LifeCycleObserveableLogger

LifeCycleObserveableLogger.kt

import android.util.Log
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.LifecycleObserver
import androidx.lifecycle.OnLifecycleEvent

object IndentProvider {
    private var depth = 0
    private const val SPACE = "  "

    fun getAndIncrement(): String {
        require(depth >= 0)
        val indentSpace = (0 until depth).joinToString(separator = "") { SPACE }
        depth++
        return indentSpace
    }

    fun incrementAndGet(): String {
        require(depth >= 0)
        depth++
        return (0 until depth).joinToString(separator = "") { SPACE }
    }

    fun getAndDecrement(): String {
        require(depth >= 0)
        val indentSpace = (0 until depth).joinToString(separator = "") { SPACE }
        depth--
        check(depth >= 0)
        return indentSpace
    }

    fun decrementAndGet(): String {
        require(depth >= 0)
        depth--
        check(depth >= 0)
        return (0 until depth).joinToString(separator = "") { SPACE }
    }

    fun current(): String {
        require(depth >= 0)
        return (0 until depth).joinToString(separator = "") { SPACE }
    }
}

class IndentLogger(tag: String) {
    private val prefix: String = run {
        val tagSize = tag.length
        (0 until 13).map { if (it < tagSize) tag[it] else " " }.joinToString(separator = "")
    }
    fun logAndIncrement(tag: String, msg: String) {
        Log.d(tag, "${IndentProvider.getAndIncrement()}[$prefix]-$msg")
    }

    fun decrementAndLog(tag: String, msg: String) {
        Log.d(tag, "${IndentProvider.decrementAndGet()}[$prefix]-$msg")
    }

    fun log(tag: String, msg: String) {
        Log.d(tag, "${IndentProvider.current()}[$prefix]-$msg")
    }
}

class LifeCycleObservableLogger(val logger: IndentLogger) : LifecycleObserver {
    companion object {
        const val TAG = "LifeCycleLog"
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_CREATE)
    fun onCreated() = logger.logAndIncrement(TAG, "ON_CREATE")

    @OnLifecycleEvent(Lifecycle.Event.ON_START)
    fun onStarted() = logger.logAndIncrement(TAG, "ON_START")

    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
    fun onResumed() = logger.logAndIncrement(TAG, "ON_RESUME")

    @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
    fun onPaused() = logger.decrementAndLog(TAG, "ON_PAUSE")

    @OnLifecycleEvent(Lifecycle.Event.ON_STOP)
    fun onStopped() = logger.decrementAndLog(TAG, "ON_STOP")

    @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
    fun onDestroyed() = logger.decrementAndLog(TAG, "ON_DESTROY")

    fun onSaveInstanceState() = logger.log(TAG, "ON_SAVE_INSTANCE_STATE")
    fun onRestoreSavedInstanceState() = logger.log(TAG, "ON_RESTORE_SAVED_INSTANCE_STATE")
    fun onConfigurationChanged() = logger.log(TAG, "ON_CONFIGURATION_CHANGED")
    fun onCreateView() = logger.log(TAG, "ON_CREATE_VIEW")
    fun onViewCreated() = logger.log(TAG, "ON_VIEW_CREATED")
    fun onDestroyView() = logger.log(TAG, "ON_DESTROY_VIEW")
    fun onViewStateRestored() = logger.log(TAG, "ON_VIEW_STATE_RESTORED")
}

Activity

class MainActivity : AppCompatActivity() {

    private lateinit var appBarConfiguration: AppBarConfiguration
    private lateinit var binding: ActivityMainBinding

    private val logger = LifeCycleObservableLogger(IndentLogger("MainActivity"))
    init {
        lifecycle.addObserver(logger)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        setSupportActionBar(binding.toolbar)

        val navController = findNavController(R.id.nav_host_fragment_content_main)
        appBarConfiguration = AppBarConfiguration(navController.graph)
        setupActionBarWithNavController(navController, appBarConfiguration)

        binding.fab.setOnClickListener { view ->
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                .setAction("Action", null).show()
        }
    }

    override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)
        logger.onSaveInstanceState()
    }

    override fun onRestoreInstanceState(savedInstanceState: Bundle) {
        super.onRestoreInstanceState(savedInstanceState)
        logger.onRestoreSavedInstanceState()
    }

    override fun onConfigurationChanged(newConfig: Configuration) {
        super.onConfigurationChanged(newConfig)
        logger.onConfigurationChanged()
    }
}

Fragment

class FirstFragment : Fragment() {

    private val logger = LifeCycleObservableLogger(IndentLogger("FirstFragment"))
    init {
        lifecycle.addObserver(logger)
    }

    private var _binding: FragmentFirstBinding? = null

    // This property is only valid between onCreateView and
    // onDestroyView.
    private val binding get() = _binding!!

