KotlinでViewDataBindingをｼｭｯとinflateするやつ

RecyclerViewなどでViewDataBindingを使う時に次のように書くのめんどくさくて。

class ViewHolder(val binding:ListItemCommentBinding)
: RecyclerView.ViewHolder(binding.root)
override fun onCreateViewHolder(parent: ViewGroup, type: Int) = 
  ViewHolder(ListItemCommentBinding
    .inflate(LayoutInflater.from(parent.context), parent, false))

こういう感じにViewGroupに関数生やすと、

ViewExtensions.kt

inline fun <reified T : ViewDataBinding> 
  ViewGroup.inflateBinding(): T {
    return T::class.java
            .getDeclaredMethod(
              "inflate",
              LayoutInflater::class.java, 
              ViewGroup::class.java, 
              Boolean::class.javaPrimitiveType
            )
            .invoke(null, LayoutInflater.from(context), this, false) as T
}

良さそう。

override fun onCreateViewHolder(parent: ViewGroup, type: Int) =
  ViewHolder(parent.inflateBinding()) 

ViewHolderが複数種類のViewDataBindingを取り扱う場合は型引数が要る。

override fun onCreateViewHolder(parent: ViewGroup, type: Int) =
  ViewHolder(parent.inflateBinding<ListItemCommentBinding>()) 

追記 2017/05/23

proguardで死ぬので、使うときは次の設定が必要になります。ひょえ〜

-keep class * extends android.databinding.ViewDataBinding {
    public static ** inflate(android.view.LayoutInflater, android.view.ViewGroup, boolean);
}