QLineEdit: Add an inputRejected() signal for when a key is not allowed

[ChangeLog][QtWidgets][QLineEdit] Added inputRejected() signal for when
a key press is not accepted by the QLineEdit. For instance, when an
invalid key is pressed for a validator set.

Task-number: QTBUG-57448
Change-Id: I39182a78b07b37c6da01905b8da4c57930e3454b
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

5 files changed, 21 insertions, 0 deletions

diff --git a/src/widgets/widgets/qlineedit.cpp b/src/widgets/widgets/qlineedit.cpp
index 9e70b54601..43aa10bdb6 100644
--- a/src/widgets/widgets/qlineedit.cpp
+++ b/src/widgets/widgets/qlineedit.cpp
@@ -1674,6 +1674,16 @@ void QLineEdit::mouseDoubleClickEvent(QMouseEvent* e)
 */
 
 /*!
+    \fn void QLineEdit::inputRejected()
+
+    This signal is emitted when the user presses a key that is not
+    considered to be acceptable input. For example, if a key press
+    results in a validator's validate() call to return Invalid.
+    Another case is when trying to enter in more characters beyond the
+    maximum length of the line edit.
+*/
+
+/*!
     Converts the given key press \a event into a line edit action.
 
     If Return or Enter is pressed and the current text is valid (or
diff --git a/src/widgets/widgets/qlineedit.h b/src/widgets/widgets/qlineedit.h
index 099bf4bb18..b3be97e9b7 100644
--- a/src/widgets/widgets/qlineedit.h
+++ b/src/widgets/widgets/qlineedit.h
@@ -207,6 +207,7 @@ Q_SIGNALS:
     void returnPressed();
     void editingFinished();
     void selectionChanged();
+    void inputRejected();
 
 protected:
     void mousePressEvent(QMouseEvent *) override;
diff --git a/src/widgets/widgets/qlineedit_p.cpp b/src/widgets/widgets/qlineedit_p.cpp
index acf49cda72..bfb92468be 100644
--- a/src/widgets/widgets/qlineedit_p.cpp
+++ b/src/widgets/widgets/qlineedit_p.cpp
@@ -214,6 +214,7 @@ void QLineEditPrivate::init(const QString& txt)
 
     QObject::connect(control, SIGNAL(updateNeeded(QRect)),
             q, SLOT(_q_updateNeeded(QRect)));
+    QObject::connect(control, SIGNAL(inputRejected()), q, SIGNAL(inputRejected()));
 
     QStyleOptionFrame opt;
     q->initStyleOption(&opt);
diff --git a/src/widgets/widgets/qwidgetlinecontrol.cpp b/src/widgets/widgets/qwidgetlinecontrol.cpp
index ff00e26683..670735df3b 100644
--- a/src/widgets/widgets/qwidgetlinecontrol.cpp
+++ b/src/widgets/widgets/qwidgetlinecontrol.cpp
@@ -715,6 +715,8 @@ bool QWidgetLineControl::finishChange(int validateFromState, bool update, bool e
                     return true;
                 }
                 m_cursor = cursorCopy;
+            } else {
+                emit inputRejected();
             }
         }
 #endif
@@ -762,6 +764,8 @@ void QWidgetLineControl::internalSetText(const QString &txt, int pos, bool edite
     if (m_maskData) {
         m_text = maskString(0, txt, true);
         m_text += clearString(m_text.length(), m_maxLength - m_text.length());
+        if (edited && oldText == m_text)
+            emit inputRejected();
     } else {
         m_text = txt.isEmpty() ? txt : txt.left(m_maxLength);
     }
@@ -839,6 +843,8 @@ void QWidgetLineControl::internalInsert(const QString &s)
         addCommand(Command(SetSelection, m_cursor, 0, m_selstart, m_selend));
     if (m_maskData) {
         QString ms = maskString(m_cursor, s);
+        if (ms.isEmpty() && !s.isEmpty())
+            emit inputRejected();
 #ifndef QT_NO_ACCESSIBILITY
         QAccessibleTextInsertEvent insertEvent(accessibleObject(), m_cursor, ms);
         QAccessible::updateAccessibility(&insertEvent);
@@ -866,6 +872,8 @@ void QWidgetLineControl::internalInsert(const QString &s)
             for (int i = 0; i < (int) s.left(remaining).length(); ++i)
                addCommand(Command(Insert, m_cursor++, s.at(i), -1, -1));
             m_textDirty = true;
+        } else {
+            emit inputRejected();
         }
     }
 }
diff --git a/src/widgets/widgets/qwidgetlinecontrol_p.h b/src/widgets/widgets/qwidgetlinecontrol_p.h
index ca70e2c02f..3e33bc0605 100644
--- a/src/widgets/widgets/qwidgetlinecontrol_p.h
+++ b/src/widgets/widgets/qwidgetlinecontrol_p.h
@@ -545,6 +545,7 @@ Q_SIGNALS:
     void accepted();
     void editingFinished();
     void updateNeeded(const QRect &);
+    void inputRejected();
 
 #ifdef QT_KEYPAD_NAVIGATION
     void editFocusChange(bool);