which is related to that library from any listener to the onCreate method.
for example -
btnBackup.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final RoomBackup roomBackup = new RoomBackup(GoogleDriveActivity.this);
roomBackup.database(LocalDataBase.getInstance(getApplicationContext()));
roomBackup.enableLogDebug(true);
roomBackup.backupIsEncrypted(false);
roomBackup.backupLocation(RoomBackup.BACKUP_FILE_LOCATION_INTERNAL);
roomBackup.onCompleteListener((success, message, exitCode) -> {
Log.d(TAG, "success: " + success + ", message: " + message + ", exitCode: " + exitCode);
if (success) roomBackup.restartApp(new Intent(getApplicationContext(), GoogleDriveActivity.class));
});
roomBackup.restore();
}
});
//// remove other code from listener and shift in onCreate
roomBackup = new RoomBackup(GoogleDriveActivity.this);
roomBackup.database(LocalDataBase.getInstance(getApplicationContext()));
roomBackup.enableLogDebug(true);
roomBackup.backupIsEncrypted(false);
roomBackup.backupLocation(RoomBackup.BACKUP_FILE_LOCATION_INTERNAL);
roomBackup.maxFileCount(5);
roomBackup.onCompleteListener((success, message, exitCode) -> {
Log.d(TAG, "success: " + success + ", message: " + message + ", exitCode: " + exitCode);
if (success) roomBackup.restartApp(new Intent(getApplicationContext(), GoogleDriveActivity.class));
});
/// you can keep only required lines in listener
btnBackup.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
roomBackup.backup();
}
});
That's it!

Found the same issue and manage to get to work with some magic.
In my case, it was happening in an Activity, so I went about it as such:
//...other bits
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(binding.root)
// doing the setup here
setupViews()
}
private fun setupViews() {
val buttonLauncher = navigator.gotoScreenForResult(this) { success ->
if (success) {
setResult(Activity.RESULT_OK)
finish()
}
}
binding.myButton.setOnClickListener {
buttonLauncher.launch(Unit)
}
Where the navigator.gotoScreenForResult would look like the following:
override fun gotoScreenForResult(context: AppCompatActivity, callback: (Boolean) -> Unit): ActivityResultLauncher<Unit> {
val contract = object : ActivityResultContract<Unit, Boolean>() {
override fun createIntent(context: Context, input: Unit?): Intent {
return Intent(context, MyNextActivity::class.java)
}
override fun parseResult(resultCode: Int, intent: Intent?): Boolean {
return resultCode == Activity.RESULT_OK
}
}
return context.registerForActivityResult(contract) { callback(it) }
}
Just make sure the setupViews is done within the onCreate and not on the resume step.

