Android Kotlin中Fragment编译报错“onCreate overrides nothing”求助

你遇到的编译错误核心原因是方法名大小写错误：你定义的生命周期方法写成了oncreate（小写字母c），但Fragment类中对应的生命周期方法正确名称是onCreate（大写字母C）。Kotlin是严格区分大小写的语言，所以这个方法并没有正确覆盖父类的方法，从而触发“onCreate overrides nothing”错误。

修改后的正确代码如下：

package com.bignerdranch.android.criminalintent

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.core.widget.doOnTextChanged
import androidx.fragment.app.Fragment
import com.bignerdranch.android.criminalintent.databinding.FragmentCrimeDetailBinding
import java.util.UUID

class CrimeDetailFragment : Fragment() {

    private lateinit var binding: FragmentCrimeDetailBinding

    private lateinit var crime: Crime

    // 修正方法名：oncreate -> onCreate
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        crime = Crime(
            id = UUID.randomUUID(),
            title = "",
            date = java.util.Date(),
            isSolved = false
        )
    }

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ) : View? {
        binding = FragmentCrimeDetailBinding.inflate(inflater, container, false)
        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        binding.apply {
            crimeTitle.doOnTextChanged { text, _, _, _ ->
                crime = crime.copy(title = text.toString())
            }

            crimeDate.apply {
                text = crime.date.toString()
                isEnabled = false
            }

            crimeSolved.setOnCheckedChangeListener { _, isChecked ->
                crime = crime.copy(isSolved = isChecked)
            }
        }
    }
}

内容的提问来源于stack exchange，提问作者Ted