Samsung unveils the Z Fold8 Ultra, a reimagined Z Fold8, and intelligent eyewear at Galaxy Unpacked in London

Introduction

Samsung's recent Galaxy Unpacked event showcased several innovative foldable devices, including the Galaxy Z Fold8 Ultra and Z Flip8. These devices feature advanced display technologies, new form factors, and enhanced software integration. In this tutorial, we'll explore how to work with Samsung's foldable device APIs and development tools to create responsive applications that adapt to different screen states. We'll focus on building a sample application that responds to foldable device states using Samsung's DeX and foldable APIs.

Prerequisites

• Basic understanding of Android development
• Android Studio installed
• Access to a Samsung foldable device or Android emulator with foldable support
• Basic knowledge of Kotlin or Java

Why these prerequisites matter: Android Studio provides the development environment necessary for building Android applications. A foldable device or emulator is essential to test the responsive behavior of our application. Understanding Android development concepts is crucial for implementing the foldable-specific APIs.

Step-by-step Instructions

1. Set Up Your Development Environment

First, ensure you have Android Studio installed with the latest SDK. Create a new Android project with API level 21 or higher to support foldable features.

dependencies {
    implementation 'androidx.window:window:1.0.0'
    implementation 'androidx.window:window-java:1.0.0'
}

Why this step: The Android Windowing Library provides APIs for handling window states and screen configurations, which is essential for foldable device support.

2. Configure Manifest Permissions

Add the necessary permissions and features to your AndroidManifest.xml file:

<uses-feature
    android:name="android.software.foldable"
    android:required="false" />

<uses-feature
    android:name="android.software.foldable.hardware"
    android:required="false" />

Why this step: These declarations inform the system about your app's support for foldable hardware, enabling proper feature detection and handling.

3. Implement Foldable State Detection

Create a class to detect and respond to different foldable states:

class FoldableStateDetector {
    fun detectFoldableState(context: Context): String {
        val windowMetricsCalculator = WindowMetricsCalculator.getOrCreate()
        val windowMetrics = windowMetricsCalculator.computeCurrentWindowMetrics(context as Activity)
        val bounds = windowMetrics.bounds
        
        val isFolded = bounds.width() < bounds.height()
        val isHalfFolded = bounds.width() == bounds.height()
        val isFullyOpen = bounds.width() > bounds.height()
        
        return when {
            isFolded -> "Folded"
            isHalfFolded -> "Half Folded"
            isFullyOpen -> "Fully Open"
            else -> "Unknown"
        }
    }
}

Why this step: This detection logic allows your application to understand the current physical state of the foldable device, enabling dynamic UI adjustments.

4. Create Responsive Layouts

Design layouts that adapt to different screen states:

<!-- res/layout/activity_main.xml -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/main_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    
    <TextView
        android:id="@+id/status_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Detecting device state..." />
        
    <FrameLayout
        android:id="@+id/content_area"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />
</LinearLayout>

Why this step: Responsive layouts ensure that your application provides optimal user experience across different device states and screen configurations.

5. Implement Dynamic UI Updates

Update your UI based on the detected foldable state:

class MainActivity : AppCompatActivity() {
    private lateinit var foldableStateDetector: FoldableStateDetector
    private lateinit var statusText: TextView
    private lateinit var contentArea: FrameLayout
    
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        
        foldableStateDetector = FoldableStateDetector()
        statusText = findViewById(R.id.status_text)
        contentArea = findViewById(R.id.content_area)
        
        updateUIBasedOnState()
        
        // Observe window state changes
        val windowMetricsCalculator = WindowMetricsCalculator.getOrCreate()
        windowMetricsCalculator.addWindowMetricsListener(this) { windowMetrics ->
            updateUIBasedOnState()
        }
    }
    
    private fun updateUIBasedOnState() {
        val state = foldableStateDetector.detectFoldableState(this)
        statusText.text = "Device State: $state"
        
        // Update content based on state
        when (state) {
            "Folded" -> {
                // Single pane layout
                contentArea.removeAllViews()
                contentArea.addView(createSinglePaneView())
            }
            "Half Folded" -> {
                // Dual pane layout
                contentArea.removeAllViews()
                contentArea.addView(createDualPaneView())
            }
            "Fully Open" -> {
                // Multi-pane layout
                contentArea.removeAllViews()
                contentArea.addView(createMultiPaneView())
            }
        }
    }
}

Why this step: Dynamic UI updates ensure that your application's interface adapts seamlessly to the physical state of the device, providing an optimal user experience.

6. Test Your Implementation

Run your application on a Samsung foldable device or use the Android Emulator with foldable device configurations:

• Use the emulator's device state controls to simulate folding and unfolding
• Test different screen states and orientations
• Verify that UI elements resize and reposition correctly

Why this step: Thorough testing ensures that your application behaves correctly across all foldable device states and provides a consistent user experience.

Summary

This tutorial demonstrated how to build responsive applications for Samsung's foldable devices by implementing foldable state detection and dynamic UI updates. We covered setting up the development environment, detecting device states, and creating layouts that adapt to different screen configurations. By following these steps, developers can create applications that take full advantage of Samsung's foldable device capabilities, providing users with an optimized experience across all device states.

Remember to test your implementation thoroughly on actual foldable devices to ensure proper behavior. The key to successful foldable development is understanding how different screen states affect user experience and adapting your application accordingly.