Detect NFC tag through all the activities

I'm working on Android NFC based application with requirement of continuously read/write data to SLIX-2(ICode) tag from any activity.
As of now, application starts to initialize NFCManager which does most of the heavy lifting for Tag detection, continuously polling for presence check, read & write data.
BaseActivity does initialization of ANFCManager with other required work such as pending restart Intent, check nfc adapter, enableForegroundDispatch, ...
private fun initField() {
mNfcManager = ANfcManager(this)
}
private fun createPendingRestartIntent() {
pendingIntent = PendingIntent.getActivity(this, 0, Intent(this, javaClass)
.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0
)
}
override fun onResume() {
super.onResume()
try {
if(mNfcManager.checkNfcPowerStatus()) // NfcAdapter enabled or not
setReadyToHandleTag()
else Log.w(TAG, "Nfc is not supported or disabled.")
} catch (e: AcmNfcManager.NfcNotEnabledException) {
Log.e(TAG, "Nfc not enabled", e)
}
}
private fun setReadyToHandleTag() {
try {
TECHLISTS = arrayOf(arrayOf(IsoDep::class.java.name), arrayOf(NfcV::class.java.name),
arrayOf(NfcA::class.java.name), arrayOf(NfcB::class.java.name),
arrayOf(NfcF::class.java.name),arrayOf(Ndef::class.java.name),
arrayOf(NdefFormatable::class.java.name))
val tagDetected = IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED)
tagDetected.addCategory(Intent.CATEGORY_DEFAULT)
TAGFILTERS = arrayOf(tagDetected)
} catch (e: Exception) {
Log.e(TAG, "TECH or TAG filter no detected!!!" )
}
pendingIntent?.let { mNfcManager.enableForegroundDispatch(this, it, TAGFILTERS, TECHLISTS) }
}
override fun onNewIntent(intent: Intent) {
super.onNewIntent(intent)
nfcState = mNfcManager.filterIntent(intent)
dispatchActionOnTag(nfcState)
}
// this abs function will provide the Tag state in the corresponding class
abstract fun dispatchActionOnTag(tag: Boolean)
Each Activity has NfcListener for tag detection and will do the read/write using ANfcManager API's. Also to continuously checking the tag presence, using handler with looper internal class inside NFC Manager for presence check.
Here is the function inside ActivityA which trigger the method after tag detection as well as presence check thread,
override fun dispatchActionOnTag(tag: Boolean) {
mNfcStatus = tag
if (nfcStateListener() != null) {
nfcStateListener().updateNfcState(tag)
mNfcManager.startTagCheck() // presence check handler every x sec
}
}
This same function is been repeated(kind of not clean but still works) in each of the activity for tag detection and presence check & based on that read/write data to the Tag.
Here comes my problem,
Preconditions :
Tag in my application(product) is at a fixed location(sticked in a hardware) & is not usually taken out unless there is a tag change.
There are situations where Tag can be taken out in mostly ActivityB or ActivityC activity will be running, which required to repeat the same callback code in these activities.
Required:
- When switching from ActvityA-> ActivityB, Tag detection flow is not done(onNewIntent) or TAg is not taken out from proximity and tapped again. How will I write/read data to the tag?
ANFCManager,
class ANfcManager #Inject constructor(context: Context) {
private val mContext = context
private lateinit var nfcAdapter: NfcAdapter
private lateinit var mTag: Tag
private lateinit var iCodeTag: ICodeSlix2
private lateinit var icode: ICode
init {
val readPermission = ContextCompat.checkSelfPermission(
mContext,
Manifest.permission.WRITE_EXTERNAL_STORAGE
) == PackageManager.PERMISSION_GRANTED
if (!readPermission) {
ActivityCompat.requestPermissions(
mContext as Activity,
arrayOf(Manifest.permission.WRITE_EXTERNAL_STORAGE), 113
)
}
/**
* initialize background thread for presence check every x seconds.
*/
val thread = HandlerThread("PresenceCheckThread")
thread.start()
mHandler = PresenceHandler(thread.looper)
}
fun enableForegroundDispatch(
activity: FragmentActivity, intent: PendingIntent,
filters: Array<IntentFilter>?, techLists: Array<Array<String>>?
) {
nfcAdapter.enableForegroundDispatch(activity, intent, filters, techLists)
}
fun disableForegroundDispatch(activity: Activity) {
nfcAdapter.disableForegroundDispatch(activity)
}
fun filterIntent(intent: Intent): Boolean {
val action = intent.action
if (NfcAdapter.ACTION_TECH_DISCOVERED == action
|| NfcAdapter.ACTION_TAG_DISCOVERED == action
|| NfcAdapter.ACTION_NDEF_DISCOVERED == action
) {
if (intent.hasExtra(NfcAdapter.EXTRA_TAG)) {
mTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG)!!
return if (discoverTag()) {
Toast.makeText(mContext, "Tag detected.", Toast.LENGTH_SHORT).show()
true
} else {
ignoreTag()
false
}
}
}
return false
}
/**
* discover the Tag family.
*/
fun discoverTag(): Boolean {
icode = getTag(mTag)
if (ICodeSlix2::class.java.isInstance(icode))
iCodeTag = icode as ICodeSlix2
return iCodeTag != null
}
fun checkNfcPowerStatus(): Boolean {
return checkNfcPowerStatus(mContext)
}
/**
* Check Nfc status
*/
private fun checkNfcPowerStatus(context: Context?): Boolean {
nfcAdapter = NfcAdapter.getDefaultAdapter(context)
var enabled = false
if (nfcAdapter != null) {
enabled = nfcAdapter.isEnabled
}
return enabled
}
fun writeUpdateBlocks() {
try {
iCodeTag.connect()
.
. // proprietary code
.
}catch (e: IOException) {
e.printStackTrace()
Log.e(TAG, "IOException: ", e)
} catch (e: SmartCardException) {
e.printStackTrace()
Log.e(TAG, "SmartCardException: ", e)
} catch (e: IllegalArgumentException) {
e.printStackTrace()
Log.e(TAG, "IllegalArgumentException: ", e)
} catch (e: IllegalStateException) {
e.printStackTrace()
Log.e(TAG, "IllegalArgumentException: ", e)
} catch (e: IndexOutOfBoundsException) {
e.printStackTrace()
Log.e(TAG, "IndexOutOfBoundsException: ", e)
} finally {
iCodeTag.close()
}
}

Required: - When switching from ActvityA-> ActivityB, Tag detection
flow is not done(onNewIntent) or TAg is not taken out from proximity
and tapped again. How will I write/read data to the tag?
So the Tag object is a Parcelable Object , just pass it from ActivityA to ActivityB, you don't need to re-discover it.
e.g. something like (sorry in Java not Kotlin)
ActivityA
Intent intent = new Intent(getActivity(), ActivityB.class);
intent.putExtra("TAG", mTag);
startActivity(intent);
The in ActivityB onCreate
Intent intent = getIntent();
mTag = intent.getParcelableExtra("TAG")
// Start doing stuff with the Tag just like if you got it via discovery
// ANfcManager might need a `setTag` method to set it without discovery.
// or allow a Tag be be passed in the ANfcManager constructor
Not that I would use enableForegroundDispatch for reading and especially writing to Tags as I found it too unreliable, I would recommend enableReaderMode but then you can still pass the Tag Object between activities.

It was quick to convert the Manager class as Singleton and rest all remain same.
BaseActivity,
fun initField() {
mNfcManager = ANfcManager.getInstance(this)
}
class ANfcManager private constructor(context: Context){
companion object : SingletonHolder<ANfcManager, Context>(::ANfcManager) {
val TAG = ANfcManager::class.java.simpleName
}
init{
mContext = context
.
.
.
}
}