Android accessibility

Accessibility /ˈapps for everybody/ Android apps that are usable by everyone. Make no assumptions about the user.

AppFoundry appfoundry.be

No content

No content

No content

Why?

Assumptions Sight See the screen Mobility Touch the screen Audio Hear Speech Interact

Accessibility? 2 % visual impairment 8 % men color blind 0,1 % blind 8 out of 10 with visual impairment or blindness are older than 65

Accessibility? up to 20 % motor impairment Permanent Parkinson’s Tremor … Situational Injury … Hands busy

Accessibility services Talkback Screen reader Brailleback Braille display Switch Access Control by switch Voice Access Interact

Brailleback

Switch Access

Voice access Voice Assistant High-level voice commands Accessibility Low-level commands Device control Scrolling, clicking, text editing

Android - iOS

Improve user experience for accessibility

Color blindness Normal vision Deuteranopia Protanopia Tritanopia

Contrast

Color correction Accessibility options Color simulation Developer options

Color contrast WCAG : background - foreground : 4.5 contrast ratio

Android Accessibility features Large Text Magnification Gestures High Contrast Text Color inversion Color correction Caption support App developer Text size = sp Layouts = responsive

No content

Content description

Content description

Meaningful image

Meaningful image

Decorative image

Decorative image

Content description

Content description

States public void setIconAccessibilityText(boolean isFavorite, String teamName) {
 favoriteTeamMenuItem.setTitle(
 isFavorite ?
 ”defavoritise {teamName}” :
 ”mark {teamName} as favorite”;
 }

AccessibilityLiveRegion

AccessibilityLiveRegion

AnnounceForAccessibility private void makeViewVisible() {
 view.setVisibility(View.VISIBLE);
 view.announceForAccessibility(getString(R.string.acc));
 }

AnnounceForAccessibility private void makeViewVisible() {
 view.setVisibility(View.VISIBLE);
 view.announceForAccessibility(getString(R.string.acc));
 }

AnnounceForAccessibility private void setFavoriteListener(final Team team, final boolean isFavorite) {
 view.setOnClickListener(new View.OnClickListener() {
 
 @Override
 public void onClick(View v) {
 teamListener.onTeamClicked(team);
 String announcement = isFavorite
 ? "Removed " + team.displayTitle() + " from favourites"
 : "Added " + team.displayTitle() + " to favourites";
 view.announceForAccessibility(announcement);
 }
 
 });
 }

AnnounceForAccessibility private void setFavoriteListener(final Team team, final boolean isFavorite) {
 view.setOnClickListener(new View.OnClickListener() {
 
 @Override
 public void onClick(View v) {
 teamListener.onTeamClicked(team);
 String announcement = isFavorite
 ? "Removed " + team.displayTitle() + " from favourites"
 : "Added " + team.displayTitle() + " to favourites";
 view.announceForAccessibility(announcement);
 }
 
 });
 }

Control focus order 
 
 
 
 


Control focus order 
 
 
 
 


Filter / change if necessary

Ads ☹ No Ads Accessibility services detected

Talkback detection public boolean isAccessibilityEnabled() { 
 final AccessibilityManager am = (AccessibilityManager) context.getSystemService(Context.ACCESSIBILITY_SERVICE); 
 boolean isAccessibilityEnabled = am.isEnabled();
 boolean isExploreByTouchEnabled = am.isTouchExplorationEnabled(); 
 return isAccessibilityEnabled && isExploreByTouchEnabled;
 }

Talkback detection public boolean isAccessibilityEnabled() {
 final AccessibilityManager am = (AccessibilityManager) context.getSystemService(Context.ACCESSIBILITY_SERVICE); 
 boolean isAccessibilityEnabled = am.isEnabled();
 boolean isExploreByTouchEnabled = am.isTouchExplorationEnabled(); 
 boolean isSpokenFeedbackEnabled = isSpokenFeedbackEnabled(am);
 return isAccessibilityEnabled && isExploreByTouchEnabled && isSpokenFeedbackEnabled;
 } 
 
 /**
 * Check whether 'spoken feedback' services are enabled.
 */
 private boolean isSpokenFeedbackEnabled(final AccessibilityManager am) {
 List enabledSpokenFeedbackServices = am.getEnabledAccessibilityServiceList(AccessibilityServiceInfo.FEEDBACK_SPOKEN); 
 return !enabledSpokenFeedbackServices.isEmpty();
 }

Content description good / meaningful texts

Meaningful description private void setAccessibilityText(final TeamInfo teamInfo) {
 String accessibilityText;
 if (teamInfo.coaches().isEmpty()) {
 accessibilityText = getString(R.string.no_trainer_acc, teamInfo.teamName());
 } else {
 List trainerNames = getTrainerNames(teamInfo.coaches());
 
 Joiner joiner = Joiner.on(andStr).skipNulls();
 String concatTrainers = joiner.join(trainerNames);
 accessibilityText = getQuantityString(R.plurals.trainer_acc, teamInfo.coaches().size(), teamInfo.teamName(), concatTrainers);
 }
 
 getItemView().setContentDescription(accessibilityText);
 }

Help from your backend

No content

No content

Custom views

Custom actions

MatchView public interface MatchListener {
 
 void onMatchClicked(Match match);
 
 void onMatchComment(Match match);
 
 void onMatchShare(Match match);
 
 void onMatchLiked(Match match);
 }

No content

Don’t descend into view android:importantForAccessibility="noHideDescendants"

