Add basic support for opening files via Android Intents

This works for file URLs, but this doesn't resolve content URLs yet that
e.g. the default file manager seems to use for standard locations.

src/app/main.cpp

@@ -27,6 +27,11 @@
 #include <QQmlApplicationEngine>
 #include <QQmlContext>
 
+#ifdef Q_OS_ANDROID
+#include <QtAndroid>
+#include <QAndroidJniObject>
+#endif
+
 #include <QCommandLineParser>
 #include <QGuiApplication>
 #include <QIcon>
@@ -69,5 +74,20 @@ int main(int argc, char **argv)
     for (const auto &file : parser.positionalArguments())
         passMgr.importPass(QUrl::fromLocalFile(file));
 
+#ifdef Q_OS_ANDROID
+    // handle opened files
+    const auto activity = QtAndroid::androidActivity();
+    if (activity.isValid()) {
+        const auto intent = activity.callObjectMethod("getIntent", "()Landroid/content/Intent;");
+        if (intent.isValid()) {
+            const auto data = intent.callObjectMethod("getDataString", "()Ljava/lang/String;");
+            if (data.isValid()) {
+                // TODO handle content:// urls
+                passMgr.importPass(QUrl(data.toString()));
+            }
+        }
+    }
+#endif
+
     return app.exec();
 }