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

    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        logger.onViewCreated()
        binding.buttonFirst.setOnClickListener {
            findNavController().navigate(R.id.action_FirstFragment_to_SecondFragment)
        }
    }

    override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)
        logger.onSaveInstanceState()
    }

    override fun onViewStateRestored(savedInstanceState: Bundle?) {
        super.onViewStateRestored(savedInstanceState)
        logger.onViewStateRestored()
    }

    override fun onConfigurationChanged(newConfig: Configuration) {
        super.onConfigurationChanged(newConfig)
        logger.onConfigurationChanged()
    }

    override fun onDestroyView() {
        super.onDestroyView()
        logger.onDestroyView()
        _binding = null
    }
}

License

Copyright [yyyy] [name of copyright owner]

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

• No configChanges options.

launch

D/LifeCycleLog: [FirstFragment]-ON_CREATE
D/LifeCycleLog:   [MainActivity ]-ON_CREATE
D/LifeCycleLog:     [FirstFragment]-ON_CREATE_VIEW
D/LifeCycleLog:     [FirstFragment]-ON_VIEW_CREATED
D/LifeCycleLog:     [FirstFragment]-ON_VIEW_STATE_RESTORED
D/LifeCycleLog:     [FirstFragment]-ON_START
D/LifeCycleLog:       [MainActivity ]-ON_START
D/LifeCycleLog:         [FirstFragment]-ON_RESUME
D/LifeCycleLog:           [MainActivity ]-ON_RESUME

launch other app and back.

 D/LifeCycleLog:           [MainActivity ]-ON_PAUSE
 D/LifeCycleLog:         [FirstFragment]-ON_PAUSE
 D/LifeCycleLog:       [MainActivity ]-ON_STOP
 D/LifeCycleLog:     [FirstFragment]-ON_STOP
 D/LifeCycleLog:     [FirstFragment]-ON_SAVE_INSTANCE_STATE
 D/LifeCycleLog:     [MainActivity ]-ON_SAVE_INSTANCE_STATE
 D/LifeCycleLog:     [FirstFragment]-ON_START
 D/LifeCycleLog:       [MainActivity ]-ON_START
 D/LifeCycleLog:         [FirstFragment]-ON_RESUME
 D/LifeCycleLog:           [MainActivity ]-ON_RESUME

launch other app and back. (don't keep activity)

D/LifeCycleLog:           [MainActivity ]-ON_PAUSE
D/LifeCycleLog:         [FirstFragment]-ON_PAUSE
D/LifeCycleLog:       [MainActivity ]-ON_STOP
D/LifeCycleLog:     [FirstFragment]-ON_STOP
D/LifeCycleLog:     [FirstFragment]-ON_SAVE_INSTANCE_STATE
D/LifeCycleLog:     [MainActivity ]-ON_SAVE_INSTANCE_STATE
D/LifeCycleLog:   [MainActivity ]-ON_DESTROY
D/LifeCycleLog:   [FirstFragment]-ON_DESTROY_VIEW
D/LifeCycleLog: [FirstFragment]-ON_DESTROY
D/LifeCycleLog: [FirstFragment]-ON_CREATE
D/LifeCycleLog:   [MainActivity ]-ON_CREATE
D/LifeCycleLog:     [FirstFragment]-ON_CREATE_VIEW
D/LifeCycleLog:     [FirstFragment]-ON_VIEW_CREATED
D/LifeCycleLog:     [FirstFragment]-ON_VIEW_STATE_RESTORED
D/LifeCycleLog:     [FirstFragment]-ON_START
D/LifeCycleLog:       [MainActivity ]-ON_START
D/LifeCycleLog:         [MainActivity ]-ON_RESTORE_SAVED_INSTANCE_STATE
D/LifeCycleLog:         [FirstFragment]-ON_RESUME
D/LifeCycleLog:           [MainActivity ]-ON_RESUME

rotate

same recreation log with don't keep activity.

D/LifeCycleLog:           [MainActivity ]-ON_PAUSE
D/LifeCycleLog:         [FirstFragment]-ON_PAUSE
D/LifeCycleLog:       [MainActivity ]-ON_STOP
D/LifeCycleLog:     [FirstFragment]-ON_STOP
D/LifeCycleLog:     [FirstFragment]-ON_SAVE_INSTANCE_STATE
D/LifeCycleLog:     [MainActivity ]-ON_SAVE_INSTANCE_STATE
D/LifeCycleLog:   [MainActivity ]-ON_DESTROY
D/LifeCycleLog:   [FirstFragment]-ON_DESTROY_VIEW
D/LifeCycleLog: [FirstFragment]-ON_DESTROY
D/LifeCycleLog: [FirstFragment]-ON_CREATE
D/LifeCycleLog:   [MainActivity ]-ON_CREATE
D/LifeCycleLog:     [FirstFragment]-ON_CREATE_VIEW
D/LifeCycleLog:     [FirstFragment]-ON_VIEW_CREATED
D/LifeCycleLog:     [FirstFragment]-ON_VIEW_STATE_RESTORED
D/LifeCycleLog:     [FirstFragment]-ON_START
D/LifeCycleLog:       [MainActivity ]-ON_START
D/LifeCycleLog:         [MainActivity ]-ON_RESTORE_SAVED_INSTANCE_STATE
D/LifeCycleLog:         [FirstFragment]-ON_RESUME
D/LifeCycleLog:           [MainActivity ]-ON_RESUME