I patched the MtkSettings2.apk (6.1.3 @sh7411usa version) so that it doesn’t crash when you try to turn on accessibility for Voice Access (or any other apps that were having that issue).
I’ll try to post a guide later for those who want to patch the settings app from other versions.
Settings App (replace the app in /system_ext/priv-app/MtkSettings2/)
Can you detail what you did? I’ll include it in future updates
Sure, I’ll try write it up later today. There were 3 issues that needed to be fixed.
I had ai write it up
In ToggleFeaturePreferenceFragment.onViewCreated(), a PreferenceCategory (key general_categories) is created and configured, but never attached to the fragment’s PreferenceScreen before another preference is added into it. Adding a child to an unattached PreferenceGroup throws a NullPointerException in PreferenceManager.getNextId().
File: smali/com/android/settings/accessibility/ToggleFeaturePreferenceFragment.smali
Method: onViewCreated(Landroid/view/View;Landroid/os/Bundle;)V
Fix: Insert a call to attach the category to the screen (p1) right after it’s titled, before initShortcutPreference is called:
sget v2, Lcom/android/settings/R$string;->accessibility_screen_option:I
invoke-virtual {v0, v2}, Landroidx/preference/Preference;->setTitle(I)V
invoke-virtual {p1, v0}, Landroidx/preference/PreferenceGroup;->addPreference(Landroidx/preference/Preference;)Z
invoke-direct {p0, p2}, Lcom/android/settings/accessibility/ToggleFeaturePreferenceFragment;->initShortcutPreference(Landroid/os/Bundle;)V
(Only the addPreference line is new, the lines around it already exist and are shown for placement reference.)
Cause: Settings classifies every accessibility service into one of 3 fragment types via AccessibilityUtil.getAccessibilityServiceFragmentType(), based on targetSdkVersion and whether the service declares the accessibility-button flag. Voice Access was being classified as “Invisible Toggle” (no switch shown, expects shortcut-only interaction) instead of the normal “Toggle” type.
File: smali/com/android/settings/accessibility/AccessibilityUtil.smali
Method: getAccessibilityServiceFragmentType(Landroid/accessibilityservice/AccessibilityServiceInfo;)I
Fix: Replace the entire method body to always return type 2 (normal Toggle) for every accessibility service:
.method static getAccessibilityServiceFragmentType(Landroid/accessibilityservice/AccessibilityServiceInfo;)I
.registers 5
const/4 v1, 0x2
return v1
.end method
Note: this device has no volume keys, so forcing away the “Volume Shortcut Toggle” classification (type 0) has no downside here.
Cause: Enabling the toggle triggers a tutorial dialog showing the accessibility-shortcut gesture animation. AccessibilityGestureNavigationTutorial.createShortcutNavigationContentView() builds this content based on the device’s navigation mode, and an internal Preconditions.checkArgument() throws IllegalArgumentException: Unexpected tutorial pages size — this device’s nav mode doesn’t produce a page count the check expects.
File: smali/com/android/settings/accessibility/AccessibilityGestureNavigationTutorial.smali
Method: createAccessibilityTutorialDialog(Landroid/content/Context;I)Landroidx/appcompat/app/AlertDialog;
Fix: Delete the 3 lines that build and attach the crashing content view, leaving the dialog’s title/button/creation intact:
Remove:
invoke-static {p0, p1}, Lcom/android/settings/accessibility/AccessibilityGestureNavigationTutorial;->createShortcutNavigationContentView(Landroid/content/Context;I)Landroid/view/View;
move-result-object p0
invoke-virtual {v0, p0}, Landroidx/appcompat/app/AlertDialog$Builder;->setView(Landroid/view/View;)Landroidx/appcompat/app/AlertDialog$Builder;
Resulting method:
.method static createAccessibilityTutorialDialog(Landroid/content/Context;I)Landroidx/appcompat/app/AlertDialog;
.registers 3
new-instance v0, Landroidx/appcompat/app/AlertDialog$Builder;
invoke-direct {v0, p0}, Landroidx/appcompat/app/AlertDialog$Builder;-><init>(Landroid/content/Context;)V
sget p0, Lcom/android/settings/R$string;->accessibility_tutorial_dialog_button:I
sget-object p1, Lcom/android/settings/accessibility/AccessibilityGestureNavigationTutorial;->mOnClickListener:Landroid/content/DialogInterface$OnClickListener;
invoke-virtual {v0, p0, p1}, Landroidx/appcompat/app/AlertDialog$Builder;->setNegativeButton(ILandroid/content/DialogInterface$OnClickListener;)Landroidx/appcompat/app/AlertDialog$Builder;
invoke-virtual {v0}, Landroidx/appcompat/app/AlertDialog$Builder;->create()Landroidx/appcompat/app/AlertDialog;
move-result-object p0
return-object p0
.end method
This produces a minimal dialog (dismiss button only, no tutorial illustration) instead of crashing. onCreateDialog in both ToggleFeaturePreferenceFragment and ToggleAccessibilityServicePreferenceFragment call into this method but don’t need any changes themselves.
Thank you! Very detailed!
Curious though - most of us here used voice access for voice typing and tapping on devices that didn’t otherwise support voice typing and did not have touch screens. Seeing as the F21 has both, why do we need voice access?
Telling it to call someone
Gotcha - so voice commands in a kosher way (you want to avoid google assistant).
Yup, I’m lazy like that, and I like being able to launch it with a physical key. I remapped the menu key ( /system/usr/keylayout/Generic.kl 139 MENU to 139 FOCUS)
Excellent piece of info!