ADFA-4072: treat system back button as Cancel in settings dialogs

app/src/main/java/com/itsaky/androidide/preferences/editorPrefExts.kt

@@ -131,9 +131,6 @@ private class TabSize(
   override val tooltipTag: String = TooltipTag.PREFS_EDITOR,
 ) : SingleChoicePreference() {
 
-  @IgnoredOnParcel
-  override val dialogCancellable = true
-
   @IgnoredOnParcel
   private val tabSizes = intArrayOf(2, 4, 6, 8)
 

app/src/main/java/com/itsaky/androidide/preferences/generalPrefExts.kt

@@ -78,9 +78,6 @@ class UiMode(
   override val icon: Int? = R.drawable.ic_ui_mode
 ) : SingleChoicePreference() {
 
-  @IgnoredOnParcel
-  override val dialogCancellable = true
-
   @IgnoredOnParcel
   override val tooltipTag: String = PREFS_GENERAL
 

app/src/main/java/com/itsaky/androidide/preferences/xmlPrefExts.kt

@@ -21,7 +21,6 @@ import androidx.preference.Preference
 import com.itsaky.androidide.idetooltips.TooltipTag
 import com.itsaky.androidide.preferences.internal.XmlPreferences
 import com.itsaky.androidide.resources.R.string
-import kotlinx.parcelize.IgnoredOnParcel
 import kotlinx.parcelize.Parcelize
 import org.eclipse.lemminx.dom.builder.EmptyElements
 
@@ -212,9 +211,6 @@ private class EmptyElementsBehavior(
   override val tooltipTag: String = TooltipTag.PREFS_EDITOR_XML,
 ) : SingleChoicePreference() {
 
-  @IgnoredOnParcel
-  override val dialogCancellable = true
-
   override fun getEntries(preference: Preference): Array<PreferenceChoices.Entry> {
     val entries = EmptyElements.entries
     val currentBehavior = EmptyElements.valueOf(XmlPreferences.emptyElementsBehavior)

preferences/src/main/java/com/itsaky/androidide/preferences/ChoiceBasedDialogPreference.kt

@@ -72,4 +72,8 @@ abstract class ChoiceBasedDialogPreference : DialogPreference(), PreferenceChoic
   }
 
   override fun onChoicesCancelled(preference: Preference) {}
+
+  final override fun onDialogCancelled(preference: Preference) {
+    onChoicesCancelled(preference)
+  }
 }

preferences/src/main/java/com/itsaky/androidide/preferences/DialogPreference.kt

@@ -34,14 +34,15 @@ abstract class DialogPreference : SimplePreference() {
     get() = this.title
 
   open val dialogMessage: Int? = null
-  open val dialogCancellable: Boolean = false
+  open val dialogCancellable: Boolean = true
   open val tooltipTag: String = ""
 
   override fun onPreferenceClick(preference: Preference): Boolean {
     val dialog = DialogUtils.newMaterialDialogBuilder(preference.context)
     dialog.setTitle(this.dialogTitle)
     dialogMessage?.let { dialog.setMessage(it) }
     dialog.setCancelable(this.dialogCancellable)
+    dialog.setOnCancelListener { onDialogCancelled(preference) }
     onConfigureDialog(preference, dialog)
     val alertDialog = dialog.create()
     alertDialog.show()
@@ -57,4 +58,12 @@ abstract class DialogPreference : SimplePreference() {
   protected open fun onConfigureDialog(preference: Preference,
     dialog: MaterialAlertDialogBuilder) {
   }
+
+  /**
+   * Called when the dialog is cancelled by the user (e.g. the system back button), as opposed to
+   * being dismissed by an action button. The default behaviour discards any unconfirmed changes,
+   * matching the dialog's cancel button.
+   */
+  protected open fun onDialogCancelled(preference: Preference) {
+  }
 }