android - ListView可以出现在“Activity ”中，但不能出现在“fragment ”中

ListView可以出现在Activity中，但不能出现在Fragment中。但是，我在Kotlin和Android Studio 3.0中使用了相同的代码吗？

这是我的片段代码:

class testFrag : Fragment() {
var adapter : mo3dAdapter?=null
var listOfMkabala = ArrayList<MeetingDetails>()


override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    return inflater!!.inflate(R.layout.fragment_test, container, false)


    listOfMkabala .add ( MeetingDetails(" nour1", "ahmed1" , "aya1"))
    listOfMkabala .add ( MeetingDetails(" nour2", "ahmed2" , "aya2"))
    listOfMkabala .add ( MeetingDetails(" nour3", "ahmed3" , "aya3"))
    listOfMkabala .add ( MeetingDetails(" nour4", "ahmed4" , "aya4"))
    listOfMkabala .add ( MeetingDetails(" nour5", "ahmed5" , "aya5"))
    listOfMkabala .add ( MeetingDetails(" nour6", "ahmed6" , "aya6"))


    adapter = mo3dAdapter (context  ,listOfMkabala)
    tv1.adapter = adapter

}


fun test ( view: View){

}

这是我的适配器:

inner class mo3dAdapter: BaseAdapter {
    var  listOfMkabaln= ArrayList<MeetingDetails>()
    var context:Context?=null
    constructor(context:Context, listOfMkabaln: ArrayList<MeetingDetails>):super(){
        this.listOfMkabaln=listOfMkabaln
        this.context=context
    }

    override fun getView(p0: Int, p1: View?, p2: ViewGroup?): View {
        val mo3d =  listOfMkabaln[p0]

        var inflator = context!!.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        var myView = inflator.inflate(R.layout.fragment_test, null)
        myView.text1.text = mo3d.name1!!
        myView.text2.text = mo3d.name2!!
        myView.text3.text = mo3d.name3!!

        return myView

    }

    override fun getItem(p0: Int): Any {
        return listOfMkabaln[p0]
    }

    override fun getItemId(p0: Int): Long {
        return p0.toLong()
    }

    override fun getCount(): Int {

        return  listOfMkabaln.size
    }

}

最佳答案

在初始化后，您应该制作一个return语句
onCreateView()。

您正在使用kotlin-android-extensions直接获取 View 。如果使用这种方式，则只有在创建 View 后才能获取LisView。

您的代码应如下所示。

override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
 return inflater!!.inflate(R.layout.fragment_test, container, false)
}

override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
    listOfMkabala .add ( MeetingDetails(" nour1", "ahmed1" , "aya1"))
    listOfMkabala .add ( MeetingDetails(" nour2", "ahmed2" , "aya2"))
    listOfMkabala .add ( MeetingDetails(" nour3", "ahmed3" , "aya3"))
    listOfMkabala .add ( MeetingDetails(" nour4", "ahmed4" , "aya4"))
    listOfMkabala .add ( MeetingDetails(" nour5", "ahmed5" , "aya5"))
    listOfMkabala .add ( MeetingDetails(" nour6", "ahmed6" , "aya6"))
    adapter = mo3dAdapter (context  ,listOfMkabala)
    tv1.adapter = adapter
}

onViewCreated()在创建 View 后运行。这样可以确保您的 View 已经创建。

您还为适配器传递了相同的布局。

在您的适配器代码中，将R.layout.fragment_test更改为模型布局。

var myView = inflator.inflate(R.layout.fragment_test, null)

希望能帮助到你:)