[libcamera-devel] [PATCH 2/4] qcam: Support Hotplug for Camera Selection Dialog

[Utkarsh Tiwari]

Currently if there is HotPlug event when the user is on the Camera
selection dialog, the QComboBox didn't update to reflect the change.

If the cameraIdComboBox_ contains a valid QComboBox then update it to
reflect the HotPlug change. Check the validity of QComboBox pointer by
guarding it with a QPointer.

Signed-off-by: Utkarsh Tiwari <utkarsh02t at gmail.com>
---
 src/qcam/main_window.cpp | 23 +++++++++++++++--------
 src/qcam/main_window.h   |  4 ++++
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
index 7761a6c6..80a73b68 100644
--- a/src/qcam/main_window.cpp
+++ b/src/qcam/main_window.cpp
@@ -293,18 +293,15 @@ void MainWindow::switchCamera(int index)
 
 std::string MainWindow::chooseCamera()
 {
-	QStringList cameras;
 	std::string result;
 
 	/* Present a dialog box to pick a camera. */
 	QDialog *cameraSelectDialog = new QDialog(this);
 
 	/* Setup a QComboBox to display camera Ids. */
+	cameraIdComboBox_ = new QComboBox;
 	for (const std::shared_ptr<Camera> &cam : cm_->cameras())
-		cameras.push_back(QString::fromStdString(cam->id()));
-
-	QComboBox *cameraIdComboBox = new QComboBox;
-	cameraIdComboBox->addItems(cameras);
+		cameraIdComboBox_->addItem(QString::fromStdString(cam->id()));
 
 	/* Setup QDialogButtonBox. */
 	QDialogButtonBox *dialogButtonBox = new QDialogButtonBox;
@@ -313,7 +310,7 @@ std::string MainWindow::chooseCamera()
 
 	connect(dialogButtonBox, &QDialogButtonBox::accepted,
 		this, [&]() {
-			result = cameraIdComboBox->currentText().toStdString();
+			result = cameraIdComboBox_->currentText().toStdString();
 			cameraSelectDialog->accept();
 		});
 
@@ -325,7 +322,7 @@ std::string MainWindow::chooseCamera()
 
 	/* Setup the layout for the dialog. */
 	QFormLayout *cameraSelectLayout = new QFormLayout(cameraSelectDialog);
-	cameraSelectLayout->addRow("Camera: ", cameraIdComboBox);
+	cameraSelectLayout->addRow("Camera: ", cameraIdComboBox_);
 	cameraSelectLayout->addWidget(dialogButtonBox);
 
 	cameraSelectDialog->exec();
@@ -628,7 +625,12 @@ void MainWindow::processHotplug(HotplugEvent *e)
 	HotplugEvent::PlugEvent event = e->hotplugEvent();
 
 	if (event == HotplugEvent::HotPlug) {
-		cameraCombo_->addItem(QString::fromStdString(camera->id()));
+		QString cameraId = QString::fromStdString(camera->id());
+		cameraCombo_->addItem(cameraId);
+
+		/* Update cameraIdCombox_ to include the new camera. */
+		if (cameraIdComboBox_)
+			cameraIdComboBox_->addItem(cameraId);
 	} else if (event == HotplugEvent::HotUnplug) {
 		/* Check if the currently-streaming camera is removed. */
 		if (camera == camera_.get()) {
@@ -638,6 +640,11 @@ void MainWindow::processHotplug(HotplugEvent *e)
 			cameraCombo_->setCurrentIndex(0);
 		}
 
+		if (cameraIdComboBox_) {
+			int cameraIdIndex = cameraIdComboBox_->findText(QString::fromStdString(camera_->id()));
+			cameraIdComboBox_->removeItem(cameraIdIndex);
+		}
+
 		int camIndex = cameraCombo_->findText(QString::fromStdString(camera->id()));
 		cameraCombo_->removeItem(camIndex);
 	}
diff --git a/src/qcam/main_window.h b/src/qcam/main_window.h
index fc70920f..b8122eb9 100644
--- a/src/qcam/main_window.h
+++ b/src/qcam/main_window.h
@@ -23,7 +23,9 @@
 #include <QMainWindow>
 #include <QMutex>
 #include <QObject>
+#include <QPointer>
 #include <QQueue>
+#include <QStringList>
 #include <QTimer>
 
 #include "../cam/stream_options.h"
@@ -99,6 +101,8 @@ private:
 	QString title_;
 	QTimer titleTimer_;
 
+	QPointer<QComboBox> cameraIdComboBox_;
+
 	/* Options */
 	const OptionsParser::Options &options_;
 
-- 
2.25.1