[Kotlin] Lifecycle, LifecycleOwner, LifecycleObserver

Lifecycle

LifecycleOwner

LifecycleObserver

---

MainActivity.kt

package com.example.lifecycleexample

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.widget.Button
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.LifecycleEventObserver

class MainActivity : AppCompatActivity() {

    private val btShow: Button by lazy {
        findViewById(R.id.bt_show)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val bottomLifecycleObserver = LifecycleEventObserver { source, event ->
            when (source.lifecycle.currentState) {
                Lifecycle.State.CREATED -> Log.e("", "MainActivity :: Lifecycle.State.CREATED")
                Lifecycle.State.STARTED -> Log.e("", "MainActivity :: Lifecycle.State.STARTED")
                Lifecycle.State.DESTROYED -> Log.e("", "MainActivity :: Lifecycle.State.DESTROYED")
            }

            when (event) {
                Lifecycle.Event.ON_CREATE -> Log.e("", "MainActivity :: Lifecycle.Event.ON_CREATE")
                Lifecycle.Event.ON_START -> Log.e("", "MainActivity :: Lifecycle.Event.ON_START")
                Lifecycle.Event.ON_RESUME -> Log.e("", "MainActivity :: Lifecycle.Event.ON_RESUME")
                Lifecycle.Event.ON_PAUSE -> Log.e("", "MainActivity :: Lifecycle.Event.ON_PAUSE")
                Lifecycle.Event.ON_STOP -> Log.e("", "MainActivity :: Lifecycle.Event.ON_STOP")
                Lifecycle.Event.ON_DESTROY -> Log.e("", "MainActivity :: Lifecycle.Event.ON_DESTROY")
            }
        }

        btShow.setOnClickListener {
            TestDialog().apply {
                lifecycleObserver = bottomLifecycleObserver
            }.show(supportFragmentManager, "TestDialog")

        }
    }

}

다이얼로그의 생명주기에 반응하여 로그를 출력. (LifecycleObserver)

 

 

 

 

 

TestDialog.kt

package com.example.lifecycleexample

import android.os.Bundle
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.lifecycle.LifecycleObserver
import com.google.android.material.bottomsheet.BottomSheetDialogFragment

class TestDialog : BottomSheetDialogFragment() {

    lateinit var lifecycleObserver: LifecycleObserver

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        Log.e("", "TestDialog :: onCreate()")
    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?
    ): View? {
        viewLifecycleOwner.lifecycle.addObserver(lifecycleObserver)
        Log.e("", "TestDialog :: onCreateView()")
        return inflater.inflate(R.layout.dialog_test, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        Log.e("", "TestDialog :: onViewCreated()")
    }

    override fun onActivityCreated(savedInstanceState: Bundle?) {
        super.onActivityCreated(savedInstanceState)
        Log.e("", "TestDialog :: onActivityCreated()")
    }

    override fun onStart() {
        super.onStart()
        Log.e("", "TestDialog :: onStart()")
    }

    override fun onResume() {
        super.onResume()
        Log.e("", "TestDialog :: onResume()")
    }

    override fun onPause() {
        super.onPause()
        Log.e("", "TestDialog :: onPause()")
    }

    override fun onStop() {
        super.onStop()
        Log.e("", "TestDialog :: onStop()")
    }

    override fun onDestroy() {
        super.onDestroy()
        Log.e("", "TestDialog :: onDestroy()")
    }

}

MainActivity 에서 생선한 lifecycleObserver 를 다이얼로그의 생명주기에 추가한다.

viewLifecycleOwner.lifecycle.addObserver(lifecycleObserver)

 

 

실행 결과

 

다이얼로그 띄웠을 때

 

다이얼로그 없어졌을 때