1、Activity01

registerForActivityResult()方法的返回值是一个ActivityResultLauncher对象,里边有个launch()方法，直接调用，然后向里传参数intent就可以了

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        var binding = ActivityMainBinding.inflate(layoutInflater)

        setContentView(binding.root)

        val startActivity = registerForActivityResult(ActivityResultContracts.StartActivityForResult()){
            if (it.data!=null&&it.resultCode== Activity.RESULT_OK){
                var params = it.data?.getStringExtra("back_data")?.let {
                        result -> Toast.makeText(this,result,Toast.LENGTH_SHORT).show()
                }
            }else{
                Toast.makeText(this,"获取不到数据",Toast.LENGTH_SHORT).show()
            }
        }

        binding.button01.setOnClickListener {
            val intent = Intent(this,SecondActivity::class.java)
            startActivity.launch(intent)
        }
    }
    
}

2、Activity02

class SecondActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.second_activity)
        val intent = Intent()
        intent.putExtra("back_data","hello This is a message for backData")
        setResult(Activity.RESULT_OK,intent)
        finish()
    }
}