kotlin

问题 I want to use vararg with generics with different types of each arguments what I've already tried: class GeneralSpecification<T> { fun <P> ifNotNullCreateSpec(vararg propToCreateFun: Pair<P?, (P) -> Specification<T>>): List<Specification<T>> = propToCreateFun.mapNotNull { (prop, funCreateSpec) -> prop?.let(funCreateSpec) } ... } but I can't use this like: ifNotNullCreateSpec("asdf" to ::createStringSpec, 5 to ::createIntSpec) (different types in vararg pairs) How can I use vararg with

问题 I know how to pass times as the first parameter of repeat function: repeat(3) { println("This will print 3 times") } But I checked Kotlin documentation, it shows there's another parameter action to use(see kotlin doc): inline fun repeat(times: Int, action: (Int) -> Unit) I tried this code but failed with the error Expecting ')' : repeat(3, 2 -> anotherFun()) { println("This will show 2 times?") } fun anotherFun() { println("head into the 2nd time and print this out.") } I know I have got the

问题 In my MainActivity I have a viewpager2 with Tablayout with 5 tabs. The swipe there is working fine. But in one of the 5 tabs I again have a viewpager2 with a tablayout of 3 tabs. In the inner viewpager2 (which is inside a fragment) the swipe isnt working at all and I don't understand why. The outer viewpager2 is inside a activity while the inner viewpager2 is in the fragment Viewpager2 inside fragment , swipe not working : class FreelancerMyProjectsFragment : Fragment() { lateinit var binding

问题 How is @Named used with @BindsInstance? I have the this component interface AppComponent : AndroidInjector<MyApplication>{ @Component.Builder abstract class Builder : AndroidInjector.Builder<MyApplication>() { @BindsInstance abstract fun preferenceName( @Named("PreferenceName") name : String ) : Builder } } and trying to inject in MyApplication @Inject @Named("PreferenceName") lateinit var prefName : String But it fails with MissingBinding for String. I could resolve this with a module

问题 I am facing an issue while implementing MultiBinding using dagger 2.2. I am using dagger with MVVM architecture. I have injected the ViewModelProvideFactory constructor and binds the dependency from module. I have followed the tutorial of Mitch from youtube https://www.youtube.com/watch?v=DToD1W9WdsE&list=PLgCYzUzKIBE8AOAspC3DHoBNZIBHbIOsC&index=13 I have searched on these links for the solutions but still facing the same issue. Dagger2: ViewModel cannot be provided without an @Provides

问题 I'm just exploring kotlin collection and I observed one important behavior. val sports = listOf<Sports>( Sports("cricket", "7"), Sports("gilli", "10"), Sports("lagori", "8"), Sports("goli", "6"), Sports("dabba", "4") ) sports.sortedBy { it.rating } // sortedByDescending is to sort in descending .forEach({ println("${it.name} ${it.rating}") }) } class Sports(name: String, rating: String) { var name: String = name var rating: String = rating } above I can only get sortedBy method i.e which

问题 I'm just exploring kotlin collection and I observed one important behavior. val sports = listOf<Sports>( Sports("cricket", "7"), Sports("gilli", "10"), Sports("lagori", "8"), Sports("goli", "6"), Sports("dabba", "4") ) sports.sortedBy { it.rating } // sortedByDescending is to sort in descending .forEach({ println("${it.name} ${it.rating}") }) } class Sports(name: String, rating: String) { var name: String = name var rating: String = rating } above I can only get sortedBy method i.e which

问题 I'm creating a list of values, in a context where it so happens that, though the values are being added one at a time, the eventual number is known in advance. This is in a function that will be called many times, so the faster it runs, the better. In Java, I would use the ArrayList constructor that specifies an initial capacity, because in theory this makes it slightly faster because it avoids resizing. In Kotlin, one normally uses mutableListOf(), but this does not allow an initial capacity

问题 I've created this two extensions in Kotlin to Encrypt/Decrypt strings: fun String.encrypt(seed : String): String { val keyGenerator = KeyGenerator.getInstance("AES") val secureRandom = SecureRandom.getInstance("SHA1PRNG") secureRandom.setSeed(seed.toByteArray()) keyGenerator.init(128, secureRandom) val skey = keyGenerator.generateKey() val rawKey : ByteArray = skey.encoded val skeySpec = SecretKeySpec(rawKey, "AES") val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding") cipher.init(Cipher

问题 I'm having trouble creating a unit test without needing robolectric. I am using AndroidThreeTen.init(this) in my code and when I run my test if I disable robolectric I get an error: org.threeten.bp.zone.ZoneRulesException: No time-zone data files registered and if I leave it enabled I get this: [Robolectric] com.mycomp.,yapp.utilities.log.LogTest.on Calling function w it returns an Int: sdk=28; resources=BINARY I have tried using testImplementation ‘com.jakewharton.threetenabp:threetenabp:1.1