kotlin

问题 I'm using androidx.emoji.widget.EmojiEditText. I want to force user to enter only emojis here. And limit him to max 3 emojis. How can I do something like this? I tried to use external emoji keyboard that cancels the soft keyboard and shows up but didn't work properly. <androidx.emoji.widget.EmojiEditText android:id="@+id/etEmoji" android:layout_width="match_parent" android:layout_height="30dp" android:layout_margin="10dp" android:hint="Enter Emoji" android:inputType="textShortMessage" android

问题 I'm using androidx.emoji.widget.EmojiEditText. I want to force user to enter only emojis here. And limit him to max 3 emojis. How can I do something like this? I tried to use external emoji keyboard that cancels the soft keyboard and shows up but didn't work properly. <androidx.emoji.widget.EmojiEditText android:id="@+id/etEmoji" android:layout_width="match_parent" android:layout_height="30dp" android:layout_margin="10dp" android:hint="Enter Emoji" android:inputType="textShortMessage" android

问题 Here is the scenario of what I am trying to do: I am creating a RecyclerView that can add or remove one or more child item/fragment/view that has EditText(s) but.... Here is my problem: Whenever I scroll down in my RecyclerView, its items' value resets. I think the problem here is that the RecyclerView Adapter cannot bind or hold the values but I don't know where exactly is the problem in my code. class StocksAdapter() : RecyclerView.Adapter<ViewHolder>() { class StockFragmentHolder :

问题 Here is the scenario of what I am trying to do: I am creating a RecyclerView that can add or remove one or more child item/fragment/view that has EditText(s) but.... Here is my problem: Whenever I scroll down in my RecyclerView, its items' value resets. I think the problem here is that the RecyclerView Adapter cannot bind or hold the values but I don't know where exactly is the problem in my code. class StocksAdapter() : RecyclerView.Adapter<ViewHolder>() { class StockFragmentHolder :

问题 I'm using the Groupie library for showing expandable items and my issue is that instead of the items retrieved through an api call being shown under each of their parent expandable header, they're all shown together under the last item on the list. I would like to have this: Header 1 Child header 1 Child header 1 Child header 1 Header 2 Child header 2 Child header 2 I have this instead: Header 1 header 2 Child header 1 Child header 1 Child header 1 Child header 2 Child header 2 This is my

问题 Is Kotlin ?.let thread-safe? Let's say a variable can be changed in different thread. Is using a?.let { /* */ } thread-safe? If it's equal to if (a != null) { block() } can it happen that in if it's not null and in block it's already null? 回答1: a?.let { block() } is indeed equivalent to if (a != null) block() . This also means that if a is a mutable variable, then: a might be reassigned after the null check and hold a null value when block() is executed; All concurrency-related effects are in

问题 I was reading about reasons why kotlin does not have wildcards (https://kotlinlang.org/docs/reference/generics.html). It all came to the declaration-site variance. We have <in T> and <out T> constructions which should replace wildcards. I think I understood how <out T> works but I have troubles with <in T> . So in java we could write something like this: public List<? extends Number> list1; public List<? super String> list2; First case after initialization becomes read only list (though not

问题 I'm working on an app where I have a list with recyclerview and I want to add a divider for items. I have created the ItemDividerDecorator class and xml layout file but I'm not connecting to recycler view. I know how to do in java, something like this: recyclerView.addItemDecoration( new DividerItemDecoration(ContextCompat.getDrawable(getApplicationContext(), R.drawable.item_separator))); but how can I do in Kotlin, I also tried to convert it in Android Studio but shows me a couples of errors

问题 I'm working on an app where I have a list with recyclerview and I want to add a divider for items. I have created the ItemDividerDecorator class and xml layout file but I'm not connecting to recycler view. I know how to do in java, something like this: recyclerView.addItemDecoration( new DividerItemDecoration(ContextCompat.getDrawable(getApplicationContext(), R.drawable.item_separator))); but how can I do in Kotlin, I also tried to convert it in Android Studio but shows me a couples of errors

问题 I'm working on an app where I have a list with recyclerview and I want to add a divider for items. I have created the ItemDividerDecorator class and xml layout file but I'm not connecting to recycler view. I know how to do in java, something like this: recyclerView.addItemDecoration( new DividerItemDecoration(ContextCompat.getDrawable(getApplicationContext(), R.drawable.item_separator))); but how can I do in Kotlin, I also tried to convert it in Android Studio but shows me a couples of errors