kotlin

问题 I have a class with some attributes: class DonutBox { var glaze: Int = 0 var chocolate: Int = 0 var maple: Int = 0 var etc: Int = 0 } fun addDonuts() { val omNom = DonutBox() } How can I increment a random attribute of the instantiated class? For instance, if the randomly selected attribute is chocolate , then effectively: omNom.chocolate += 1 回答1: Because Kotlin's properties are statically declared, and you want to use them dynamically, most of the methods to do that will involve reflection,

问题 I successfully implemented a Navigation Drawer in my app, linking each item of the menu to a fragment. The destination fragment hides the DrawerToggle and displays the up button (i.e. the arrow icon), but for whatever reason, if I click on it, it opens the drawer and I can't go back to the previous fragment. I have to press the back button to do it. How can I change this behaviour? Is it possible to solve this without adding code in every fragment? What I use: Navigation Component One

问题 I've one LiveData named sortOrder and then I've another variable named myData that observes any change to sortOrder and populates data accordingly. class TestViewModel @ViewModelInject constructor() : ViewModel() { private val sortOrder = MutableLiveData<String>() val myData = sortOrder.map { Timber.d("Sort order changed to $it") "Sort order is $it" } init { sortOrder.value = "year" } } Observing in Activity class TestActivity : AppCompatActivity() { private val viewModel: TestViewModel by

问题 I've one LiveData named sortOrder and then I've another variable named myData that observes any change to sortOrder and populates data accordingly. class TestViewModel @ViewModelInject constructor() : ViewModel() { private val sortOrder = MutableLiveData<String>() val myData = sortOrder.map { Timber.d("Sort order changed to $it") "Sort order is $it" } init { sortOrder.value = "year" } } Observing in Activity class TestActivity : AppCompatActivity() { private val viewModel: TestViewModel by

问题 I'm trying to build a native in Windows. I'm not sure where to put the dependency for implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.5'. My current gradle file looks like this: buildscript { ext.kotlin_version = '1.3.72' repositories { mavenCentral() } dependencies { classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion") } } plugins { id 'org.jetbrains.kotlin.multiplatform' version '1.3.72' } dependencies { implementation 'org.jetbrains.kotlinx:kotlinx

问题 I am setting up a android app by Kotlin, and I want to get image score for arcore. On this page they say: Run arcoreimg eval-img to get a quality score between 0 and 100 for each image. And I just found a program for Linux, macOS, Windows to unzip the arcore-android-sdk-1.11.0 . I want to calculate arcore image score via my Android app. How can I calculate the image score if the arcore team doesn't support it? I found some posts that run the Windows program on Android, but It is 'How To Run

问题 I am setting up a android app by Kotlin, and I want to get image score for arcore. On this page they say: Run arcoreimg eval-img to get a quality score between 0 and 100 for each image. And I just found a program for Linux, macOS, Windows to unzip the arcore-android-sdk-1.11.0 . I want to calculate arcore image score via my Android app. How can I calculate the image score if the arcore team doesn't support it? I found some posts that run the Windows program on Android, but It is 'How To Run

问题 my android studio started working with kotlin and not java after the last update. I have a university project that I need to deliver soon and we only learned coding with java, can anyone please help me find a way to return it to java thanks a lot 回答1: If I understand your problem correctly, when you create new project you have to uncheck "Include Kotlin support" checkbox at the bottom of "Create new project" window. And remember that you can create java classes in Kotlin project. 回答2: If you

问题 I need only date from Calendar Instance not the time. Whenever i used calendar object it returns the date with time. val calendar = Calendar.getInstance() calendar.time. // Mon Nov 09 11:41:29 GMT 2020 I change this by using SimpleDateFormat SimpleDateFormat("dd/MM/yyyy").format(date) 09/09/2020 I am creating calendar so i have huge amount of data in list. I am adding data at specific date. So I am comparing dates with string date. My string date Format is look like this :- 20/05/2020 So

问题 I'm trying to implement a datepicker but I need to disable some days. For example, I do not want the user to pick Friday and Saturday. I read in other posts that I need to use this library, but I still do not know how it works and how to do it in Kotlin. Someone help me plz. 回答1: In the library documentation there is mentioned that how to use select able days and how to disable certain days. For both purpose you have to pass the array of days to the respective methods. For example if you want