Compose Accessibility Testing: Build Inclusive Jetpack Compose Apps

Accessibility is a critical aspect of modern Android app development. Ensuring that applications are usable by individuals with disabilities is not only ethical but also broadens the potential user base. Jetpack Compose, Android’s modern UI toolkit, provides various tools and strategies to build accessible apps. This blog post delves into how to conduct accessibility testing in Jetpack Compose applications.

What is Accessibility Testing?

Accessibility testing involves evaluating an application to ensure it can be used effectively by people with disabilities, including visual, auditory, motor, and cognitive impairments. It includes verifying that the app adheres to accessibility standards like WCAG (Web Content Accessibility Guidelines) and platform-specific guidelines, such as those provided by Android.

Why is Accessibility Testing Important?

• Inclusivity: Provides a better user experience for everyone, regardless of their abilities.
• Legal Compliance: Adheres to legal requirements like the Americans with Disabilities Act (ADA).
• Enhanced User Experience: Improves the overall usability and satisfaction for all users.
• Wider Audience: Opens up the application to a broader range of potential users.

How to Conduct Accessibility Testing in Jetpack Compose

Testing accessibility in Jetpack Compose involves several steps and considerations. Here’s a comprehensive guide:

Step 1: Understand Accessibility Modifiers

Jetpack Compose offers accessibility modifiers that can be used to provide information to assistive technologies like screen readers. Key modifiers include:

• semantics: Used to associate accessibility information with composables.
• contentDescription: Provides a textual description of the UI element.
• onClickLabel: Describes the action performed when an element is clicked.
• stateDescription: Indicates the state of a UI element (e.g., checked, expanded).

Example using contentDescription and onClickLabel:

import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.padding
import androidx.compose.material.Icon
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.Add
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.semantics.contentDescription
import androidx.compose.ui.semantics.onClick
import androidx.compose.ui.semantics.semantics
import androidx.compose.ui.unit.dp

@Composable
fun AccessibleButton() {
    Icon(
        imageVector = Icons.Filled.Add,
        contentDescription = "Add item",
        modifier = Modifier
            .padding(16.dp)
            .clickable(
                onClick = {}
            )
            .semantics {
                contentDescription = "Add item to cart"
                onClick(label = "Add to cart") {
                    // Perform the action
                    true
                }
            }
    )
}

In this example:

• contentDescription provides a description for screen readers.
• onClickLabel offers a descriptive label for the click action.
• The semantics modifier combines these properties to enhance accessibility.

Step 2: Use the Accessibility Scanner

The Accessibility Scanner is an Android app developed by Google that helps identify accessibility issues. It suggests improvements to enhance the accessibility of the app.

To use the Accessibility Scanner:

1. Install the Accessibility Scanner: Download it from the Google Play Store.
2. Enable the Scanner: Go to Settings > Accessibility > Accessibility Scanner and turn it on.
3. Use the Scanner in Your App: Open your app and tap the Accessibility Scanner button to initiate the scan. The scanner highlights potential issues and provides suggestions.

Step 3: Manual Testing with Screen Readers

Manual testing with screen readers is essential to understanding the user experience for individuals with visual impairments.

Steps for manual testing with TalkBack (Android’s built-in screen reader):

1. Enable TalkBack: Go to Settings > Accessibility > TalkBack and turn it on.
2. Navigate Through Your App: Use gestures to navigate through your app and listen to how TalkBack describes the UI elements.
3. Verify Descriptions: Ensure that contentDescription and other accessibility properties are correctly read and provide meaningful information.

Common issues to look for during manual testing:

• Missing Descriptions: Elements without descriptions can be confusing.
• Incorrect Order: Ensure elements are read in a logical order.
• Redundant Information: Avoid repeating information unnecessarily.
• Lack of State Information: Elements that change state (e.g., checkboxes) should clearly indicate their current state.

Step 4: Using Compose UI Testing with Accessibility

Jetpack Compose provides testing APIs that allow you to verify accessibility properties programmatically.

Add the necessary dependencies in your build.gradle file:

dependencies {
    androidTestImplementation("androidx.compose.ui:ui-test-junit4:1.6.1")
    debugImplementation("androidx.compose.ui:ui-tooling:1.6.1")
    debugImplementation("androidx.compose.ui:ui-test-manifest:1.6.1")
}

Create an accessibility test to verify the contentDescription of a composable:

import androidx.compose.ui.test.junit4.createComposeRule
import androidx.compose.ui.test.onNodeWithContentDescription
import org.junit.Rule
import org.junit.Test

class AccessibilityTest {

    @get:Rule
    val composeTestRule = createComposeRule()

    @Test
    fun testAccessibleButtonContentDescription() {
        composeTestRule.setContent {
            AccessibleButton()
        }

        composeTestRule.onNodeWithContentDescription("Add item to cart").assertExists()
    }
}

In this test:

• createComposeRule initializes the Compose testing environment.
• setContent sets the composable to be tested.
• onNodeWithContentDescription finds a node with the specified content description.
• assertExists verifies that the node exists, ensuring that the content description is properly set.

Step 5: Dynamic Content and Accessibility

When dealing with dynamic content, ensure that accessibility information is updated accordingly. For example, if the content of a text field changes, update the contentDescription or use LiveRegion to announce changes to the screen reader.

import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.padding
import androidx.compose.material.Button
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.semantics.LiveRegionMode
import androidx.compose.ui.semantics.contentDescription
import androidx.compose.ui.semantics.liveRegion
import androidx.compose.ui.semantics.semantics
import androidx.compose.ui.unit.dp

@Composable
fun DynamicContentExample() {
    val content = remember { mutableStateOf("Initial content") }

    Column(modifier = Modifier.padding(16.dp)) {
        Text(
            text = content.value,
            modifier = Modifier
                .padding(bottom = 8.dp)
                .semantics {
                    contentDescription = content.value
                    liveRegion = LiveRegionMode.Polite // Announce changes politely
                }
        )
        Button(onClick = { content.value = "Updated content" }) {
            Text(text = "Update Content")
        }
    }
}

In this example:

• The liveRegion property is set to LiveRegionMode.Polite to announce content changes to the screen reader politely.
• The contentDescription is updated whenever the content changes.

Best Practices for Accessibility in Jetpack Compose

• Use Semantic Properties: Always provide meaningful contentDescription, onClickLabel, and stateDescription.
• Test with Screen Readers: Regularly test your app with TalkBack to understand the user experience for visually impaired users.
• Automate Accessibility Testing: Incorporate accessibility tests into your CI/CD pipeline to catch issues early.
• Follow Material Design Accessibility Guidelines: Adhere to Android’s accessibility guidelines to create a consistent and accessible user experience.
• Provide Sufficient Contrast: Ensure sufficient color contrast between text and background for users with low vision.
• Use Large Touch Targets: Make interactive elements large enough for easy interaction, especially for users with motor impairments.
• Consider Keyboard Navigation: Ensure your app can be navigated using a keyboard for users who cannot use touch input.

Conclusion

Accessibility testing in Jetpack Compose is a vital part of creating inclusive and user-friendly Android applications. By understanding accessibility modifiers, utilizing tools like the Accessibility Scanner, and conducting manual testing with screen readers, developers can build apps that are accessible to everyone. Incorporating automated accessibility tests into the development process ensures ongoing accessibility compliance. By following best practices and staying informed about accessibility guidelines, developers can make a significant positive impact on the user experience for people with disabilities.