android - AppCompatDelegate#setDefaultNightMode() 从 API 23 的 SettingsActivity 返回后导致 MainActivity 冻结

Question

我已经为我的应用程序实现了一个日/夜主题，并在我的 PreferencesActivity/Fragment 中添加了一个 ListPreference 以在那里进行更改。对于 API 24+，一切正常，但不适用于 API 23（这是我的最低要求）。

问题：当在 Preferences 中选择不同的主题，然后返回 MainActivity 时，它会应用新主题，然后冻结。

我在日志中看到，MainActivity 正在重新创建自己，再次经历生命周期，但在最后一个 onResume() 之后调用 onPause()。

从 MainActivity 启动 PreferencesActivity：

06-02 23:29:17.795 11783-11783/com.package D/MainActivity: onPause()
06-02 23:29:17.815 11783-11783/com.package D/PreferencesActivity: onResume()
06-02 23:29:18.299 11783-11783/com.package D/RosterParentFragment: saving instance state with 2019-06

切换主题：

06-02 23:29:29.853 11783-11783/com.package D/PreferencesFragment: Preference changed with key KEY_DAY_NIGHT_MODE
06-02 23:29:29.856 11783-11783/com.package D/PreferencesActivity: onPause()
06-02 23:29:29.870 11783-11783/com.package D/PreferencesActivity: onResume()

切换回 MainActivity（通过后按或主页 <-）：

06-02 23:32:26.209 11783-11783/com.package D/MainActivity: onResume()
06-02 23:32:26.247 11783-11783/com.package D/MainActivity: onPause()
06-02 23:32:26.248 11783-11783/com.package D/RosterParentFragment: saving instance state with 2019-06
06-02 23:32:26.254 11783-11783/com.package D/RosterParentFragment: onCreate()
06-02 23:32:26.254 11783-11783/com.package D/RosterParentFragment: savedInstanceState == Bundle[{android:support:fragments=androidx.fragment.app.FragmentManagerState@9a98da, androidx.lifecycle.BundlableSavedStateRegistry.key=Bundle[{}], SelectedYearMonth=2019-06, android:view_state={2131296460=FragmentPager.SavedState{f01b10b position=113}}}]
06-02 23:32:26.254 11783-11783/com.package D/MainActivity: onCreate()
06-02 23:32:26.266 11783-11783/com.package D/MainActivity: savedInstanceState NOT null
06-02 23:32:26.266 11783-11783/com.package D/MainActivity: got fragment from fragment manager
06-02 23:32:26.268 11783-11783/com.package D/RosterParentFragment: onCreateView()
06-02 23:32:26.353 11783-11783/com.package D/MainActivity: onResume()
06-02 23:32:26.366 11783-11783/com.package D/MainActivity: onPause()

（而这最后一个 onPause() 似乎是罪魁祸首 - 没有为 API 24+ 这样做。）

之后，触摸屏幕会给出一个

W/ViewRootImpl: Dropping event due to no window focus: MotionEvent

警告并离开应用程序（例如主页按钮）给出

Performing pause of activity that is not resumed

适用于 API 24+。有任何想法吗？

class PreferencesFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedPreferenceChangeListener {
    private val dayNightMode: ListPreference by lazy { findPreference<ListPreference>(Preferences.Key.DAY_NIGHT_MODE)!! }
    private val dayNightModeEntries = App.instance.applicationContext.resources.getStringArray(R.array.preferences_theme_entries)
    private val dayNightModeValues = App.instance.applicationContext.resources.getStringArray(R.array.preferences_theme_values)

    override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences?, key: String?) {
        when (key) {
            Preferences.Key.DAY_NIGHT_MODE -> {       
                AppCompatDelegate
                    .setDefaultNightMode(
                        Preferences.getCurrentDayNightMode())
            }
        }
    }

    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.preferences, rootKey)
    }

    override fun onStart() {
        super.onStart()
        Preferences.default()
            .registerOnSharedPreferenceChangeListener(this)
    }

    override fun onStop() {
        Preferences.default()
            .unregisterOnSharedPreferenceChangeListener(this)
        super.onStop()
    }
}

object Preferences {
    object Key {
        val DAY_NIGHT_MODE: String = "KEY_DAY_NIGHT_MODE"
    }

    fun default(): SharedPreferences = PreferenceManager
       .getDefaultSharedPreferences(App.instance.applicationContext)

    fun getCurrentDayNightMode(): Int {
        if (default().getString(Key.DAY_NIGHT_MODE, null) == null) {
            // no DayNightMode selected - setting to MODE_NIGHT_FOLLOW_SYSTEM
            default().setValue(Key.DAY_NIGHT_MODE, MODE_NIGHT_FOLLOW_SYSTEM.toString())
        }
        return default().getString(Key.DAY_NIGHT_MODE, null)!!.toInt()
    }

    fun setCurrentDayNightMode(mode: Int) {
        AppCompatDelegate.setDefaultNightMode(mode)
        default().setValue(Key.DAY_NIGHT_MODE, mode.toString())
    }
}

标签： androidthemes