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| package io.github.hkusu.sample.ui | |
| import android.os.Bundle | |
| import android.view.View | |
| import androidx.fragment.app.Fragment | |
| import io.github.hkusu.sample.databinding.MainFragmentBinding | |
| class MainFragment : Fragment(R.layout.main_fragment) { | |
| private val binding: MainFragmentBinding by viewBinding() | |
| override fun onViewCreated(view: View, savedInstanceState: Bundle?) { | |
| super.onViewCreated(view, savedInstanceState) | |
| binding.message.text = "テストテスト" | |
| } | |
| override fun onDestroy() { | |
| super.onDestroy() | |
| // この時点でFragment#getView()は死んでいる | |
| safeViewBinding { | |
| binding.message.text = "安全！" | |
| } | |
| } | |
| } |
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| package io.github.hkusu.sample.ext | |
| import android.util.Log | |
| import android.view.ViewGroup | |
| import androidx.appcompat.app.AppCompatActivity | |
| import androidx.core.view.get | |
| import androidx.databinding.DataBindingUtil | |
| import androidx.databinding.ViewDataBinding | |
| import androidx.fragment.app.Fragment | |
| import kotlin.properties.ReadOnlyProperty | |
| import kotlin.reflect.KProperty | |
| // ref: https://satoshun.github.io/2020/01/fragment-view-memory-leak/ | |
| // https://satoshun.github.io/2019/04/jetpack-coroutine-support/ | |
| fun <T : ViewDataBinding> AppCompatActivity.viewBinding(): ReadOnlyProperty<AppCompatActivity, T> { | |
| return object : ReadOnlyProperty<AppCompatActivity, T> { | |
| override fun getValue(thisRef: AppCompatActivity, property: KProperty<*>): T { | |
| val view = thisRef.findViewById<ViewGroup>(android.R.id.content)[0] | |
| val binding = DataBindingUtil.bind<T>(view)!! | |
| binding.lifecycleOwner = thisRef | |
| return binding | |
| } | |
| } | |
| } | |
| fun <T : ViewDataBinding> Fragment.viewBinding(): ReadOnlyProperty<Fragment, T> { | |
| return object : ReadOnlyProperty<Fragment, T> { | |
| override fun getValue(thisRef: Fragment, property: KProperty<*>): T { | |
| val view = thisRef.view ?: throw FragmentViewNotFoundException() | |
| val binding = DataBindingUtil.bind<T>(view)!! | |
| binding.lifecycleOwner = thisRef.viewLifecycleOwner | |
| return binding | |
| } | |
| } | |
| } | |
| // Fragment.viewBinding() 用 | |
| class FragmentViewNotFoundException : Exception("Fragment#getView() returned null.") | |
| // Fragment.viewBinding() 用。コールバックや遅延実行等でonDestroyView()後にBindingを触る可能性がある場合に利用する | |
| inline fun Fragment.safeViewBinding(block: () -> Unit) { | |
| try { | |
| block.invoke() | |
| } catch (e: FragmentViewNotFoundException) { | |
| Log.w(this::class.java.simpleName, e.message!!) | |
| } | |
| } | |
| // そもそも binding を Nullable にして安全に扱いたい場合は Fragment.viewBinding() の代わりにこちらを利用する | |
| fun <T : ViewDataBinding> Fragment.safeViewBinding(): ReadOnlyProperty<Fragment, T?> { | |
| return object : ReadOnlyProperty<Fragment, T?> { | |
| override fun getValue(thisRef: Fragment, property: KProperty<*>): T? { | |
| val view = thisRef.view ?: return null | |
| val binding = DataBindingUtil.bind<T>(view)!! | |
| binding.lifecycleOwner = thisRef.viewLifecycleOwner | |
| return binding | |
| } | |
| } | |
| } |
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