（Android アプリ開発の）その書き方古いかも。/ Devfest Tokyo 2021

Transcript

1. DevFest Tokyo 2021
   Yuki Anzai（@yanzm） 
   GDE for Android 
   その書き⽅古いかも。
   

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2. 最近のリリース
   • 2018  android 9 Pie    API Level 28
   • 2019  android 10（Q）  API Level 29
   • 2020  android 11（R）  API Level 30
   • 2021  android 12（S）  API Level 31
   

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3. Android Framework
   

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4. Activity
   

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5. [deprecated] onStateNotSaved()
   Activity
   • API Level 28（Android P）から onSaveInstanceState() は onStop() の後に呼
   ばれるようになった
   • ↑に伴い、このメソッドは不正確になったので廃⽌
   

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6. android.preference
   

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7. [deprecated] android.preference
   • 新しい⽅法
   • AndroidX の Preference Library (androidx.preference) を使う
   

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8. [deprecated] android.preference
   • 新しい⽅法
   • AndroidX の Preference Library (androidx.preference) を使う
   SharedPreferences         → Android フレームワーク
   （key-value pair を保存する仕組み）
   設定画⾯を簡単に作る機能     →  AndroidX
   （SharedPreferences を        （ライブラリ）
   設定値保存に使⽤）
   

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9. AndroidX
   

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10. ComponentActivity
    FragmentActivity
    

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11. 継承関係
    androidx
    • ComponentActivity
    • FragmentActivity
    • AppCompatActivity
    

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12. [deprecated] startActivityForResult(), onActivityResult()
    ComponentActivity
    • 新しい⽅法 : ActivityResultContract を使う
    

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13. 以前の⽅法
    class OldMainActivity : ComponentActivity()
    {
    
    …
    private fun doSomething()
    {
    
    startActivityForResult(Intent(this, DoSomethingActivity::class.java), REQUEST_CODE
    )
    
    }
    
    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?)
    {
    
    super.onActivityResult(requestCode, resultCode, data
    )
    
    if (requestCode == REQUEST_CODE && resultCode == RESULT_OK)
    {
    
    val id = data?.getStringExtra("id"
    )
    
    if (id != null)
    {
    
    // ..
    .
    
    }
    
    }
    
    }
    
    }
    

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14. 新しい⽅法
    class MainActivity : ComponentActivity()
    {
    
    …
    private val doSomethingLauncher
    =
    
    registerForActivityResult(ActivityResultContracts.StartActivityForResult())
    {
    
    if (it.resultCode == RESULT_OK)
    {
    
    val id = it.data?.getStringExtra("id"
    )
    
    if (id != null)
    {
    
    // ..
    .
    
    }
    
    }
    
    }
    
    private fun doSomething()
    {
    
    doSomethingLauncher.launch(Intent(this, DoSomethingActivity::class.java)
    )
    
    }
    
    }
    

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15. [deprecated] onRequestPermissionsResult()
    ComponentActivity
    • 新しい⽅法 : ActivityResultContract を使う
    

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16. 以前の⽅法
    class OldMainActivity : ComponentActivity()
    {
    
    private fun requestCameraPermission()
    {
    
    requestPermissions(arrayOf(Manifest.permission.CAMERA), REQUEST_CODE
    )
    
    }
    
    override fun onRequestPermissionsResult
    (
    
    requestCode: Int
    ,
    
    permissions: Array
    ,
    
    grantResults: IntArra
    y
    
    )
    {
    
    super.onRequestPermissionsResult(requestCode, permissions, grantResults
    )
    
    if (requestCode == REQUEST_CODE)
    {
    
    if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
    {
    
    doSomethingWithCamera(
    )
    
    } else
    {
    
    // show messag
    e
    
    }
    
    }
    
    }
    
    …
    }
    

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17. 新しい⽅法
    class MainActivity : ComponentActivity()
    {
    
    private val requestCameraPermissionLauncher
    =
    
    registerForActivityResult(ActivityResultContracts.RequestPermission()) { granted -
    >
    
    if (granted)
    {
    
    doSomethingWithCamera(
    )
    
