RecyclerView items using ConstraintLayout are not filling the entire width of the screen even though-CodePudding

I am attempting to set up a recycler view, with the elements being displayed by it using a ConstraintLayout. I used the Preview from Android Studio designer

Actual result

Actual result on emulated Pixel 5 running API 30/Android 11

CodePudding user response：

Your code here:

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecipeViewHolder {
    return RecipeViewHolder(
        RecipeListEntryBinding.inflate(
            LayoutInflater.from(
                parent.context
            )
        )
    )
}

does not inflate the view in the context of the parent view, so some layout parameters will not be treated as you expect. In this case, it can't have a width of match_parent if it doesn't know who its parent is. Change it to:

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecipeViewHolder {
    return RecipeViewHolder(
        RecipeListEntryBinding.inflate(
            LayoutInflater.from(
                parent.context
            ),
            parent,
            false
        )
    )
}

Also, a tip. You don't need to create a companion object just to hold your DiffCallback. And you don't need a property to hold an object either. For cleaner code, instead of

companion object {
    private val DiffCallback = object : DiffUtil.ItemCallback<Recipe>() {
        //...
    }
}

you could put

private object DiffCallback: DiffUtil.ItemCallback<Recipe>() {
    //...
}