Question

我决定在片段中创建自定义列表视图，但出现错误：

FragmentOne.kt：（41，53）：类型不匹配：推断的类型为FragmentOne 但是活动是预期的。

下面的代码。

FragmentOne.kt

class FragmentOne : Fragment() {
    val name = arrayOf(
        "First catch","Second catch","Third catch","Fourth catch"
    )
    val date = arrayOf(
        "01.01.2019", "02.02.2010", "03.03.2003", "04.04.2004"
    )
    val imgId = arrayOf(
        R.drawable.fish
    )
    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?

    ): View? {
        // Inflate the layout for this fragment




        return inflater.inflate(R.layout.screen1, container, false)

    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        val myListAdapter = MyListAdapterInFragment(this,name,date,imgId)
        ListViewInFragment.adapter = myListAdapter

        }
    }

MyListAdapterInFragment.kt

class MyListAdapterInFragment(private val context: Activity, private val title: Array<String>, private val date: Array<String>, private val imgid: Array<Int>)
    : ArrayAdapter<String>(context, R.layout.list_iteminfragment, title) {

    override fun getView(position: Int, view: View?, parent: ViewGroup): View {
        val inflater = context.layoutInflater
        val rowView = inflater.inflate(R.layout.list_iteminfragment, null, true)

        val titleText = rowView.findViewById(R.id.title) as TextView
        val imageView = rowView.findViewById(R.id.imageViewInFragment) as ImageView
        val subtitleText = rowView.findViewById(R.id.date) as TextView

        titleText.text = title[position]
        imageView.setImageResource(imgid[position])
        subtitleText.text = date[position]

        return rowView
    }
}

Answer 1

更改此：

val myListAdapter = MyListAdapterInFragment(this,name,date,imgId)

对此：

val myListAdapter = MyListAdapterInFragment(activity,name,date,imgId)

Answer 2

使用view.context代替this

val myListAdapter = MyListAdapterInFragment(view.context,name,date,imgId)

Answer 3

片段类不会在其层次结构中扩展 Context类，因此，我们无法通过它代替 context 。

不过，您可以通过两种方式将上下文带入片段。

使用父级 Activity （在其上扩展了 Fragment ）：在需要activity的地方键入context。 ->在您的情况下： val myListAdapter = MyListAdapterInFragment(activity,name,date,imgId)
使用inflater方法中收到的onCreateView()变量中的 context ：键入inflater.context ->在您的情况下：设置一个属性val mContext:Context。在onCreateView（）方法中为其分配值mContext = inflater.context。然后在适配器对象中将其用作 val myListAdapter = MyListAdapterInFragment(mContext,name,date,imgId)

在片段中创建自定义列表视图时出错。必需的活动，找到片段

3 个答案: