Fix lint errors

app/src/main/java/org/tasks/dialogs/ColorPalettePicker.kt

@@ -79,12 +79,12 @@ class ColorPalettePicker : InjectingDialogFragment() {
         val inflater = LayoutInflater.from(context)
         val view = inflater.inflate(R.layout.dialog_icon_picker, null)
         ButterKnife.bind(this, view)
-        palette = arguments!!.getSerializable(EXTRA_PALETTE) as Palette
+        palette = requireArguments().getSerializable(EXTRA_PALETTE) as Palette
         colors = when (palette) {
             Palette.COLORS -> colorProvider.getThemeColors()
             Palette.ACCENTS -> colorProvider.getAccentColors()
             Palette.LAUNCHERS -> ThemeColor.LAUNCHER_COLORS.map { color ->
-                ThemeColor(context, ContextCompat.getColor(context!!, color))
+                ThemeColor(context, ContextCompat.getColor(requireContext(), color))
             }
             Palette.WIDGET -> colorProvider.getWidgetColors()
         }
@@ -111,7 +111,7 @@ class ColorPalettePicker : InjectingDialogFragment() {
             builder.setNegativeButton(android.R.string.cancel, null)
         } else {
             builder.setPositiveButton(R.string.button_subscribe) { _: DialogInterface?, _: Int ->
-                context?.startActivity(Intent(context!!, PurchaseActivity::class.java))
+                context?.startActivity(Intent(requireContext(), PurchaseActivity::class.java))
             }
         }
         return builder.show()

app/src/main/java/org/tasks/dialogs/ColorWheelPicker.kt

@@ -49,7 +49,7 @@ class ColorWheelPicker : InjectingDialogFragment() {
     override fun inject(component: DialogFragmentComponent) = component.inject(this)
 
     override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
-        selected = savedInstanceState?.getInt(EXTRA_SELECTED) ?: arguments!!.getInt(EXTRA_SELECTED, 0)
+        selected = savedInstanceState?.getInt(EXTRA_SELECTED) ?: requireArguments().getInt(EXTRA_SELECTED, 0)
 
         val button = if (inventory.purchasedThemes()) android.R.string.ok else R.string.button_subscribe
         val builder = ColorPickerDialogBuilder

app/src/main/java/org/tasks/dialogs/DateTimePicker.kt

@@ -124,7 +124,7 @@ class DateTimePicker : InjectingBottomSheetDialogFragment() {
             }
         }
         val timestamp = savedInstanceState?.getLong(EXTRA_SELECTED)
-                ?: arguments!!.getLong(EXTRA_TIMESTAMP)
+                ?: requireArguments().getLong(EXTRA_TIMESTAMP)
         selected = if (timestamp > 0) DateTime(timestamp) else null
 
         return binding.root

app/src/main/java/org/tasks/dialogs/ThemePickerDialog.kt

@@ -57,13 +57,13 @@ class ThemePickerDialog : InjectingDialogFragment() {
     override fun inject(component: DialogFragmentComponent) = component.inject(this)
 
     override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
-        selected = savedInstanceState?.getInt(EXTRA_SELECTED) ?: arguments!!.getInt(EXTRA_SELECTED)
+        selected = savedInstanceState?.getInt(EXTRA_SELECTED) ?: requireArguments().getInt(EXTRA_SELECTED)
         val widget = arguments?.getBoolean(EXTRA_WIDGET) ?: false
         val themes = resources.getStringArray(
             if (widget) R.array.widget_themes else R.array.base_theme_names
         )
 
-        adapter = object : ArrayAdapter<String>(activity!!, R.layout.simple_list_item_single_choice, themes) {
+        adapter = object : ArrayAdapter<String>(requireActivity(), R.layout.simple_list_item_single_choice, themes) {
             override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
                 val view = super.getView(position, convertView, parent)
                 val textColor = if (isAvailable(position)) {
@@ -79,7 +79,7 @@ class ThemePickerDialog : InjectingDialogFragment() {
 
         dialog = dialogBuilder.newDialog()
                 .setTitle(R.string.theme)
-                .setSingleChoiceItems(adapter, arguments!!.getInt(EXTRA_SELECTED)) { _, which ->
+                .setSingleChoiceItems(adapter, requireArguments().getInt(EXTRA_SELECTED)) { _, which ->
                     selected = which
                     if (available()) {
                         deliverResult()

app/src/main/java/org/tasks/injection/InjectingPreferenceFragment.kt

@@ -48,7 +48,7 @@ abstract class InjectingPreferenceFragment : PreferenceFragmentCompat() {
     final override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
         setPreferencesFromResource(getPreferenceXml(), rootKey)
 
-        tintIcons(preferenceScreen, ContextCompat.getColor(context!!, R.color.icon_tint_with_alpha))
+        tintIcons(preferenceScreen, ContextCompat.getColor(requireContext(), R.color.icon_tint_with_alpha))
 
         setupPreferences(savedInstanceState)
     }
@@ -76,7 +76,7 @@ abstract class InjectingPreferenceFragment : PreferenceFragmentCompat() {
 
     protected fun tintColorPreference(resId: Int, tint: Int) {
         val pref = findPreference(resId)
-        pref.icon = DrawableUtil.getWrapped(context!!, R.drawable.color_picker)
+        pref.icon = DrawableUtil.getWrapped(requireContext(), R.drawable.color_picker)
         DrawableUtil.setTint(pref.icon, tint)
     }
 
@@ -117,7 +117,7 @@ abstract class InjectingPreferenceFragment : PreferenceFragmentCompat() {
     abstract fun setupPreferences(savedInstanceState: Bundle?)
 
     protected fun recreate() {
-        activity!!.recreate()
+        requireActivity().recreate()
     }
 
     protected fun findPreference(@StringRes prefId: Int): Preference {

app/src/main/java/org/tasks/preferences/fragments/Advanced.kt

@@ -100,7 +100,7 @@ class Advanced : InjectingPreferenceFragment() {
             if (resultCode == Activity.RESULT_OK) {
                 val uri = data!!.data!!
                 if (AndroidUtilities.atLeastLollipop()) {
-                    context!!.contentResolver
+                    requireContext().contentResolver
                         .takePersistableUriPermission(
                             uri,
                             Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION
@@ -231,7 +231,7 @@ class Advanced : InjectingPreferenceFragment() {
             .newDialog()
             .setMessage(R.string.EPr_delete_task_data_warning)
             .setPositiveButton(R.string.EPr_delete_task_data) { _, _ ->
-                context!!.deleteDatabase(database.name)
+                requireContext().deleteDatabase(database.name)
                 exitProcess(0)
             }
             .setNegativeButton(android.R.string.cancel, null)

app/src/main/java/org/tasks/preferences/fragments/LookAndFeel.kt

@@ -8,9 +8,7 @@ import android.content.pm.PackageManager
 import android.content.res.Configuration
 import android.os.Bundle
 import android.os.Handler
-import android.widget.Toast
 import androidx.annotation.StringRes
-import androidx.preference.ListPreference
 import androidx.preference.Preference
 import com.google.common.base.Strings
 import com.todoroo.andlib.utility.AndroidUtilities.atLeastLollipop
@@ -25,7 +23,6 @@ import org.tasks.dialogs.ColorPalettePicker
 import org.tasks.dialogs.ColorPalettePicker.Companion.newColorPalette
 import org.tasks.dialogs.ColorPickerAdapter
 import org.tasks.dialogs.ColorWheelPicker
-import org.tasks.dialogs.MyTimePickerDialog.newTimePicker
 import org.tasks.dialogs.ThemePickerDialog
 import org.tasks.dialogs.ThemePickerDialog.Companion.newThemePickerDialog
 import org.tasks.gtasks.PlayServices
@@ -41,14 +38,10 @@ import org.tasks.themes.ThemeBase.DEFAULT_BASE_THEME
 import org.tasks.themes.ThemeBase.EXTRA_THEME_OVERRIDE
 import org.tasks.themes.ThemeColor
 import org.tasks.themes.ThemeColor.getLauncherColor
-import org.tasks.time.DateTime
 import org.tasks.ui.ChipProvider
 import org.tasks.ui.NavigationDrawerFragment.REQUEST_PURCHASE
 import org.tasks.ui.SingleCheckedArrayAdapter
-import org.tasks.ui.TimePreference
 import org.tasks.ui.Toaster
-import org.threeten.bp.DayOfWeek
-import org.threeten.bp.format.TextStyle
 import javax.inject.Inject
 
 private const val REQUEST_THEME_PICKER = 10001
@@ -177,7 +170,7 @@ class LookAndFeel : InjectingPreferenceFragment() {
     private fun setupLocationPickers() {
         val choices =
             listOf(getString(R.string.map_provider_mapbox), getString(R.string.map_provider_google))
-        val singleCheckedArrayAdapter = SingleCheckedArrayAdapter(context!!, choices, themeAccent)
+        val singleCheckedArrayAdapter = SingleCheckedArrayAdapter(requireContext(), choices, themeAccent)
         val mapProviderPreference = findPreference(R.string.p_map_provider)
         mapProviderPreference.onPreferenceClickListener = Preference.OnPreferenceClickListener {
             dialogBuilder
@@ -351,7 +344,7 @@ class LookAndFeel : InjectingPreferenceFragment() {
         val packageManager: PackageManager? = context?.packageManager
         for (i in ThemeColor.LAUNCHERS.indices) {
             val componentName = ComponentName(
-                context!!,
+                requireContext(),
                 "com.todoroo.astrid.activity.TaskListActivity" + ThemeColor.LAUNCHERS[i]
             )
             packageManager?.setComponentEnabledSetting(

app/src/main/java/org/tasks/preferences/fragments/Notifications.kt

@@ -144,7 +144,7 @@ class Notifications : InjectingPreferenceFragment() {
 
     private fun checkBatteryOptimizations() {
         if (atLeastMarshmallow()) {
-            val powerManager = context!!.getSystemService(POWER_SERVICE) as PowerManager
+            val powerManager = requireContext().getSystemService(POWER_SERVICE) as PowerManager
             findPreference(R.string.disable_battery_optimizations).isVisible =
                 !powerManager.isIgnoringBatteryOptimizations(getString(R.string.app_package))
         }

app/src/main/java/org/tasks/preferences/fragments/ScrollableWidget.kt

@@ -54,7 +54,7 @@ class ScrollableWidget : InjectingPreferenceFragment() {
     override fun getPreferenceXml() = R.xml.preferences_widget
 
     override fun setupPreferences(savedInstanceState: Bundle?) {
-        appWidgetId = arguments!!.getInt(EXTRA_WIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID)
+        appWidgetId = requireArguments().getInt(EXTRA_WIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID)
         widgetPreferences = WidgetPreferences(context, preferences, appWidgetId)
 
         val row = setupSlider(R.string.p_widget_opacity, 100)

app/src/main/java/org/tasks/preferences/fragments/TaskerListNotification.kt

@@ -72,7 +72,7 @@ class TaskerListNotification : InjectingPreferenceFragment() {
         } else if (requestCode == REQUEST_SUBSCRIPTION) {
             if (!inventory.purchasedTasker()) {
                 cancelled = true
-                activity!!.finish()
+                requireActivity().finish()
             }
         } else {
             super.onActivityResult(requestCode, resultCode, data)