Kotlin函数仅部分生效：登录成功日志输出但后续日志无输出？

问题描述 #

代码执行到Log.d(TAG, "signInWithCredential:success")时，Logcat能正常输出该日志，但紧随其后的Log.d("tag", "User: $user")及后续所有日志均无输出，相关代码如下：

private fun signInWithPhoneAuthCredential(credential: PhoneAuthCredential) {
    mAuth.signInWithCredential(credential)
        .addOnCompleteListener(this) { task ->
            val user = task.result?.user // Declare and initialize the user variable

            if (task.isSuccessful) {
                // Sign in success, update UI with the signed-in user's information
                Log.d(TAG, "signInWithCredential:success")

                Log.d("tag", "User: $user") // Log the user value here

                if (user != null) {
                    Log.d("tag", "User is not null")
                    val userId: String = user.uid
                    val users = Users(userId, "", "${user.phoneNumber}", "", "", "", "", "", "", "")

                    firestore.collection("Users").document("UserInfo").collection(userId)
                        .add(users)
                        .addOnSuccessListener {
                            Log.d("tag", "Database operation success")
                            startActivity(Intent(applicationContext, SetUserInfoActivity::class.java))
                            progressDialog.dismiss()
                        }
                        .addOnFailureListener { e ->
                            Log.d("tag", "Database operation failed: ${e.message}")
                            progressDialog.dismiss()

                        }
                } else {
                    Log.d("tag", "User is null")
                    Toast.makeText(applicationContext, "Something went wrong", Toast.LENGTH_SHORT).show()
                }

            } else {
                // Sign in failed, display a message and update the UI
                progressDialog.dismiss()
                Log.w(TAG, "signInWithCredential:failure", task.exception)
                if (task.exception is FirebaseAuthInvalidCredentialsException) {
                    // The verification code entered was invalid
                }
                // Update UI
            }
        }
}

可能原因及解决方法 #

• Logcat过滤规则限制：检查Logcat的过滤条件，是否仅设置了显示TAG标签的日志，导致tag标签的日志被过滤。可以清空过滤条件，或直接搜索tag关键词查看对应日志。

• 日志代码抛出未捕获异常：虽然登录成功，但打印User: $user时可能因user对象的toString()方法异常、或变量解析错误导致代码中断。可以用try-catch包裹日志代码排查：

  try {
      Log.d("tag", "User: $user")
  } catch (e: Exception) {
      Log.e("tag", "打印用户信息出错: ${e.message}", e)
  }
  

• 页面跳转提前终止进程：如果startActivity执行后当前Activity被快速销毁，可能后续日志还未完成输出就被终止。可以暂时注释掉startActivity和progressDialog.dismiss()，验证日志是否正常输出。

• Firestore操作阻塞主线程：Firestore的写入操作如果在UI线程执行，可能导致主线程卡顿，日志输出被延迟或中断。可以将Firestore操作移至后台线程执行，例如使用Coroutine：

  if (user != null) {
      Log.d("tag", "User is not null")
      val userId: String = user.uid
      val users = Users(userId, "", "${user.phoneNumber}", "", "", "", "", "", "", "")
  
      CoroutineScope(Dispatchers.IO).launch {
          try {
              firestore.collection("Users").document("UserInfo").collection(userId)
                  .add(users)
              withContext(Dispatchers.Main) {
                  Log.d("tag", "Database operation success")
                  startActivity(Intent(applicationContext, SetUserInfoActivity::class.java))
                  progressDialog.dismiss()
              }
          } catch (e: Exception) {
              withContext(Dispatchers.Main) {
                  Log.d("tag", "Database operation failed: ${e.message}")
                  progressDialog.dismiss()
              }
          }
      }
  }
  

• 变量解析异常：尝试直接打印user的具体属性（如uid、phoneNumber），避免调用整个对象的toString()方法，排查是否是对象序列化问题：

  Log.d("tag", "用户UID: ${user?.uid}, 手机号: ${user?.phoneNumber}")
  

内容的提问来源于stack exchange，提问作者Murad Axundov