android: Improve changing web theme (#402)

src/android/app/src/main/assets/ui.css

@@ -33,6 +33,37 @@ html.light {
   --band: #f2f5f7;
 }
 
+@property --bg {
+  syntax: "<color>";
+  inherits: true;
+  initial-value: #ffffff;
+}
+@property --text {
+  syntax: "<color>";
+  inherits: true;
+  initial-value: #111111;
+}
+@property --muted {
+  syntax: "<color>";
+  inherits: true;
+  initial-value: #4a555c;
+}
+@property --line {
+  syntax: "<color>";
+  inherits: true;
+  initial-value: rgba(128, 128, 128, 0.2);
+}
+@property --card {
+  syntax: "<color>";
+  inherits: true;
+  initial-value: rgba(128, 128, 128, 0.1);
+}
+@property --band {
+  syntax: "<color>";
+  inherits: true;
+  initial-value: #f2f5f7;
+}
+
 * {
   box-sizing: border-box;
   -webkit-tap-highlight-color: transparent;

src/android/app/src/main/java/org/nxemu/ui/main/MainActivity.kt

@@ -52,6 +52,9 @@ open class MainActivity : ComponentActivity() {
     }
     private val settingChangedForwarder: (String) -> Unit = { setting ->
         runOnUiThread {
+            if (setting == NXUISetting.ThemeMode) {
+                applyWebViewTheme()
+            }
             webView.evaluateJavascript(
                 "onSettingChanged('${setting.replace("'", "\\'")}')",
                 null
@@ -175,6 +178,7 @@ open class MainActivity : ComponentActivity() {
         emulationLaunchPending = false
         InputHandler.updateControllerData()
         inputManager()?.registerInputDeviceListener(inputDeviceListener, null)
+        applyWebViewTheme()
         refreshConnectedControllers()
         resumeRunningGame()
     }
@@ -359,6 +363,12 @@ open class MainActivity : ComponentActivity() {
 
     fun editOverlayLayout() {
         startActivity(Intent(this, OverlayLayoutActivity::class.java))
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
+            overrideActivityTransition(Activity.OVERRIDE_TRANSITION_OPEN, 0, 0)
+        } else {
+            @Suppress("DEPRECATION")
+            overridePendingTransition(0, 0)
+        }
     }
 
     override fun onDestroy() {
@@ -389,6 +399,15 @@ open class MainActivity : ComponentActivity() {
         )
     }
 
+    private fun applyWebViewTheme() {
+        if (!::webView.isInitialized) {
+            return
+        }
+        webView.setBackgroundColor(ThemeHelper.backgroundColor(this))
+        ThemeHelper.applySystemBars(this)
+        webView.evaluateJavascript("typeof applyTheme==='function'&&applyTheme()", null)
+    }
+
     companion object {
         private const val STICK_REPEAT_MS = 220L
         private const val STICK_DEADZONE = 0.5f