android - 使用 Kotlin 的 Android：新活动不显示任何内容，全是空白？

Question

我正在尝试在 android 开发中测试自己。为此，我试图在 firebase 的帮助下制作社交媒体应用程序（使用 firebase 身份验证），但问题是。在我使用正确的每个凭据登录后，它没有显示下一个要打开的活动屏幕。我不知道我犯了什么错误。这是 loginAcitivity 屏幕的代码：

class LoginActivity : AppCompatActivity() {

    private val firebaseAuth = FirebaseAuth.getInstance()
    private val firebaseAuthListener = FirebaseAuth.AuthStateListener {
        val user = firebaseAuth.currentUser?.uid
        user?.let {
            startActivity(HomeActivity.newIntent(this))
            finish()
        }
    }

    @SuppressLint("ClickableViewAccessibility")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_login)

        setTextChangeListener(emailET, emailTIL)
        setTextChangeListener(passwordET, passwordTIL)

        loginProgressLayout.setOnTouchListener { v :View, event :MotionEvent  -> true  }

    }

    private fun setTextChangeListener(et: EditText, til: TextInputLayout) {
        et.addTextChangedListener(object: TextWatcher{
            override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {

            }

            override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {

            }

            override fun afterTextChanged(s: Editable?) {
                til.isErrorEnabled = false
            }

        })
    }

    fun onLogin(v: View){
        var proceed = true
        if(emailET.text.isNullOrEmpty()){
            emailTIL.error = "Email is required"
            emailTIL.isErrorEnabled = true
            proceed = false
        }
        if(passwordET.text.isNullOrEmpty()){
            passwordTIL.error ="Password is required"
            passwordTIL.isErrorEnabled = true
            proceed = false
        }
        if(proceed){
            loginProgressLayout.visibility = View.VISIBLE
            firebaseAuth.signInWithEmailAndPassword(emailET.text.toString(), passwordET.text.toString())
                .addOnCompleteListener { task: Task<AuthResult> ->
                    if (!task.isSuccessful) {
                        loginProgressLayout.visibility = View.GONE
                        Toast.makeText(this@LoginActivity, "Login error: Either the username or password is wrong.", Toast.LENGTH_SHORT).show()
                    }
                }.addOnFailureListener{e: Exception ->
                    e.printStackTrace()
                    loginProgressLayout.visibility = View.GONE
                }
        }
    }

    fun goToSignUp(v: View){
        startActivity(SignUpActivity.newIntent(this))
        finish()
    }

    override fun onStart() {
        super.onStart()
        firebaseAuth.addAuthStateListener { firebaseAuthListener }
    }

    override fun onStop() {
        super.onStop()
        firebaseAuth.removeAuthStateListener { firebaseAuthListener }
    }

    companion object{
        fun newIntent(context: Context) = Intent(context, LoginActivity::class.java)
    }
}

为了测试身份验证是否有效，我在活动中放置了一个按钮以注销。

请帮助我，自从我坚持下去已经一周了。

标签： androidfirebasekotlinandroid-activity

Answer 1

您正在使用 lambda 并且在那里您没有执行任何任务。

override fun onStart() {
        super.onStart()
        firebaseAuth.addAuthStateListener(firebaseAuthListener)
    }

    override fun onStop() {
        super.onStop()
        firebaseAuth.removeAuthStateListener(firebaseAuthListener)
    }