kotlin

问题 When I try to run this code: fun main() { val input: String = readLine() val outputs = input.toCharArray() for (i in 0 until input.length) { print("${outputs[i]}${outputs[i]}") } } I get this Error:(2, 25) Kotlin: Type mismatch: inferred type is String? but String was expected. How do I fix that? 回答1: The readLine() function returns a String? (nullable String). Return the line read or null if the input stream is redirected to a file and the end of file has been reached. There is no end of

问题 When I try to run this code: fun main() { val input: String = readLine() val outputs = input.toCharArray() for (i in 0 until input.length) { print("${outputs[i]}${outputs[i]}") } } I get this Error:(2, 25) Kotlin: Type mismatch: inferred type is String? but String was expected. How do I fix that? 回答1: The readLine() function returns a String? (nullable String). Return the line read or null if the input stream is redirected to a file and the end of file has been reached. There is no end of

问题 When I try to run this code: fun main() { val input: String = readLine() val outputs = input.toCharArray() for (i in 0 until input.length) { print("${outputs[i]}${outputs[i]}") } } I get this Error:(2, 25) Kotlin: Type mismatch: inferred type is String? but String was expected. How do I fix that? 回答1: The readLine() function returns a String? (nullable String). Return the line read or null if the input stream is redirected to a file and the end of file has been reached. There is no end of

问题 i am using kotlin + springboot to build my web application. i want to create a tool class ,so i coded like above: @Service object XXXUtil{ @Autowired lateinit var restTemplate: RestTemplate @Autowired lateinit var objectMapper: ObjectMapper ... } but after i started the application, resTemplate cannot be injected. kotlin.UninitializedPropertyAccessException: lateinit property restTemplate has not been initialized is it because that object declaration does not allow injection or i code in a

问题 i am using kotlin + springboot to build my web application. i want to create a tool class ,so i coded like above: @Service object XXXUtil{ @Autowired lateinit var restTemplate: RestTemplate @Autowired lateinit var objectMapper: ObjectMapper ... } but after i started the application, resTemplate cannot be injected. kotlin.UninitializedPropertyAccessException: lateinit property restTemplate has not been initialized is it because that object declaration does not allow injection or i code in a

问题 I have found this question and the solution was this code : <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <solid android:color="#ffffff" /> <corners android:bottomLeftRadius="8dp" android:bottomRightRadius="8dp" android:topLeftRadius="8dp" android:topRightRadius="8dp" /> </shape> This code doesn't work on my PC (no rounded corners). And you ? There has been changes ? EDIT 1: I have an error when I build the project : AAPT: error: XML or text

问题 I have found this question and the solution was this code : <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <solid android:color="#ffffff" /> <corners android:bottomLeftRadius="8dp" android:bottomRightRadius="8dp" android:topLeftRadius="8dp" android:topRightRadius="8dp" /> </shape> This code doesn't work on my PC (no rounded corners). And you ? There has been changes ? EDIT 1: I have an error when I build the project : AAPT: error: XML or text

问题 I'm running an androidTest instrumentation test and I have a method that returns LiveData from a DAO object using Room. I'm calling the method like so: val animal = roomDatabase.animalsDao().getAnimal(1) animal.observeForever(mMockObserver) assertNotNull(animal.value) I used Mockito to mock the observer: @Mock private lateinit var mMockObserver = Observer<Animal> This should return an instance of LiveData containing the Animal at id 1, but it's null. It's my understanding that in order for

问题 Description So basically i am building an android app in which i am using kotlin and which will behave as server.Whilst on the client side i am using python.I am using sockets for this purpose.I have to communicate using UDP.But i am unable to make connection to my android app.In python script sock.connect(('10.0.2.2', 6000)) i have also tried placing the emulator ip instead of localhost.I just want to send and receive simple messages. Another Issue: Python script just times out it does not

问题 Description So basically i am building an android app in which i am using kotlin and which will behave as server.Whilst on the client side i am using python.I am using sockets for this purpose.I have to communicate using UDP.But i am unable to make connection to my android app.In python script sock.connect(('10.0.2.2', 6000)) i have also tried placing the emulator ip instead of localhost.I just want to send and receive simple messages. Another Issue: Python script just times out it does not