I am trying to persist a timestamp in my room database using the following TypeConverter:
class Converters {
#TypeConverter
fun fromTimestamp(value: Long?): Calendar? {
if(value == null) return null
val cal = GregorianCalendar()
cal.timeInMillis = value
return cal
}
#TypeConverter
fun toTimestamp(timestamp: Calendar?): Long? {
if(timestamp == null) return null
return timestamp.timeInMillis
}
}
Two of my Entities include the following column
:
#ColumnInfo(name = "timestamp")
val timestamp: Calendar?,
But I get a compilation error upon trying to build the project - I had no issues when using the Date TypeConverter example from the developer reference guide.
I am unable to see what the actual error is as I just get a bunch of databinding 'cannot find symbol' errors if there is something wrong with the code related to Room.
Use:
object Converters {
#TypeConverter
#JvmStatic
fun fromTimestamp(value: Long?): Calendar? = value?.let { value ->
GregorianCalendar().also { calendar ->
calendar.timeInMillis = value
}
}
#TypeConverter
#JvmStatic
fun toTimestamp(timestamp: Calendar?): Long? = timestamp?.timeInMillis
}
And
#TypeConverters(Converters::class)
abstract class AppDatabase : RoomDatabase() {
Related
I have a model with default values. My app gets the data from user through EditTexts and add them to Firebase Firestore. I hava an addData function (in AddAnalyzeActivity) and savefunction (in AddAnalyzeViewModel) for this operation. I'm getting EditText entries in AddAnalyzeActivity and adding them to my model but on this step ı want to add document id to my model but I can't access the documentIds properly in AddAnalyzeActivity. I can only access them with a forEach method when I try to retrieving the mentioned data with retrieveData function (in PairDetailVM) from Firestore but If I try to add document Ids in retrieveData method it only adds default value of documentId.
What I tried to:
Using #DocumentId annotation in my model.
Setting null default value of documentId in my model.
Getting a list of all documents' ids but can't match them with actual items.
Here is the screenShot for logic:
AnalyzeModel:
data class AnalyzeModel(
var concept: String?="",
var reason: String?="",
var result: String?="",
var rrRatio: Double?=0.0,
var tarih: Timestamp=Timestamp.now(),
var tradingViewUrl: String="",
var id : String="")
addData :
fun addData(view: View) {
val tarih = com.google.firebase.Timestamp.now()
val rr = rrText.text.toString()
var doubleRR = rr.toDoubleOrNull()
if (doubleRR == null) { doubleRR = 0.0 }
val analyzeDTO = AnalyzeModel(
conceptText.text.toString(),
reasonForText.text.toString(),
resultAddingText.text.toString(),
doubleRR,
tarih,
chartImage.text.toString()
)
viewModel.save(analyzeDTO)
val intent = Intent(this, PairDetailActivity::class.java)
startActivity(intent)
finish()
}
save :
fun save(data: AnalyzeModel) {
database.collection(dbCollection!!).document("Specified").collection("Pairs")
.document(chosenPair!!)
.collection("Analysis")
.add(data)
.addOnFailureListener { exception ->
exception.printStackTrace()
Toast.makeText(getApplication(), exception.localizedMessage, Toast.LENGTH_LONG).show()
}
}
retrieveData:
private fun retrieveData() {
val docRef = collectionRef.orderBy("tarih", Query.Direction.DESCENDING)
docRef.addSnapshotListener { value, error ->
try {
if (value != null && !value.isEmpty) {
val allAnalysis= ArrayList<AnalyzeModel>()
val documents = value.documents
documents.forEach {
val analyze = it.toObject(AnalyzeModel::class.java)
if (analyze!=null){
allAnalysis.add(analyze)
}
}
list.value = allAnalysis
} else if (error != null) {
Toast.makeText(Application(), error.localizedMessage, Toast.LENGTH_LONG).show()
}
} catch (e: Exception) {
e.printStackTrace()
}
}
}
If you want to save the document ID into the document itself, consider separating the creation of the new DocumentReference from writing to it, by using set instead of add.
fun save(data: AnalyzeModel) {
val newRef = database.collection(dbCollection!!).document("Specified").collection("Pairs")
.document(chosenPair!!)
