【Android】intent数据传输registerForActivityResult

刚开始学Android，书上是onActivityResult获取Activity返回的数据，但是Android Studio提示

'onActivityResult(Int, Int, Intent?): Unit' is deprecated. Overrides deprecated member in 'androidx.activity.ComponentActivity'. Deprecated in Java

记录一下简单的使用替代品registerForActivityResult的情况。

MainActivity.kt

class MainActivity : AppCompatActivity() {
	// 声明
    private val myOnActivityResult = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {
    		// 在此处处理返回数据
            val data = it.data?.getStringExtra("value")
        	// 使用Toast显示返回的字符串
            Toast.makeText(this, data, Toast.LENGTH_SHORT).show()
        }

    override fun onCreate(savedInstanceState: Bundle?) {
        ...
        binding.bt.setOnClickListener {
            val intent = Intent(this, SecondActivity::class.java)
            intent.putExtra("value","传入的字符串")
            //此处调用打开另一个Activity
            myOnActivityResult.launch(intent)
        }
        ...
    }
...
}

SecondActivity.kt

class SecondActivity : AppCompatActivity() {
	...
    override fun onCreate(savedInstanceState: Bundle?) {
        ...
        //接收传入数据
        val data = intent.getStringExtra("value").toString()
        // 使用Toast显示返回的字符串
        Toast.makeText(this, data, Toast.LENGTH_SHORT).show()
        // 返回数据
        binding.bt.setOnClickListener {
            intent.putExtra("value", "返回的字符串")
            setResult(RESULT_OK, intent)
            finish()
        }
        ...
    }
    ...
}