texteditor example: check if document is null before using it

This hasn't been an issue so far probably because those properties were
accessed after m_doc had been set. However, adding some debug text can
trigger a crash:

    Text {
        text: "document.cursorPosition=" + document.cursorPosition
    }

Change-Id: Ib468815cdc0b103a2384457ab937cc3b764b96c8
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

1 files changed, 6 insertions, 0 deletions

diff --git a/examples/quickcontrols/controls/texteditor/src/documenthandler.cpp b/examples/quickcontrols/controls/texteditor/src/documenthandler.cpp
index 2e03f747..b07099e2 100644
--- a/examples/quickcontrols/controls/texteditor/src/documenthandler.cpp
+++ b/examples/quickcontrols/controls/texteditor/src/documenthandler.cpp
@@ -169,6 +169,9 @@ void DocumentHandler::reset()
 
 QTextCursor DocumentHandler::textCursor() const
 {
+    if (!m_doc)
+        return QTextCursor();
+
     QTextCursor cursor = QTextCursor(m_doc);
     if (m_selectionStart != m_selectionEnd) {
         cursor.setPosition(m_selectionStart);
@@ -199,6 +202,9 @@ void DocumentHandler::setSelectionEnd(int position)
 
 void DocumentHandler::setAlignment(Qt::Alignment a)
 {
+    if (!m_doc)
+        return;
+
     QTextBlockFormat fmt;
     fmt.setAlignment((Qt::Alignment) a);
     QTextCursor cursor = QTextCursor(m_doc);