    } else
    {
    
    // show messag
    e
    
    }
    
    }
    
    private fun requestCameraPermission()
    {
    
    requestCameraPermissionLauncher.launch(Manifest.permission.CAMERA
    )
    
    }
    
    …
    }
    

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18. [deprecated] startIntentSenderForResult()
    ComponentActivity
    • 新しい⽅法 : ActivityResultContract を使う
    FragmentActivity
    [deprecated] startIntentSenderFromFragment()
    

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19. 新しい⽅法
    class MainActivity : ComponentActivity()
    {
    
    …
    private val doSomethingIntentSenderLauncher
    =
    
    registerForActivityResult(ActivityResultContracts.StartIntentSenderForResult())
    {
    
    if (it.resultCode == RESULT_OK)
    {
    
    val id = it.data?.getStringExtra("id"
    )
    
    if (id != null)
    {
    
    // ..
    .
    
    }
    
    }
    
    }
    
    private fun doSomething()
    {
    
    doSomethingIntentSenderLauncher.launch
    (
    
    IntentSenderRequest.Builder
    (
    
    PendingIntent.getActivity(…
    )
    
    ).build(
    )
    
    )
    
    }
    
    }
    

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20. [deprecated] onAttachFragment()
    FragmentActivity
    • 新しい⽅法 : FragmentManager の addFragmentOnAttachListener() を使う
    

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21. 以前の⽅法
    class MainActivity : FragmentActivity()
    {
    
    override fun onAttachFragment(fragment: Fragment)
    {
    
    super.onAttachFragment(fragment
    )
    
    if (fragment is MainFragment)
    {
    
    // do somethin
    g
    
    }
    
    }
    
    …
    
    }
    

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22. 新しい⽅法
    class MainActivity : FragmentActivity()
    {
    
    private val listener = FragmentOnAttachListener { fragmentManager, fragment -
    >
    
    if (fragment is MainFragment)
    {
    
    // do somethin
    g
    
    }
    
    }
    
    override fun onCreate(savedInstanceState: Bundle?)
    {
    
    super.onCreate(savedInstanceState
    )
    
    setContentView(R.layout.activity_main
    )
    
    supportFragmentManager.addFragmentOnAttachListener(listener
    )
    
    }
    
    …
    }
    

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23. OnBackPressedDispatcher
    ComponentActivity
    • Back ボタンが押されたときの処理を登録できるようになった
    

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24. 以前の⽅法
    class MainActivity : FragmentActivity()
    {
    
    …
    override fun onBackPressed()
    {
    
    val f = supportFragmentManager.findFragmentById(android.R.id.content
    )
    
    if (f is EditFragment)
    {
    
    f.onBackPressed(
    )
    
    } else
    {
    
    super.onBackPressed(
    )
    
    }
    
    }
    
    }
    
    class EditFragment : Fragment()
    {
    
    …
    fun onBackPressed()
    {
    
    // show discard confirm dialo
    g
    
    }
    
    }
    
    

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25. 新しい⽅法
    class EditFragment : Fragment()
    {
    
    override fun onViewCreated(view: View, savedInstanceState: Bundle?)
    {
    
    super.onViewCreated(view, savedInstanceState
    )
    
    // activity-kt
    x
    
    val callback = requireActivity().onBackPressedDispatcher.addCallback
    (
    
    owner = viewLifecycleOwner
    ,
    
    enabled = tru
    e
    
    )
    {
    
    // show discard confirm dialo
    g
    
    }
    
    // callback ΛҰ࣌తʹແޮʹ͍ͨ͠ͱ͖͸
    callback.isEnabled = fals
    e
    
    }
    
    }
    

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26. Fragment
    

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27. FragmentContainerView
    • 以前の⽅法
    • レイアウト XML で タグを使う
    • FrameLayout を Fragment の container として使う
    • 新しい⽅法
    • レイアウト XML で タグを
    使う
    • FragmentContainerView を Fragment の container として使う
    

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28. 以前の⽅法
    t
    
    android:id="@+id/main_fragment
    "
    
    android:name="com.sample.myapplication.MainFragment
    "
    
    android:layout_width="match_parent
    "
    
    android:layout_height="match_parent" /
    >
    
    t
    
    android:id="@+id/fragment_container
    "
    
    android:layout_width="match_parent
    "
    
    android:layout_height="match_parent" />
    supportFragmentManager.beginTransaction(
    )
    
