我正在嘗試使用片段來避免過多的活動給我的應用程式帶來負擔。在我的 mainActivity 中有一個地圖，然后我創建了一個片段，其中有 editText 欄位，我想使用這些 editText 插入要用作引數的數字，以傳遞給在另一個名為 navFun 的類中創建的函式。我試圖撰寫代碼，但我不明白為什么在使用 findViewById 時會出現這些錯誤：
Unresolved reference: findViewById
這是我的片段代碼
package uk.co.lorenzopulcinelli.navigationdrawer
import android.os.Bundle
import android.util.Log
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Button
import android.widget.EditText
import android.widget.Toast
import java.lang.Exception
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private const val ARG_PARAM1 = "param1"
private const val ARG_PARAM2 = "param2"
/**
* A simple [Fragment] subclass.
* Use the [CreatePathFragment.newInstance] factory method to
* create an instance of this fragment.
*/
class CreatePathFragment : Fragment() {
// TODO: Rename and change types of parameters
private var param1: String? = null
private var param2: String? = null
val mainActivity: MainActivity = MainActivity()
val navFun: NavFun = NavFun(mainActivity.context, mainActivity.mapView)
private lateinit var editTextLatitudineP1: EditText
private lateinit var editTextLongitudineP1: EditText
private lateinit var editTextLatitudineP2: EditText
private lateinit var editTextLongitudineP2: EditText
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
arguments?.let {
param1 = it.getString(ARG_PARAM1)
param2 = it.getString(ARG_PARAM2)
}
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// create path between editText points
editTextLatitudineP1 = findViewById<EditText>(R.id.editTextLatitudineP1)
editTextLongitudineP1 = findViewById<EditText>(R.id.editTextLongitudineP1)
editTextLatitudineP2 = findViewById<EditText>(R.id.editTextLatitudineP2)
editTextLongitudineP2 = findViewById<EditText>(R.id.editTextLongitudineP2)
val b = findViewById<Button>(R.id.location)
b.setOnClickListener{
try {
Log.d("Path", "Clicked")
val p1lati: Double = editTextLatitudineP1.text.toString().toDouble()
val p1long: Double = editTextLongitudineP1.text.toString().toDouble()
val p2lati: Double = editTextLatitudineP2.text.toString().toDouble()
val p2long: Double = editTextLongitudineP2.text.toString().toDouble()
println("latitudine: $p2lati, longitudine: $p2long")
navFun.routePath(p1lati, p1long, p2lati, p2long)
mainActivity.mapView.invalidate()
} catch (e: Exception) {
Toast.makeText(context, "Error when entering coordinates", Toast.LENGTH_SHORT).show()
}
}
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_create_path, container, false)
}
companion object {
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment CreatePathFragment.
*/
// TODO: Rename and change types and number of parameters
@JvmStatic
fun newInstance(param1: String, param2: String) =
CreatePathFragment().apply {
arguments = Bundle().apply {
putString(ARG_PARAM1, param1)
putString(ARG_PARAM2, param2)
}
}
}
}
這是我的片段 xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/white"
tools:context=".CreatePathFragment"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/crea_percorso"
android:textColor="@color/black"
android:textSize="40sp"
android:textStyle="bold" />
<TextView
android:id="@ id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/inserisci_le_coordinate_dei_punti_tra_cui_vuoi_creare_un_percorso" />
<TextView
android:id="@ id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/latitudine_punto_di_partenza" />
<EditText
android:id="@ id/editTextLatitudineP1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:ems="10"
android:hint="@string/latitudine_p1"
android:inputType="numberSigned|numberDecimal" />
<TextView
android:id="@ id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/longitudine_punto_di_partenza" />
<EditText
android:id="@ id/editTextLongitudineP1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:ems="10"
android:hint="@string/longitudine_p1"
android:inputType="numberSigned|numberDecimal" />
<TextView
android:id="@ id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/latitudine_punto_di_arrivo" />
<EditText
android:id="@ id/editTextLatitudineP2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:ems="10"
android:hint="@string/latitudine_p2"
android:inputType="numberSigned|numberDecimal" />
<TextView
android:id="@ id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/longitudine_punto_di_arrivo" />
<EditText
android:id="@ id/editTextLongitudineP2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:ems="10"
android:hint="@string/longitudine_p2"
android:inputType="numberSigned|numberDecimal" />
<Button
android:id="@ id/location"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/crea_percorso"
/>
</LinearLayout>
uj5u.com熱心網友回復：
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_create_path, container, false)
// create path between editText points
editTextLatitudineP1 = view.findViewById<EditText>(R.id.editTextLatitudineP1)
editTextLongitudineP1 = view.findViewById<EditText>(R.id.editTextLongitudineP1)
editTextLatitudineP2 = view.findViewById<EditText>(R.id.editTextLatitudineP2)
editTextLongitudineP2 = view.findViewById<EditText>(R.id.editTextLongitudineP2)
val b = findViewById<Button>(R.id.location)
b.setOnClickListener{
try {
Log.d("Path", "Clicked")
val p1lati: Double = editTextLatitudineP1.text.toString().toDouble()
val p1long: Double = editTextLongitudineP1.text.toString().toDouble()
val p2lati: Double = editTextLatitudineP2.text.toString().toDouble()
val p2long: Double = editTextLongitudineP2.text.toString().toDouble()
println("latitudine: $p2lati, longitudine: $p2long")
navFun.routePath(p1lati, p1long, p2lati, p2long)
mainActivity.mapView.invalidate()
} catch (e: Exception) {
Toast.makeText(context, "Error when entering coordinates", Toast.LENGTH_SHORT).show()
}
}
// Inflate the layout for this fragment
return view
}
您必須首先創建您的視圖，然后在該視圖上呼叫 findViewById。
uj5u.com熱心網友回復：
findViewById 在 onCreateView 中不起作用，因為此時正在創建 UI，因此尚未初始化視圖。
嘗試鏈接 onViewCreated 內的視圖。<-- 你可以使用 ctrl O 匯入它
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
editTextLatitudineP1 = findViewById<EditText>(R.id.editTextLatitudineP1)
//.....the rest of your code
}
轉載請註明出處，本文鏈接：https://www.uj5u.com/qiye/507362.html
標籤：安卓 科特林 安卓片段 findviewbyid