DIY public void showMatch(final Match match, final MatchListener listener) {
 …
 
 setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View view) {
 if (isAccessibilityEnabled) {
 showCustomActions(match);
 } else {
 listener.onMatchClicked(match);
 }
 }
 });

No content

No content

Accessibility delegate public static class MatchAccessibilityDelegate extends AccessibilityDelegateCompat {
 
 private final Match match;
 private final MatchListener listener;
 
 public MatchAccessibilityDelegate(final Match match, final MatchListener listener) {
 this.match = match;
 this.listener = listener;
 }
 
 @Override
 public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCompat info) {
 super.onInitializeAccessibilityNodeInfo(host, info);
 info.addAction(new AccessibilityNodeInfoCompat.AccessibilityActionCompat(R.id.comment, "Comment"));
 info.addAction(new AccessibilityNodeInfoCompat.AccessibilityActionCompat(R.id.share, "Share"));
 …
 }
 
 @Override
 public boolean performAccessibilityAction(View host, int action, Bundle args) {
 switch (action) {
 case R.id.comment:
 listener.onMatchComment(match);
 return true;
 case R.id.share:
 listener.onMatchShare(match);
 return true;
 …
 return true;


Accessibility delegate public static class MatchAccessibilityDelegate extends AccessibilityDelegateCompat {
 
 private final Match match;
 private final MatchListener listener;
 
 public MatchAccessibilityDelegate(final Match match, final MatchListener listener) {
 this.match = match;
 this.listener = listener;
 }
 
 @Override
 public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCompat info) {
 super.onInitializeAccessibilityNodeInfo(host, info);
 info.addAction(new AccessibilityNodeInfoCompat.AccessibilityActionCompat(R.id.comment, "Comment"));
 info.addAction(new AccessibilityNodeInfoCompat.AccessibilityActionCompat(R.id.share, "Share"));
 …
 }
 
 @Override
 public boolean performAccessibilityAction(View host, int action, Bundle args) {
 switch (action) {
 case R.id.comment:
 listener.onMatchComment(match);
 return true;
 case R.id.share:
 listener.onMatchShare(match);
 return true;
 …


Accessibility delegate public void showMatch(final Match match, final MatchListener listener) {
 …
 
 ViewCompat.setAccessibilityDelegate(this, new MatchAccessibilityDelegate(match, listener));
 
 …

No content

Testing

Manual testing

No content

Talkback basics Touch to explore Advance through elements (swipe left - right) Double tap selection Gestures for Back, Home, Context menus, …

Accessibility scanner

No content

No content

No content

No content

No content

Code scanning (Lint)

No content

No content

Lint rules lintOptions { abortOnError true }

Instrumentation tests

Espresso - Accessibility @Test
 public void testPlayStopButtonContentDescription() {
 final ViewInteraction playButtonInteraction = onView(withId(R.id.play_button));
 playButtonInteraction.check(matches(withContentDescription("Play")));
 
 playButtonInteraction.perform(click());
 playButtonInteraction.check(matches(withContentDescription("Stop")));
 }

Espresso - Accessibility androidTestCompile 'com.android.support.test.espresso:espresso-contrib:2.2.2' @Before
 public void setUp() {
 AccessibilityChecks.enable();
 }

No content

Accessibility checks com..…AccessibilityViewCheckException: There were 2 accessibility errors: AppCompatImageButton{id=2131427416, res-name=imageButton1, visibility=VISIBLE, width=144, height=132, has- focus=true, has-focusable=true, has-window-focus=false, is-clickable=true, is-enabled=true, is- focused=true, is-focusable=true, is-layout-requested=false, is-selected=false, root-is-layout- requested=false, has-input-connection=false, x=48.0, y=48.0}: View falls below the minimum recommended size for touch targets. Minimum touch target size is 48x48dp. Actual size is 48.0x44.0dp (screen density is 3.0)., AppCompatImageButton{id=2131427416, res-name=imageButton1, visibility=VISIBLE, width=144, height=132, has- focus=true, has-focusable=true, has-window-focus=false, is-clickable=true, is-enabled=true, is- focused=true, is-focusable=true, is-layout-requested=false, is-selected=false, root-is-layout- requested=false, has-input-connection=false, x=48.0, y=48.0}: View is missing speakable text needed for a screen reader at … at android.support.test.espresso.contrib.AccessibilityChecks$2.check(AccessibilityChecks.java:58) at android.support.test.espresso.action.ViewActions$1.perform(ViewActions.java:131) … at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

Android Testing Support Library https://developer.android.com/guide/topics/ui/accessibility

Sample github.com/filipmaelbrancke/AndroidAccessibility Accessibility sample Sample used in this presentation: Custom Actions Espresso Test

Resources Accessibility Testing Checklist https://developer.android.com/training/accessibility/testing.html Google’s Accessibility Test Framework github.com/google/Accessibility-Test-Framework-for-Android Espresso Accessibility Checking google.github.io/android-testing-support-library/docs/accesibility-checking/ Talkback Gestures support.google.com/accessibility/android/answer/6151827?hl=en

+ accessibility + accessibility

No content

Questions? Filip Maelbrancke Consultant @ AppFoundry fi[email protected] @fmaelbrancke