无法从编辑文本获取数据，Android Kotlin

Question

当我尝试从edittext获取数据时得到空数据，这是我的代码

class LoginActivity : AppCompatActivity() {
lateinit var etUsername : EditText
lateinit var etPassword : EditText
var username = ""
var password = ""
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_login)
    etPassword = findViewById(R.id.tanggalLahir) as EditText
    etUsername = findViewById(R.id.nomerInduk) as EditText
    username = etUsername.text.toString()
    password = etPassword.text.toString()

    buttonLogin.setOnClickListener() {
        if (username.isEmpty()){
            Log.d("User", "Username = $username")
            nomerInduk.error = "Nomor Induk Kosong!"
            return@setOnClickListener
        }

        if (password.isEmpty()){
            Log.d("User", "Password = $password")
            tanggalLahir.error = "Tanggal Lahir Kosong!"
            return@setOnClickListener
        }

        login(username,password)
    }


}

当我签入log image check log的时候

我已经将edittext更改为textinputedittext，但仍然相同

Answer 1

class LoginActivity : AppCompatActivity() {
lateinit var etUsername : EditText
lateinit var etPassword : EditText
var username = ""
var password = ""
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_login)
    etPassword = findViewById(R.id.tanggalLahir) as EditText
    etUsername = findViewById(R.id.nomerInduk) as EditText


    buttonLogin.setOnClickListener() {
username = etUsername.text.toString()
    password = etPassword.text.toString()
        if (username.isEmpty()){
            Log.d("User", "Username = $username")
            nomerInduk.error = "Nomor Induk Kosong!"
            return@setOnClickListener
        }

        if (password.isEmpty()){
            Log.d("User", "Password = $password")
            tanggalLahir.error = "Tanggal Lahir Kosong!"
            return@setOnClickListener
        }

        login(username,password)
    }


}

Answer 2

class LoginActivity : AppCompatActivity() {
lateinit var etUsername : EditText
lateinit var etPassword : EditText
var username = ""
var password = ""
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_login)
    etPassword = findViewById(R.id.tanggalLahir) as EditText
    etUsername = findViewById(R.id.nomerInduk) as EditText


    buttonLogin.setOnClickListener() {
    // once button click you have to get the current text value from the edit text what you have entered. 
    username = etUsername.text.toString()
    password = etPassword.text.toString()
        if (username.isEmpty()){
            Log.d("User", "Username = $username")
            nomerInduk.error = "Nomor Induk Kosong!"
            return@setOnClickListener
        }

        if (password.isEmpty()){
            Log.d("User", "Password = $password")
            tanggalLahir.error = "Tanggal Lahir Kosong!"
            return@setOnClickListener
        }

        login(username,password)
    }


}

你必须学习android的基本生命周期。在这里，您第一次获得了编辑文本值，并将其分配给全局变量username和password。但是在您输入了一些内容并单击enter之后，您必须在单击submit按钮时获得新添加的文本值。这就是为什么那些赋值代码会进入到按钮点击的内部。