Kotlin简单写一个listview的Demo

Kotlin已经是谷歌推荐的安卓语言了，最近也在学习，做了一个listview的Demo

代码如下：

class MainActivity : AppCompatActivity() ,AdapterView.OnItemClickListener{
    override fun onItemClick(parent: AdapterView<*>?, view: View?, position: Int, id: Long) {
        Toast.makeText(this,"点击了$position",Toast.LENGTH_SHORT).show()
    }


    val datas :ArrayList = arrayListOf("第一","第二","第三","第四","第五")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        var adapter: DemoAdapter= DemoAdapter(datas,this)
        lv_demo.adapter =adapter
        lv_demo.onItemClickListener=this
        lv_demo.dividerHeight=2
    }

    
}

Adapter中的代码如下：

class DemoAdapter(var mList: List, var context: Context) : BaseAdapter() {

    override fun getView(position: Int, convertView: View?, parent: ViewGroup?): View {
        var holder:ViewHolder
        var view :View
        if (convertView==null){
            holder= ViewHolder()
            view=LayoutInflater.from(context).inflate(R.layout.item_deme,null, false)
            holder.textView=view.findViewById(R.id.item_tv) as TextView
            view.tag=holder
        }else{
            view = convertView
            //获取tag并强转
            holder = view.tag as ViewHolder
        }
        holder.textView.text=mList[position]

        return view
    }

    override fun getItem(position: Int): Any {

        return mList[position]
    }

    override fun getItemId(position: Int): Long {

        return position .toLong()
    }

    override fun getCount(): Int {
        return mList.size
    }
    class  ViewHolder{
        lateinit var textView: TextView

    }

}

这样简单的listview的代码就写好了，运行效果如下：