Adapter 或 ViewHolder 中的 Kotlin 合成 [英] Kotlin synthetic in Adapter or ViewHolder

问题描述

我是 kotlin 新手.我发现并尝试在我的 Activity 类中使用合成方法而不是烦人的方法 findViewById，但我发现如果我们想调用 View 上的合成属性(有用在适配器类中)，我们还应该导入 kotlinx.android.synthetic.main.view.*."但我无法弄清楚它究竟是如何工作的?有例子吗?

I am new in kotlin. I have found and tried to use synthetic method instead of annoying method findViewById in my Activity class, but I have found "If we want to call the synthetic properties on View (useful in adapter classes), we should also import kotlinx.android.synthetic.main.view.*." But I can't figure out how it exactly works? Is there any examples?

推荐答案

来自 https://github 的简单示例.com/antoniolg/Kotlin-for-Android-Developers

import kotlinx.android.synthetic.item_forecast.view.*

class ForecastListAdapter() : RecyclerView.Adapter<ForecastListAdapter.ViewHolder>() {

    class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {

        fun bindForecast(forecast: Forecast) {
            itemView.date.text = forecast.date.toDateString()
        }
    }
}

不用写

val view = itemView.findViewById(R.id.date) as TextView
view.text = forecast.date.toDateString()

就

itemView.date.text = forecast.date.toDateString()

简单有效！

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