.collection("Analysis")
.document() // 👈 generates a new reference with a unique ID
data.id = newRef.id // 👈 set the ID into your object
newRef.set(data) // 👈 writes the data to the new reference
.addOnFailureListener { exception ->
exception.printStackTrace()
Toast.makeText(getApplication(), exception.localizedMessage, Toast.LENGTH_LONG).show()
}
}
Also see the second snippet in the documentation on adding a document
I am recently working with Flow in my retrofit's repository.
Sealed class for Result
enum class ApiStatus{
SUCCESS,
ERROR,
LOADING
}
sealed class ApiResult <out T> (val status: ApiStatus, val data: T?, val message:String?) {
data class Success<out R>(val _data: R?): ApiResult<R>(
status = ApiStatus.SUCCESS,
data = _data,
message = null
)
data class Error(val exception: String): ApiResult<Nothing>(
status = ApiStatus.ERROR,
data = null,
message = exception
)
data class Loading<out R>(val _data: R?, val isLoading: Boolean): ApiResult<R>(
status = ApiStatus.LOADING,
data = _data,
message = null
)
}
Example repository call for 3 state - Loading, Error, Success
fun googleDisconnect() = flow {
emit(ApiResult.Loading(null, true))
val call = userDataSource.self("v4").googleDisconnect()
if(call.isSuccessful) {
emit(ApiResult.Success(call.body()))
} else {
emit(ApiResult.Error("Google Disconnect Failed"))
}
}
However, I have multiple network call with different function in my repository. Is there any idea to write a generic function for these flow so that these flow can be emitted to the flow builder?
My attempt but problem is How can I pass suspend function into the function?
Finally I got myself the answer. I wonder if this will helps but I will post out my answer.
fun <T> toResultFlow(call: suspend () -> Response<T>?) : Flow<ApiResult<T>?> {
return flow {
emit(ApiResult.Loading())
val c = call() <-- have to initialize the call method first
c?.let {
try{
if(c.isSuccessful) {
c.body()?.let {
emit(ApiResult.Success(it))
}
} else {
c.errorBody()?.let {
val error = it.string()
it.close()
emit(ApiResult.Error(error))
}
}
}catch (e: Exception) {
emit(ApiResult.Error(e.toString()))
}
}
}.flowOn(Dispatchers.IO)
}
Then, pass in your suspend function as lambda
fun googleDisconnect() = toResultFlow {
userDataSource.self("v4").googleDisconnect()
}
Finally, the toResultFlow will be return Flow<ApiResult> and T is your preferred datatype! Volla!
I am able to open the database from within the main app activity using the following code, but once it's wrapped into a singleton object, it keeps throwing a null-object error:
object CommonClass {
fun openSQLDatabase(): SQLiteDatabase? {
var dbase: SQLiteDatabase? = null
try {
dbase = openOrCreateDatabase(
"dbfile.sqlite",
Context.MODE_PRIVATE, null
)
} catch (e: SQLException) {
println(e.message)
}
return dbase
}
}
I'm assuming that the main AppCompatActivity should be passing its context to the object in some way, but I've not been able to find a working model.
to Swayangjit
Android Studio highlights the Context.MODE_PRIVATE parameter and flags it as:
Type mismatch.
Required: SQLiteDatabase.CursorFactory?
Found: Int
But when I implement the AppCompatActivity to the singleton object and pass the Context.MODE_PRIVATE from the main activity, it runs but throws this error:
java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.sqlite.SQLiteDatabase android.content.Context.openOrCreateDatabase(java.lang.String, int, android.database.sqlite.SQLiteDatabase$CursorFactory)' on a null object reference
I believe the following will work :
object CommonClass {
fun openSQLDatabase(context: Context): SQLiteDatabase? {
var dbase: SQLiteDatabase? = null
if (dbase == null) {
try {
dbase = openOrCreateDatabase(context.getDatabasePath("dbfile.sqlite"), null)
} catch (e: SQLException) {
println(e.message)
}
}
return dbase
}
}
Note this assumes that you want the database in the default location i.e. data/data/the_package_name/databases/dbfile.sqlite
You could invoke/call it using something like :-
val mydb = CommonClass.openSQLDatabase(this)
it works fine if i change lateinit var id: String in the Payment.kt and CartPayment.kt to var id: String? = "", but the problem is i want the id to be required, how can i achieve that ?
