Identify handheld iOS device families

README.md

@@ -14,6 +14,16 @@ It includes bindings for SDL3, OpenAL, Clipboard and OpenGL ES via ANGLE on Meta
 - `:angle-ios`: native build of Google ANGLE for iOS
 - `:libjglios-gradle-plugin`: `org.ngengine.libjglios`, a Gradle plugin to build iOS apps
 
+## Device classification
+
+`LibJGLIOSDeviceBridge.isMobileDevice()` identifies phone and iPad device families
+through UIKit. It returns false for other interface idioms and for iOS apps
+running on Mac. The native call marshals UIKit access to the main thread, so a
+caller on another thread requires the application's main run loop to be running.
+This describes the device family, not whether a gamepad is connected.
+
+Consumers need matching Java and native core artifacts containing this method.
+
 ## Usage
 
 Consumer projects apply:

core-ios/src/main/java/org/ngengine/libjglios/core/LibJGLIOSDeviceBridge.java

@@ -4,6 +4,9 @@ public final class LibJGLIOSDeviceBridge {
     private LibJGLIOSDeviceBridge() {
     }
 
+    /** Returns true for the phone and tablet device families, not TV or Mac. */
+    public static native boolean isMobileDevice();
+
     public static native boolean isRumbleSupported();
 
     public static native void rumble(float amountHigh, float amountLow, float duration);

core-ios/src/main/native/libjglios_ios_launcher_jni.mm

@@ -294,6 +294,25 @@ void libjglios_show_error_alert(const char* title, const char* message) {
     return JNI_TRUE;
 }
 
+extern "C" JNIEXPORT jboolean JNICALL
+Java_org_ngengine_libjglios_core_LibJGLIOSDeviceBridge_isMobileDevice(JNIEnv*, jclass) {
+    __block bool mobile = false;
+    void (^classify)(void) = ^{
+        UIUserInterfaceIdiom idiom = UIDevice.currentDevice.userInterfaceIdiom;
+        mobile = idiom == UIUserInterfaceIdiomPhone || idiom == UIUserInterfaceIdiomPad;
+        if (@available(iOS 14.0, *)) {
+            // iPhone/iPad apps running on Apple Silicon Macs can retain their original idiom.
+            mobile = mobile && !NSProcessInfo.processInfo.iOSAppOnMac;
+        }
+    };
+    if ([NSThread isMainThread]) {
+        classify();
+    } else {
+        dispatch_sync(dispatch_get_main_queue(), classify);
+    }
+    return mobile ? JNI_TRUE : JNI_FALSE;
+}
+
 extern "C" JNIEXPORT jboolean JNICALL
 Java_org_ngengine_libjglios_core_LibJGLIOSDeviceBridge_isRumbleSupported(JNIEnv*, jclass) {
     return libjglios_device_rumble_supported() ? JNI_TRUE : JNI_FALSE;

core-ios/src/test/java/org/ngengine/libjglios/core/LibJGLIOSDeviceBridgeTest.java

@@ -0,0 +1,18 @@
+package org.ngengine.libjglios.core;
+
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class LibJGLIOSDeviceBridgeTest {
+    @Test
+    void exposesNativeMobileClassification() throws Exception {
+        Method method = LibJGLIOSDeviceBridge.class.getDeclaredMethod("isMobileDevice");
+        assertEquals(boolean.class, method.getReturnType());
+        assertTrue(Modifier.isPublic(method.getModifiers()));
+        assertTrue(Modifier.isStatic(method.getModifiers()));
+        assertTrue(Modifier.isNative(method.getModifiers()));
+    }
+}