    .replace(R.id.fragment_container, MainFragment()
    )
    
    .commit(
    )
    
    

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29. 新しい⽅法
    w
    
    android:id="@+id/main_fragment
    "
    
    android:name="com.sample.myapplication.MainFragment
    "
    
    android:layout_width="match_parent
    "
    
    android:layout_height="match_parent" /
    >
    
    w
    
    android:id="@+id/fragment_container
    "
    
    android:layout_width="match_parent
    "
    
    android:layout_height="match_parent" />
    supportFragmentManager.beginTransaction(
    )
    
    .replace(R.id.fragment_container, MainFragment()
    )
    
    .commit(
    )
    
    

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30. 新しい⽅法
    w
    
    android:id="@+id/main_fragment
    "
    
    android:name="com.sample.myapplication.MainFragment
    "
    
    android:layout_width="match_parent
    "
    
    android:layout_height="match_parent" /
    >
    
    w
    
    android:id="@+id/fragment_container
    "
    
    android:layout_width="match_parent
    "
    
    android:layout_height="match_parent" />
    supportFragmentManager.beginTransaction(
    )
    
    .replace(R.id.fragment_container, MainFragment()
    )
    
    .commit(
    )
    
    • getFragment() で⼀番最後に追加された Fragment を取得できる
    val fragmentContainerView = findViewById(R.id.fragment_container
    )
    
    val f = fragmentContainerView.getFragment()
    

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31. Fragment のコンストラクタでレイアウトXMLを指定
    • レイアウトXMLを指定できるコンストラクタが⽤意された
    • 指定したレイアウトXMLの View が onCreateView() で⽣成される
    

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32. 以前の⽅法
    新しい⽅法
    class MainFragment : Fragment(R.layout.fragment_main) {
    …
    
    }
    class MainFragment : Fragment
    {
    
    override fun onCreateView
    (
    
    inflater: LayoutInflater
    ,
    
    container: ViewGroup?
    ,
    
    savedInstanceState: Bundle
    ?
    
    ): View = inflater.inflate(R.layout.fragment_main, container, false
    )
    
    …
    
    }
    

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33. FragmentFactory
    • 以前の⽅法
    • Fragment のインスタンスはライブラリによって⽣成させるので、引数なし
    のコンストラクタでなくてはならない
    • 新しい⽅法
    • FragmentFactory を使えば、引数ありのコンストラクタが使える
    

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34. class MainFragment(private val repository: ItemRepository) : Fragment()
    {
    
    …
    
    }
    
    class MainFragmentFactory(private val repository: ItemRepository) : FragmentFactory()
    {
    
    override fun instantiate(classLoader: ClassLoader, className: String): Fragment
    {
    
    return when (loadFragmentClass(classLoader, className))
    {
    
    MainFragment::class.java -> MainFragment(repository
    )
    
    else -> super.instantiate(classLoader, className
    )
    
    }
    
    }
    
    }
    
    class MainActivity : FragmentActivity()
    {
    
    override fun onCreate(savedInstanceState: Bundle?)
    {
    
    val repository: ItemRepository =
    …
    
    supportFragmentManager.fragmentFactory = MainFragmentFactory(repository
    )
    
    super.onCreate(savedInstanceState
    )
    
    …
    
    }
    
    …
    
    }
    ৽͍͠ํ๏
    

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35. [deprecated] getFragmentManager(), requireFragmentManager()
    (androidx) Fragment
    • 新しい⽅法 : getParentFragmentManager() を使う
    

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36. [deprecated] onAttachFragment()
    (androidx) Fragment
    • 新しい⽅法 : getChildFragmentManager() で取得した FragmentManager の
    addFragmentOnAttachListener() を 使う
    

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37. 新しい⽅法
    class MainFragment : Fragment()
    {
    
    private val listener = FragmentOnAttachListener { fragmentManager, fragment -
    >
    
    if (fragment is SettingFragment)
    {
    
    // do somethin
    g
    
    }
    
    }
    
    override fun onCreate(savedInstanceState: Bundle?)
    {
    
    super.onCreate(savedInstanceState
    )
    
    childFragmentManager.addFragmentOnAttachListener(listener
    )
    
