안드로이드 앱 개발 연습 - 2 | Activity

SubActivity 실행 및 데이터 넘기기

MainActivity.kt

class MainActivity : AppCompatActivity() {
    private val binding by lazy { ActivityMainBinding.inflate(layoutInflater) }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        val intent = Intent(this, SubActivity::class.java)
        intent.putExtra("data1", "First Data")
        intent.putExtra("data2", 2022)

        binding.goToSubBtn.setOnClickListener { startActivity(intent) }
    }
}

SubActivity.kt

class SubActivity : AppCompatActivity() {
    private val binding by lazy { ActivitySubBinding.inflate(layoutInflater) }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        binding.Data1.text = intent.getStringExtra("data1")
        binding.Data2.text = "${intent.getIntExtra("data2", 0)}"
    }
}

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MainAcitivity에서 값 돌려받기

SubActivity.kt

class SubActivity : AppCompatActivity() {
    private val binding by lazy { ActivitySubBinding.inflate(layoutInflater) }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        binding.Data1.text = intent.getStringExtra("data1")
        binding.Data2.text = "${intent.getIntExtra("data2", 0)}"
        binding.exitBtn.setOnClickListener {
            val returnIntent = Intent()
            returnIntent.putExtra("returnValue", binding.returnMessage.text.toString())
            setResult(RESULT_OK, returnIntent)
            finish()
        }
    }
}

MainActivity.kt

class MainActivity : AppCompatActivity() {
    private val binding by lazy { ActivityMainBinding.inflate(layoutInflater) }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        val activityResult = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {
            if (it.resultCode == RESULT_OK) {
                val message = it.data?.getStringExtra("returnValue")
                binding.textView2.text = message
            }
        }

        val intent = Intent(this, SubActivity::class.java)
        intent.putExtra("data1", "First Data")
        intent.putExtra("data2", 2022)

        binding.goToSubBtn.setOnClickListener { activityResult.launch(intent) }
    }
}

build.gradle (Module: Activity.app)

dependencies {

    def dependency_version = "1.3.1"
    implementation "androidx.activity:activity-ktx:$dependency_version"
    implementation "androidx.fragment:fragment-ktx:$dependency_version"
    ...
}