Android: docs, app landing page

src/Logic/Web/AndroidPolyfill.ts

@@ -14,10 +14,12 @@ const DatabridgePluginSingleton = registerPlugin<DatabridgePlugin>("Databridge",
     web: () => {
         return <DatabridgePlugin>{
             async request(options: { key: string }): Promise<{ value: string | object }> {
-                return { value: "web" }
-            },
+                if (options.key === "meta") {
+                    return { value: "web" }
+                }
+            }
         }
-    },
+    }
 })
 
 export class AndroidPolyfill {
@@ -32,7 +34,6 @@ export class AndroidPolyfill {
      * @private
      */
     private backfillGeolocation(databridgePlugin: DatabridgePlugin) {
-        const origQueryFunc = navigator?.permissions?.query
         const src = UIEventSource.FromPromise(databridgePlugin.request({ key: "location:request-permission" }))
         src.addCallbackAndRunD(permission => {
             AndroidPolyfill._geolocationPermission.set(<"granted" | "denied">permission.value)
@@ -57,5 +58,23 @@ export class AndroidPolyfill {
         console.log("AndroidPolyfill: received oauth_token; trying to pass them to the oauth lib",token)
         return token
     }
+
+    public static onBackButton(callback: () => boolean, options: {
+        returnToIndex: Store<boolean>
+    }) {
+        console.log("Registering back button callback", callback)
+        DatabridgePluginSingleton.request({ key: "backbutton" }).then(ev => {
+            console.log("AndroidPolyfill: received backbutton: ", ev)
+            if (callback()) {
+                return
+            }
+            // Nothing more to close - we return (if not a single theme) to the index
+            if (options.returnToIndex) {
+                console.log("Back to the index!")
+                window.location.href = "/"
+            }
+        })
+
+    }
 }
 

src/Logic/Web/ThemeViewStateHashActor.ts

@@ -1,6 +1,7 @@
 import ThemeViewState from "../../Models/ThemeViewState"
 import Hash from "./Hash"
 import { MenuState } from "../../Models/MenuState"
+import { AndroidPolyfill } from "./AndroidPolyfill"
 
 export default class ThemeViewStateHashActor {
     private readonly _state: ThemeViewState
@@ -22,7 +23,7 @@ export default class ThemeViewStateHashActor {
     /**
      * Converts the hash to the appropriate theme-view state and, vice versa, sets the hash.
      *
-     * As the navigator-back-button changes the hash first, this class thus also handles the 'back'-button events.
+     * As the navigator-back-button changes the hash first, this class thus also handles the (browser) 'back'-button events.
      *
      * Note that there is no "real" way to intercept the back button, we can only detect the removal of the hash.
      * As such, we use a change in the hash to close the appropriate windows
@@ -30,6 +31,9 @@ export default class ThemeViewStateHashActor {
      */
     constructor(state: ThemeViewState) {
         this._state = state
+        AndroidPolyfill.onBackButton(() => this.back(), {
+            returnToIndex: state.featureSwitches.featureSwitchBackToThemeOverview
+        })
 
         const hashOnLoad = Hash.hash.data
         const containsMenu = this.loadStateFromHash(hashOnLoad)
@@ -66,6 +70,7 @@ export default class ThemeViewStateHashActor {
 
         // When all is done, set the hash. This must happen last to give the code above correct info
         this.setHash()
+
     }
 
     /**
@@ -137,15 +142,26 @@ export default class ThemeViewStateHashActor {
         }
     }
 
+    /**
+     * Returns 'true' if an action was taken
+     * @private
+     */
     private back() {
+        console.log("Received back!")
         const state = this._state
         if (state.previewedImage.data) {
             state.previewedImage.setData(undefined)
-            return
+            return true
         }
         if (state.guistate.closeAll()) {
-            return
+            return true
         }
-        state.selectedElement.setData(undefined)
+        if (state.selectedElement.data) {
+            state.selectedElement.setData(undefined)
+            return true
+        }
+        return false
+
+
     }
 }