    }
    
    …
    
    }
    

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38. [deprecated] onActivityCreated()
    (androidx) Fragment
    • 新しい⽅法 : onViewCreated() を使う
    • Activity の onCreate が呼ばれたときのコールバックが必要な場合は onAttach
    で LifecycleObserver を登録する
    

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39. class MainFragment : Fragment()
    {
    
    override fun onAttach(context: Context)
    {
    
    super.onAttach(context
    )
    
    lifecycle.addObserver(object : DefaultLifecycleObserver
    {
    
    override fun onCreate(owner: LifecycleOwner)
    {
    
    // Activity ͷ onCreate() ͕ݺ͹Εͨͱ͖ʹ΍Γ͍ͨॲཧ
    }
    
    override fun onDestroy(owner: LifecycleOwner)
    {
    
    owner.lifecycle.removeObserver(this
    )
    
    }
    
    }
    )
    
    }
    
    …
    
    }
    • Activity の onCreate が呼ばれたときのコールバックが必要な場合はonAttach で
    LifecycleObserver を登録する
    

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40. [deprecated] getRetainInstance(), setRetainInstance()
    (androidx) Fragment
    • 新しい⽅法 : non-retained Fragment を使い、ViewModel で状態を保持する
    ようにする
    

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41. 以前の⽅法
    class OldFragment : Fragment()
    {
    
    private val data = MutableLiveData>(
    )
    
    override fun onCreate(savedInstanceState: Bundle?)
    {
    
    retainInstance = tru
    e
    
    super.onCreate(savedInstanceState
    )
    
    lifecycleScope.launch
    {
    
    data.value = …
    }
    
    }
    
    override fun onViewCreated(view: View, savedInstanceState: Bundle?)
    {
    
    super.onViewCreated(view, savedInstanceState
    )
    
    data.observe(viewLifecycleOwner)
    {
    
    // show dat
    a
    
    }
    
    }
    
    }
    

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42. 新しい⽅法
    class NewRetainFragment : Fragment()
    {
    
    private val viewModel: MainViewModel by viewModels(
    )
    
    override fun onViewCreated(view: View, savedInstanceState: Bundle?)
    {
    
    super.onViewCreated(view, savedInstanceState
    )
    
    viewModel.data.observe(viewLifecycleOwner)
    {
    
    // show dat
    a
    
    }
    
    }
    
    }
    
    class MainViewModel : ViewModel()
    {
    
    private val _data = MutableLiveData>(
    )
    
    val data: LiveData
    >
    
    get() = _dat
    a
    
    init
    {
    
    viewModelScope.launch
    {
    
    _data.value = …
    }
    
    }
    
    }
    

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43. [deprecated] startActivityForResult(), onActivityResult()
    • 新しい⽅法 : ActivityResultContract を使う
    [deprecated] startIntentSenderForResult()
    (androidx) Fragment
    [deprecated] onRequestPermissionsResult()
    [deprecated] requestPermissions()
    

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44. 新しい⽅法
    class MainFragment : Fragment()
    {
    
    private val doSomethingLauncher
    =
    
    registerForActivityResult(ActivityResultContracts.StartActivityForResult())
    {
    
    if (it.resultCode == Activity.RESULT_OK)
    {
    
    val id = it.data?.getStringExtra("id"
    )
    
    if (id != null)
    {
    
    // ..
    .
    
    }
    
    }
    
    }
    
    private fun doSomething()
    {
    
    doSomethingLauncher.launch(Intent(requireContext(), DoSomethingActivity::class.java)
    )
    
    }
    
    …
    }
    

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45. [deprecated] getTargetFragment() , setTargetFragment()
    (androidx) Fragment
    • 親⼦関係の Fragment 間でデータを受け渡す場合、以前は targetFragment を
    利⽤していたが deprecated になった
    • 新しい⽅法 : Fragment Result API をつかう
    

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46. 以前の⽅法
    class ParentFragment : Fragment()
    {
    
    private fun showMyDialogFragment()
    {
    
    val f = MyDialogFragment(
    )
    
    f.setTargetFragment(this, 10
    )
    
    f.show(childFragmentManager, "MyDialogFragment"
    )
    