The Error:
java.lang.RuntimeException: Unable to create application: io.realm.exceptions.RealmMigrationNeededException: Migration is required due to the following errors:
- Property 'CartPayment.id' has been made required.
- Property 'Payment.id' has been made required.
Model :
open class Payment() : RealmObject() {
#PrimaryKey
lateinit var id: String
var typeValue: Int = 0
var statusValue: Int = 0
var value: Double = 0.0
var referenceNumber: String? = null
Note: Payment and CartPayment models are identical except for the class name
Migration.kt
class Migration : RealmMigration {
override fun migrate(realm: DynamicRealm, oldVersion: Long, newVersion: Long) {
var oldVersion = oldVersion
val schema = realm.schema
if (oldVersion == 0L) {
schema.create("Payment")
.addField("id", String::class.java, FieldAttribute.PRIMARY_KEY)
.addField("typeValue", Int::class.java)
.addField("statusValue", Int::class.java)
.addField("value", Double::class.java)
.addField("referenceNumber", String::class.java)
schema.get("Order")!!
.addRealmListField("payments", schema.get("Payment")!!)
oldVersion++
}
if (oldVersion == 1L) {
schema.create("CartPayment")
.addField("id", String::class.java, FieldAttribute.PRIMARY_KEY)
.addField("typeValue", Int::class.java)
.addField("statusValue", Int::class.java)
.addField("value", Double::class.java)
.addField("referenceNumber", String::class.java)
schema.get("Order")!!
.addField("cashPaymentAmount", Float::class.java)
.addField("change", Float::class.java)
oldVersion++
}
}
}
App.kt
class App: Application() {
override fun onCreate() {
super.onCreate()
Realm.init(this)
val realmConfig = RealmConfiguration.Builder()
.schemaVersion(2)
.migration(Migration())
.build()
Realm.getInstance(realmConfig)
Realm.setDefaultConfiguration(realmConfig)
Fresco.initialize(this)
}
}
.addField("id", String::class.java, FieldAttribute.PRIMARY_KEY, FieldAttribute.REQUIRED)
did the trick.
if you declare the variable to be lateinit, make sure to add FieldAttribute.REQUIRED.
Basically you are adding a new field "id" which is primary key (hence required key).
If you do not specify any value while initialisation (lateinit), how will realm migrate all the earlier records, which doesn't have an id, but is required after migration ? Hence the error.
Below solutions might work
Either pre-populate the id's (without using lateinit)
Transform your earlier records to have id's if they don't have
Check the official examples here
For me, it happened after I have done the Migration.
I have made a non-nullable object in Kotlin and on migration I was creating a nullable wrapper type like Double, Int, etc.
Just use
Double::class.java
instead of
Double::class.javaObjectType
So I have hundreds of fields in a couple of classes and I'd like to write some methods on them where they automatically println each field and its corresponding value
At the moment I have this:
inner class Version(val profile: Profile) {
#JvmField val MINOR_VERSION = glGetInteger(GL_MINOR_VERSION)
fun write(file: File? = null) {
//file.printWriter().use { out -> out.pri }
this::class.java.fields.forEach {
println(it.isAccessible)
println(it.getInt(it)) }
}
}
But this is what I get:
false
Exception in thread "main" java.lang.IllegalArgumentException: Can not set final int field uno.caps.Caps$Version.MINOR_VERSION to java.lang.reflect.Field
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:167)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:171)
at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java:58)
at sun.reflect.UnsafeQualifiedIntegerFieldAccessorImpl.getInt(UnsafeQualifiedIntegerFieldAccessorImpl.java:58)
Any idea?
Instead of using Java fields and Java reflection code, you can also use Kotlin properties and Kotlin reflection classes:
class Reflector {
val Foo = 1;
fun printFields() {
this::class.memberProperties.forEach {
if (it.visibility == KVisibility.PUBLIC) {
println(it.name)
println(it.getter.call(this))
}
}
}
}
It seems that you are passing the Field variable it as a parameter getInt whereas the parameter should be the object the field belongs to this:
From the Javadoc for Field.getInt(Object obj):
obj - the object to extract the int value from
Perhaps this is what you meant to do:
class Reflector {
#JvmField val Foo = 1;
fun printFields() {
this.javaClass.fields.forEach {
println(it.isAccessible)
println(it.getInt(this))
}
}
}
fun main(args : Array<String>) {
Reflector().printFields()
}