当我在
EditText
上调用addTextChangedListener(textWatcher)
并尝试运行应用程序时,当在该字段中输入内容时,应用程序会直接关闭。
我的启用按钮的方式不正确吗?class MainActivity : AppCompatActivity() {
lateinit var num1TextE: EditText
lateinit var resultText: TextView
lateinit var plusBtn: Button
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
num1TextE = findViewById(R.id.firstNum_TextE)
plusBtn = findViewById(R.id.plus_btn)
resultText = findViewById(R.id.result_TextV)
resultText.visibility = View.GONE
plusBtn.isClickable= false
plusBtn.isEnabled = false
num1TextE.addTextChangedListener(textWatcher)
plusBtn.setOnClickListener {
var num1 = num1TextE.text.toString().toInt()
var num2 = num2TextE.text.toString().toInt()
resultText.visibility = View.VISIBLE
resultText.text = "Result is ${num1 + num2}"
}
}
var textWatcher = object : TextWatcher {
override fun afterTextChanged(p0: Editable?) {
}
override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
}
override fun onTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
var test: String = num1TextE.text.toString()
if(! test.isEmpty()) {
plusBtn.isClickable = true
plusBtn.isEnabled = true
}
}
}
}
日志:
2019-07-31 17:02:01.633 3078-3078/com.example.mycalculator E/InputEventSender: Exception dispatching finished signal.
2019-07-31 17:02:01.633 3078-3078/com.example.mycalculator E/MessageQueue-JNI: Exception in MessageQueue callback: handleReceiveCallback
2019-07-31 17:02:01.637 3078-3078/com.example.mycalculator E/MessageQueue-JNI: kotlin.NotImplementedError: An operation is not implemented: not implemented
at com.example.mycalculator.MainActivity$textWatcher$1.beforeTextChanged(MainActivity.kt:101)