Add a function that minimizes the Android app (#692)

Add a function that minimizes the Android app

client/android/src/org/amnezia/vpn/AmneziaActivity.kt

@@ -476,4 +476,12 @@ class AmneziaActivity : QtActivity() {
             window.setFlags(flag, LayoutParams.FLAG_SECURE)
         }
     }
+
+    @Suppress("unused")
+    fun minimizeApp() {
+        Log.v(TAG, "Minimize application")
+        mainScope.launch {
+            moveTaskToBack(false)
+        }
+    }
 }

client/platforms/android/android_controller.cpp

@@ -209,6 +209,11 @@ void AndroidController::setScreenshotsEnabled(bool enabled)
     callActivityMethod("setScreenshotsEnabled", "(Z)V", enabled);
 }
 
+void AndroidController::minimizeApp()
+{
+    callActivityMethod("minimizeApp", "()V");
+}
+
 // Moving log processing to the Android side
 jclass AndroidController::log;
 jmethodID AndroidController::logDebug;

client/platforms/android/android_controller.h

@@ -40,6 +40,7 @@ public:
     void exportLogsFile(const QString &fileName);
     void clearLogs();
     void setScreenshotsEnabled(bool enabled);
+    void minimizeApp();
 
     static bool initLogging();
     static void messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &message);

client/ui/controllers/pageController.cpp

@@ -7,6 +7,7 @@
 #endif
 
 #ifdef Q_OS_ANDROID
+    #include "platforms/android/android_controller.h"
     #include "platforms/android/android_utils.h"
     #include <QJniObject>
 #endif
@@ -74,6 +75,13 @@ void PageController::closeWindow()
 #endif
 }
 
+void PageController::hideWindow()
+{
+#ifdef Q_OS_ANDROID
+    AndroidController::instance()->minimizeApp();
+#endif
+}
+
 void PageController::keyPressEvent(Qt::Key key)
 {
     switch (key) {

client/ui/controllers/pageController.h

@@ -76,6 +76,7 @@ public slots:
     QString getPagePath(PageLoader::PageEnum page);
 
     void closeWindow();
+    void hideWindow();
     void keyPressEvent(Qt::Key key);
 
     unsigned int getInitialPageNavigationBarColor();

client/ui/qml/Pages2/PageSetupWizardStart.qml

@@ -24,6 +24,7 @@ PageType {
 
         function onClosePage() {
             if (stackView.depth <= 1) {
+                PageController.hideWindow()
                 return
             }
             stackView.pop()

client/ui/qml/Pages2/PageStart.qml

@@ -40,6 +40,7 @@ PageType {
 
         function onClosePage() {
             if (tabBarStackView.depth <= 1) {
+                PageController.hideWindow()
                 return
             }
             tabBarStackView.pop()