Android: Implement QtLayout backend interface

Small interface, just for QtLayout. This is used in
QtAndroid::qtLayout(), which is called by functions handling the
virtual keyboard and the keyboard handles.

Task-number: QTBUG-118874
Change-Id: Ib9b2830136d05dfd70c9c6ca86ac29be36cc5c30
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>

src/android/jar/CMakeLists.txt

@@ -44,6 +44,7 @@ set(java_sources
     src/org/qtproject/qt/android/QtWindowInterface.java
     src/org/qtproject/qt/android/QtAccessibilityInterface.java
     src/org/qtproject/qt/android/QtMenuInterface.java
+    src/org/qtproject/qt/android/QtLayoutInterface.java
 )
 
 qt_internal_add_jar(Qt${QtBase_VERSION_MAJOR}Android

src/android/jar/src/org/qtproject/qt/android/QtActivityDelegate.java

@@ -32,7 +32,7 @@ import android.widget.PopupMenu;
 import java.util.HashMap;
 
 class QtActivityDelegate extends QtActivityDelegateBase
-        implements QtWindowInterface, QtAccessibilityInterface, QtMenuInterface
+        implements QtWindowInterface, QtAccessibilityInterface, QtMenuInterface, QtLayoutInterface
 {
     private static final String QtTAG = "QtActivityDelegate";
 
@@ -63,6 +63,8 @@ class QtActivityDelegate extends QtActivityDelegateBase
                                             (QtAccessibilityInterface)QtActivityDelegate.this);
             BackendRegister.registerBackend(QtMenuInterface.class,
                                             (QtMenuInterface)QtActivityDelegate.this);
+            BackendRegister.registerBackend(QtLayoutInterface.class,
+                                            (QtLayoutInterface)QtActivityDelegate.this);
         }
     }
 
@@ -73,12 +75,12 @@ class QtActivityDelegate extends QtActivityDelegateBase
             BackendRegister.unregisterBackend(QtWindowInterface.class);
             BackendRegister.unregisterBackend(QtAccessibilityInterface.class);
             BackendRegister.unregisterBackend(QtMenuInterface.class);
+            BackendRegister.unregisterBackend(QtLayoutInterface.class);
         }
     }
 
-    @UsedFromNativeCode
     @Override
-    QtLayout getQtLayout()
+    public QtLayout getQtLayout()
     {
         return m_layout;
     }

src/android/jar/src/org/qtproject/qt/android/QtActivityDelegateBase.java

@@ -45,7 +45,6 @@ abstract class QtActivityDelegateBase
 
     // Subclass must implement these
     abstract void startNativeApplicationImpl(String appParams, String mainLib);
-    abstract QtLayout getQtLayout();
 
     // With these we are okay with default implementation doing nothing
     void setUpLayout() {}

src/android/jar/src/org/qtproject/qt/android/QtEmbeddedDelegate.java

@@ -25,7 +25,7 @@ import java.util.HashMap;
 
 class QtEmbeddedDelegate extends QtActivityDelegateBase
         implements QtNative.AppStateDetailsListener, QtEmbeddedViewInterface, QtWindowInterface,
-                   QtMenuInterface
+                   QtMenuInterface, QtLayoutInterface
 {
     private static final String QtTAG = "QtEmbeddedDelegate";
     // TODO simplistic implementation with one QtView, expand to support multiple views QTBUG-117649
@@ -98,10 +98,12 @@ class QtEmbeddedDelegate extends QtActivityDelegateBase
                 m_backendsRegistered = true;
                 BackendRegister.registerBackend(QtWindowInterface.class, (QtWindowInterface)this);
                 BackendRegister.registerBackend(QtMenuInterface.class, (QtMenuInterface)this);
+                BackendRegister.registerBackend(QtLayoutInterface.class, (QtLayoutInterface)this);
             } else if (!details.isStarted && m_backendsRegistered) {
                 m_backendsRegistered = false;
                 BackendRegister.unregisterBackend(QtWindowInterface.class);
                 BackendRegister.unregisterBackend(QtMenuInterface.class);
+                BackendRegister.unregisterBackend(QtLayoutInterface.class);
             }
         }
     }
@@ -128,9 +130,8 @@ class QtEmbeddedDelegate extends QtActivityDelegateBase
         QtNative.startApplication(appParams, mainLib);
     }
 
-    @UsedFromNativeCode
     @Override
-    QtLayout getQtLayout()
+    public QtLayout getQtLayout()
     {
         // TODO verify if returning m_view here works, this is used by the androidjniinput
         // when e.g. showing a keyboard, so depends on getting the keyboard focus working

src/android/jar/src/org/qtproject/qt/android/QtLayoutInterface.java

@@ -0,0 +1,8 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+package org.qtproject.qt.android;
+
+@UsedFromNativeCode
+interface QtLayoutInterface {
+    QtLayout getQtLayout();
+}

src/plugins/platforms/android/androidjniinput.cpp

@@ -24,6 +24,7 @@ Q_LOGGING_CATEGORY(lcQpaInputMethods, "qt.qpa.input.methods");
 using namespace QtAndroid;
 
 Q_DECLARE_JNI_CLASS(QtLayout, "org/qtproject/qt/android/QtLayout")
+Q_DECLARE_JNI_CLASS(QtLayoutInterface, "org/qtproject/qt/android/QtLayoutInterface")
 
 namespace QtAndroidInput
 {
@@ -98,7 +99,9 @@ namespace QtAndroidInput
 
     QJniObject qtLayout()
     {
-        return qtActivityDelegate().callMethod<QtJniTypes::QtLayout>("getQtLayout");
+        AndroidBackendRegister *reg = QtAndroid::backendRegister();
+        return reg->callInterface<QtJniTypes::QtLayoutInterface, QtJniTypes::QtLayout>(
+                "getQtLayout");
     }
 
     void updateSelection(int selStart, int selEnd, int candidatesStart, int candidatesEnd)