这是我第一次构建android应用程序。但是,当我在虚拟设备上运行该应用程序时,它停止工作并不断崩溃。该错误说明了有关空指针异常的信息。这是我第一次使用Kotlin,并且用Java编写代码并更改为Kotlin。
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_add_sales)
val date: EditText? = null
val changeDate: CheckBox? = null
val yes: RadioButton? = null
val no: RadioButton? = null
date!!.setText("15-11-2017")
date.isEnabled = false
val button2 = findViewById<View>(R.id.btnSubmit) as Button
button2.setOnClickListener {
var name = findViewById<View>(R.id.name) as EditText
var cost = findViewById<View>(R.id.cost) as EditText
val itemcost = Integer.parseInt(cost!!.text.toString())
var price = findViewById<View>(R.id.price) as EditText
val itemprice = Integer.parseInt(price!!.text.toString())
var qty = findViewById<View>(R.id.quantity) as EditText
var chgDate = false
var discount = false
val toast = Toast(applicationContext)
if (itemprice < itemcost) {
price!!.error = "Selling price cannot be lower than item price!"
} else {
if (changeDate!!.isChecked) {
chgDate = true
date.isEnabled = true
}
if (yes!!.isChecked) {
discount = true
}
}
Toast.makeText(this@AddSales, "Item Name: " + name!!.text + "\n" + "Cost: " + cost!!.text + "\n" + "Item Price: " + price!!.text + "\n" + "Quantity: " + qty!!.text + "Date: " + date + "Staff Discount: " + discount, Toast.LENGTH_SHORT).show()
}
}
错误是:
最佳答案
似乎您忘记了初始化date
editText。为什么不尝试Kotlin Android Extension plugin。通过使用此插件,您无需初始化 View ,而是可以使用其ID直接使用它们。对于您的情况:
只需添加导入
import kotlinx.android.synthetic.main.activity_add_sales.*
然后,您现在可以删除以下内容:
val date: EditText? = null
val changeDate: CheckBox? = null
val yes: RadioButton? = null
val no: RadioButton? = null
您可以通过其ID访问它们。喜欢
date.setText("15-11-2017")
关于android - 致命异常:主要KotlinNullPointerException,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/47344537/