Android: Add OnDataChangedListerner callback interface

Adds a new interface to QtAbstractItemModel Java class that
can be used as a callback to listen to the changes of an
editable model. The model can be an implementation of
QtAbstractItemModel with an underlaying C++
QAndroidAbstractModelProxy instance, or it can be an instance
of QtAbstractItemModel that proxies and refers to
a QAbstractItemModel instance.

This also adds setOnDataChangedListener() to QtAbstractItemModel
so that it can call the interface callback function by connecting
dataChanged() signal of the native instance to a lambda that
invokes the handleDataChanged() private method of the JVM instance.

Task-number: QTBUG-129387
Task-number: QTBUG-130251
Task-number: QTBUG-130252
Change-Id: I23da9e980b5402f4dcf7446560155271ccd8809e
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>

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

@@ -263,6 +263,27 @@ public abstract class QtAbstractItemModel
     public void dataChanged(QtModelIndex topLeft, QtModelIndex bottomRight, int[] roles) {
         jni_dataChanged(topLeft, bottomRight, roles);
     }
+    /**
+     * Interface for a callback to be invoked when the data in an existing item changes.
+     */
+    public interface OnDataChangedListener {
+        /**
+         * Called when the data in an existing item changes.
+         *
+         * @param topLeft The top-left index of changed items
+         * @param bottomRight The bottom-right index of changed items
+         * @param roles Changed roles; Empty array indicates all roles
+         */
+        void onDataChanged(QtModelIndex topLeft, QtModelIndex bottomRight, int[] roles);
+    }
+    /**
+     * Register a callback to be invoked when the data in an existing item changes.
+     *
+     * @param listener The data change listener
+     */
+    public void setOnDataChangedListener(OnDataChangedListener listener) {
+        m_OnDataChangedListener = listener;
+    }
     /**
      * Begins a column insertion operation.
 
@@ -503,6 +524,15 @@ public abstract class QtAbstractItemModel
     */
     protected final void endResetModel() { jni_endResetModel(); }
 
+    private void handleDataChanged(QtModelIndex topLeft, QtModelIndex bottomRight, int[] roles)
+    {
+        if (m_OnDataChangedListener != null) {
+            QtNative.runAction(() -> {
+                if (m_OnDataChangedListener != null)
+                    m_OnDataChangedListener.onDataChanged(topLeft, bottomRight, roles);
+            });
+        }
+    }
     private native void jni_beginInsertColumns(QtModelIndex parent, int first, int last);
     private native void jni_beginInsertRows(QtModelIndex parent, int first, int last);
     private native boolean jni_beginMoveColumns(QtModelIndex sourceParent, int sourceFirst,
@@ -529,6 +559,7 @@ public abstract class QtAbstractItemModel
                                         int[] roles);
 
     private long m_nativeReference = 0;
+    private OnDataChangedListener m_OnDataChangedListener;
     private QtAbstractItemModel(long nativeReference) { m_nativeReference = nativeReference; }
     private void detachFromNative() { m_nativeReference = 0; }
 

src/corelib/platform/android/qandroiditemmodelproxy.cpp

@@ -160,6 +160,19 @@ QAndroidItemModelProxy::createNativeProxy(QJniObject itemModel)
             if (proxy)
                 proxy->jInstance.callMethod<void>("detachFromNative");
         });
+
+        connect(nativeProxy, &QAndroidItemModelProxy::dataChanged, nativeProxy,
+                [nativeProxy](const QModelIndex &topLeft, const QModelIndex &bottomRight,
+                              const QList<int> &roles) {
+                    auto proxy = qobject_cast<QAndroidItemModelProxy *>(nativeProxy);
+                    if (proxy) {
+                        QJniObject jInstance = proxy->jInstance;
+                        jInstance.callMethod<void>("handleDataChanged",
+                                                    QAndroidModelIndexProxy::jInstance(topLeft),
+                                                    QAndroidModelIndexProxy::jInstance(bottomRight),
+                                                    QJniArray<jint>(roles));
+                    }
+                });
     }
     return nativeProxy;
 }