    }
    
    fun onNewValue(value: Int)
    {
    
    // show valu
    e
    
    }
    
    }
    
    class MyDialogFragment : DialogFragment()
    {
    
    …
    
    override fun onViewCreated(view: View, savedInstanceState: Bundle?)
    {
    
    super.onViewCreated(view, savedInstanceState
    )
    
    button.setOnClickListener
    {
    
    (targetFragment as? ParentFragment)?.onNewValue(Random.nextInt()
    )
    
    }
    
    }
    
    }
    

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47. 新しい⽅法
    https://developer.android.com/guide/fragments/communicate#fragment-result
    

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48. 新しい⽅法
    class ParentFragment : Fragment()
    {
    
    private fun showMyDialogFragment()
    {
    
    childFragmentManager.setFragmentResultListener("ParentFragment", viewLifecycleOwner) { requestKey, bundle -
    >
    
    onNewValue(bundle.getInt("value")
    )
    
    }
    
    val f = MyDialogFragment(
    )
    
    f.show(childFragmentManager, "MyDialogFragment"
    )
    
    }
    
    private fun onNewValue(value: Int)
    {
    
    // show valu
    e
    
    }
    
    }
    
    class MyDialogFragment : DialogFragment()
    {
    
    …
    
    override fun onViewCreated(view: View, savedInstanceState: Bundle?)
    {
    
    super.onViewCreated(view, savedInstanceState
    )
    
    button.setOnClickListener
    {
    
    setFragmentResult("MyDialogFragment", bundleOf("value" to Random.nextInt())
    )
    
    }
    
    }
    
    }
    同じ FragmentManager 内の
    Fragment 間、
    親⼦関係の Fragment 間
    で使える
    

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49. [deprecated] FragmentPagerAdapter, FragmentStatePagerAdapter
    • ViewPager2 が stable になったことで、ViewPager 向けの Fragment Adapter
    は deprecated になった
    • 新しい⽅法 : ViewPager2 をつかう
    

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50. 以前の⽅法
    class OldViewPagerActivity : FragmentActivity()
    {
    
    override fun onCreate(savedInstanceState: Bundle?)
    {
    
    super.onCreate(savedInstanceState
    )
    
    val viewPager = ViewPager(this).apply
    {
    
    id = R.id.view_page
    r
    
    }
    
    setContentView(viewPager
    )
    
    viewPager.adapter = MyPagerAdapter(supportFragmentManager
    )
    
    }
    
    }
    
    class MyPagerAdapter(fragmentManager: FragmentManager) : FragmentPagerAdapter(fragmentManager)
    {
    
    override fun getCount(): Int
    {
    
    return 1
    0
    
    }
    
    override fun getItem(position: Int): Fragment
    {
    
    return
    …
    
    }
    
    }
    

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51. 新しい⽅法
    class NewViewPagerActivity : FragmentActivity()
    {
    
    override fun onCreate(savedInstanceState: Bundle?)
    {
    
    super.onCreate(savedInstanceState
    )
    
    val viewPager = ViewPager2(this).apply
    {
    
    id = R.id.view_page
    r
    
    }
    
    setContentView(viewPager
    )
    
    viewPager.adapter = MyPagerAdapter(this
    )
    
    }
    
    }
    
    class MyPagerAdapter(activity: FragmentActivity) : FragmentStateAdapter(activity)
    {
    
    override fun getItemCount(): Int
    {
    
    return 1
    0
    
    }
    
    override fun createFragment(position: Int): Fragment
    {
    
    return
    …
    
    }
    
    }
    

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52. deprecated になった Fragment 機能の利⽤を検出する
    • StrictMode for Fragment （1.4.0 〜）
    class ExampleActivity : AppCompatActivity()
    {
    
    init
    {
    
    supportFragmentManager.strictModePolicy
    =
    
    FragmentStrictMode.Policy.Builder(
    )
    
    .penaltyDeath(
    )
    
    .detectRetainInstanceUsage(
    )
    
    .allowViolation(ThirdPartyFragment::class.java, RetainInstanceUsageViolation::class.java
    )
    
    .build(
    )
    
    }
    
    override fun onCreate(savedInstanceState: Bundle?)
    {
    
    super.onCreate(savedInstanceState
    )
    
    // ..
    .
    
