我们通过将其转换为Kotlin,创建了一个自定义警报对话框,并在Java项目中使用它。下面是发布的错误信息 java.lang.IllegalStateException: findViewById(R.id.btnYES) must not be null
我们无法找到错误源!我们查看了许多帖子并尝试了一些方法,但没有结果。Activity结构如下:PageTwoActivity有自己的XML文件和两个附加按钮。自定义对话框具有自己的xml文件 以下是PageTwoActivity代码。没有两个按钮用于PageTwoActivity 没有名称冲突
import android.app.Dialog
import android.content.Intent
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.EditText
import android.widget.Toast
class PageTwoActivity : AppCompatActivity() {
internal lateinit var btnBACK: Button
internal lateinit var btnDIALOG: Button
internal lateinit var btnYES: Button
internal lateinit var btnNO: Button
internal lateinit var etStudentName:EditText
var EnteredText: String = ""
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_page_two)
btnBACK = findViewById(R.id.btnBACK)
btnDIALOG = findViewById(R.id.btnDIALOG)
btnYES = findViewById(R.id.btnYES)
btnNO = findViewById(R.id.btnNO)
etStudentName = findViewById(R.id.etStudentName)
addListenerOnButtonBACK()
addListenerOnButtonDIALOG()
Toast.makeText(this@PageTwoActivity, "You are on Page Two",
Toast.LENGTH_LONG).show()
}// END onCreate
这是自定义对话框的代码
private fun doCustom() {
val openDialog = Dialog(this)
openDialog.setContentView(R.layout.custom_dialog)
//val btnYES = view!!.findViewById<Button>(R.id.btnYES)
//val btnNO = openDialog.findViewById(R.id.btnNO)
//val etStudentName = openDialog.findViewById(R.id.etStudentName)
openDialog.setCancelable(false)
btnYES.setOnClickListener(View.OnClickListener {
EnteredText = etStudentName.getText().toString().trim({ it <= ' ' })
if (EnteredText.isEmpty()) {
Toast.makeText(applicationContext, "Enter Your Name\n\n OR Click
DECLINE", Toast.LENGTH_LONG).show()
return@OnClickListener
}
Toast.makeText(applicationContext, "Registered $EnteredText",
Toast.LENGTH_SHORT).show()
openDialog.dismiss()
})
btnNO.setOnClickListener(View.OnClickListener {
EnteredText = ""
val intent = Intent(this@PageTwoActivity, MainActivity::class.java)
startActivity(intent)
openDialog.dismiss()
})
openDialog.show()
}
自定义对话框的 XML 文件代码。<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="400dp"
android:layout_height="200dp"
android:background="@color/color_lightGray">
<TextView
android:id="@+id/tvDAT"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="70dp"
android:layout_marginTop="30dp"
android:text="Enter First and Last Name"
android:textColor="@color/color_Black"
android:textSize="22sp"
android:textStyle="bold" />
<EditText
android:id="@+id/etStudentName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:layout_marginTop="80dp"
android:ems="14"
android:gravity="center"
android:inputType="textPersonName"
android:text=""
android:textColor="@color/color_Black"
android:textSize="20sp"
android:textStyle="bold" />
<Button
android:id="@+id/btnYES"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="250dp"
android:layout_marginTop="120dp"
android:background="@color/color_Transparent"
android:text="TAKE QUIZ"
android:textColor="@color/color_deepBlue"
android:textSize="22sp"
android:textStyle="bold" />
<Button
android:id="@+id/btnNO"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="22dp"
android:layout_marginTop="120dp"
android:background="@color/color_Transparent"
android:text="DECLINE"
android:textColor="@color/color_deepBlue"
android:textSize="22sp"
android:textStyle="bold" />
</RelativeLayout>
所以问题是如何解决这个错误?我们应该膨胀自定义对话框xml吗?正如您所看到的,我们尝试将声明移动到doCustom函数中查找id //val btnYES = view!!.findViewById(R.id.btnYES) 这个链接提供了建议,但我们不知道从哪里开始 LINK