GUI module example: 2 button dialog (#308)

* GUI: reusable module example

applications/gui/modules/dialog.h

@@ -0,0 +1,69 @@
+#pragma once
+
+#include <gui/view.h>
+
+/* Dialog anonymous structure */
+typedef struct Dialog Dialog;
+
+/* Dialog result */
+typedef enum {
+    DialogResultLeft,
+    DialogResultRight,
+} DialogResult;
+
+/* Dialog result callback type
+ * @warning comes from GUI thread
+ */
+typedef void (*DialogResultCallback)(DialogResult result, void* context);
+
+/* Allocate and initialize dialog
+ * This dialog used to ask simple questions like Yes/
+ */
+Dialog* dialog_alloc();
+
+/* Deinitialize and free dialog
+ * @param dialog - Dialog instance
+ */
+void dialog_free(Dialog* dialog);
+
+/* Get dialog view
+ * @param dialog - Dialog instance
+ * @return View instance that can be used for embedding
+ */
+View* dialog_get_view(Dialog* dialog);
+
+/* Set dialog header text
+ * @param dialog - Dialog instance
+ * @param text - text to be shown
+ */
+void dialog_set_result_callback(Dialog* dialog, DialogResultCallback callback);
+
+/* Set dialog header text
+ * @param dialog - Dialog instance
+ * @param context - context pointer, will be passed to result callback
+ */
+void dialog_set_context(Dialog* dialog, void* context);
+
+/* Set dialog header text
+ * @param dialog - Dialog instance
+ * @param text - text to be shown
+ */
+void dialog_set_header_text(Dialog* dialog, const char* text);
+
+/* Set dialog text
+ * @param dialog - Dialog instance
+ * @param text - text to be shown
+ */
+void dialog_set_text(Dialog* dialog, const char* text);
+
+/* Set left button text
+ * @param dialog - Dialog instance
+ * @param text - text to be shown
+ */
+void dialog_set_left_button_text(Dialog* dialog, const char* text);
+
+/* Set right button text
+ * @param dialog - Dialog instance
+ * @param text - text to be shown
+ */
+void dialog_set_right_button_text(Dialog* dialog, const char* text);