    }
    
    }
    
    https://developer.android.com/guide/fragments/debugging?hl=en#strictmode
    

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53. penaltyDeath() Ϋϥογϡ
    penaltyListener { violation -> } ηοτͨ͠Ϧεφʔ͕ݺ͹ΕΔ
    penaltyLog() ϩάʢdebug levelʣʹग़ྗ
    ペナルティの種類
    

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54. detectFragmentReuse() FragmentManager ͔Β remove ͞Εͨ͋ͱͷ Fragment Λ࠶ར༻͍ͯ͠Δ͔
    detectFragmentTagUsage() ϨΠΞ΢τXML Ͱ λάΛ࢖͍ͬͯΔ͔
    
    detectRetainInstanceUsage() setRetainInstance() / getRetainInstance() ΛݺΜͰ͍Δ͔
    detectSetUserVisibleHint() setUserVisibleHint() ΛݺΜͰ͍Δ͔
    detectTargetFragmentUsage() setTargetFragment() / getTargetFragment() / getTargetRequestCode() ΛݺΜͰ͍Δ͔
    detectWrongFragmentContainer() FragmentContainerView Ҏ֎ͷ View ʹ Fragment ͕௥Ճ͞Ε͍ͯΔ͔
    検出できる違反の種類
    

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55. Lifecycle
    

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56. [deprecated] @OnLifecycleEvent
    androidx.lifecycle
    • 新しい⽅法 : DefaultLifecycleObserver か LifecycleEventObserver を使う
    

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57. 以前の⽅法
    class MainActivity : FragmentActivity()
    {
    
    override fun onCreate(savedInstanceState: Bundle?)
    {
    
    super.onCreate(savedInstanceState
    )
    
    lifecycle.addObserver(object : LifecycleObserver
    {
    
    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME
    )
    
    fun doSomething(owner: LifecycleOwner)
    {
    
    // do somethin
    g
    
    }
    
    @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY
    )
    
    fun onDestroy(owner: LifecycleOwner)
    {
    
    owner.lifecycle.removeObserver(this
    )
    
    }
    
    }
    )
    
    }
    
    …
    
    }
    

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58. 新しい⽅法
    DefaultLifecycleObserver
    class MainActivity : FragmentActivity()
    {
    
    override fun onCreate(savedInstanceState: Bundle?)
    {
    
    super.onCreate(savedInstanceState
    )
    
    lifecycle.addObserver(object : DefaultLifecycleObserver
    {
    
    override fun onResume(owner: LifecycleOwner)
    {
    
    // do somethin
    g
    
    }
    
    override fun onDestroy(owner: LifecycleOwner)
    {
    
    owner.lifecycle.removeObserver(this
    )
    
    }
    
    }
    )
    
    }
    
    …
    
    }
    Lifecycle.Event.ON_RESUME
    Lifecycle.Event.ON_DESTROY
    

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59. 新しい⽅法
    LifecycleEventObserver
    class MainActivity : FragmentActivity()
    {
    
    override fun onCreate(savedInstanceState: Bundle?)
    {
    
    super.onCreate(savedInstanceState
    )
    
    lifecycle.addObserver(object : LifecycleEventObserver
    {
    
    override fun onStateChanged(owner: LifecycleOwner, event: Lifecycle.Event)
    {
    
    when (event)
    {
    
    Lifecycle.Event.ON_RESUME ->
    {
    
    // do somethin
    g
    
    }
    
    Lifecycle.Event.ON_DESTROY ->
    {
    
    owner.lifecycle.removeObserver(this
    )
    
    }
    
    }
    
    }
    
    }
    )
    
    }
    
    …
    
    }
    

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60. まとめ
    • startActivityForResult() や requestPermission() には ActivityResultContract
    を使う
    • Fragment は書き⽅がいろいろ変わっている
    • Fragment ⽤の StrictMode で違反を簡単に検出できる
    • deprecated になった機能は早め早めに対応しよう
    

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