在QTapAndHoldGesture之后如何忽略QTapGesture
在QTapAndHoldGesture之后如何忽略QTapGesture
提问于 2018-05-22 06:10:35
我想在我的小部件中加入QTapAndHoldGesture和QTapGesture，并对这些手势做不同的反应。所以我覆盖了QWidget::event方法并添加了这样的代码：
bool event(QEvent *event) override {
if (event->type() == QEvent::Gesture) {
auto g_event = static_cast<QGestureEvent *>(event);
qDebug() << "GestureEvent BEGIN: gestures " << g_event->gestures().size() << ", active: " << g_event->activeGestures();
if (auto g = qobject_cast<QTapGesture *>(g_event->gesture(Qt::TapGesture))) {
g_event->accept(g);
return true;
}
if (auto g = qobject_cast<QTapAndHoldGesture *>(g_event->gesture(Qt::TapAndHoldGesture))) {
if (g->state() == Qt::GestureFinished) {
qDebug("FINISHED!!!");
g->setGestureCancelPolicy(QGesture::CancelAllInContext);
}
g_event->accept(g);
return true;
}问题是我在QTapAndHoldGesture的末尾得到了不想要的QTapGesture。
它看起来是这样的：
GestureEvent BEGIN: gestures 1 , active: (QTapGesture(state=GestureStarted,hotSpot=773.396,492.884,position=773.396,492.884))
GestureEvent BEGIN: gestures 1 , active: (QTapGesture(state=GestureUpdated,hotSpot=773.396,492.884,position=773.396,492.884))
mouse event x 773 , y 493
GestureEvent BEGIN: gestures 1 , active: (QTapGesture(state=GestureUpdated,hotSpot=773.396,492.884,position=773.396,492.884))
...
GestureEvent BEGIN: gestures 1 , active: (QTapGesture(state=GestureUpdated,hotSpot=773.396,492.884,position=773.396,492.884))
GestureEvent BEGIN: gestures 1 , active: (QTapAndHoldGesture(state=GestureStarted,hotSpot=773,493,position=773,493,timeout=700))
GestureEvent BEGIN: gestures 1 , active: (QTapAndHoldGesture(state=GestureFinished,hotSpot=773,493,position=773,493,timeout=700))
FINISHED!!!
GestureEvent BEGIN: gestures 1 , active: (QTapGesture(state=GestureUpdated,hotSpot=773.396,492.884,position=773.396,492.884))
GestureEvent BEGIN: gestures 1 , active: (QTapGesture(state=GestureUpdated,hotSpot=773.396,492.884,position=773.396,492.884))
GestureEvent BEGIN: gestures 1 , active: (QTapGesture(state=GestureFinished,hotSpot=773.396,492.884,position=773.396,492.884))正如您在开始时看到的，我让QTapGesture处于已启动状态，然后是QTapGesture处于已更新状态，在该QTapAndHoldGesture之后和在该QTabGesture完成之后。
我需要一些方法来忽略它。但是我不明白如果不重新实现手势框架:收集事件的位置和时间，并根据这些信息过滤事件。因为我一个接一个的接收手势，不能连接QTapGesture和QTapAndHoldGesture。
那么，在不收集有关QTapGesture的位置和时间的信息的情况下，是否可以在QTapAndHoldGesture之后忽略QGestureEvent
回答 1
Stack Overflow用户
发布于 2018-05-25 21:52:53
因为QTapAndHoldGesture手势也需要“点击”，所以预计它会同时收到这两个：
首先，当用户保持一定时间时(然后，当用户释放
- QTapAndHoldGesture
时，结束触摸
因为它们总是按该顺序接收，所以您可以使用这一事实来过滤或取消将在验证接收QTapAndHoldGesture (即完成)时启动但不会完成的QTapGesture。
如果您正在管理单个触摸点，则不需要时间或位置信息(免责声明:以下内容未经测试)。
bool MyClass::event(QEvent *event) override
{
// QPointer in case we receive partial events. Should remove "isNull()" keys at some point.
static QMap<QPointer<QTapGesture*>, bool> tapGestures;
if (event->type() != QEvent::Gesture)
return QQuickItem::event(event);
auto g_event = static_cast<QGestureEvent *>(event);
if (auto g = qobject_cast<QTapGesture *>(g_event->gesture(Qt::TapGesture))) {
// A TapAndHold was triggered during that tap... let's ignore it
if (tapGestures.value(g))
g_event->ignore(g); // Or handle as you like
if (g->state() == Qt::GestureFinished || g->state() == Qt::GestureCancelled)
tapGestures.remove(g);
else if (!tapGestures.contains(g))
tapGestures.insert(g, false);
g_event->accept(g);
return true;
}
if (auto g = qobject_cast<QTapAndHoldGesture *>(g_event->gesture(Qt::TapAndHoldGesture))) {
// Probably not needed if the gesture handle doesn't conflict with another component
//if (g->state() == Qt::GestureFinished)
// g->setGestureCancelPolicy(QGesture::CancelAllInContext);
// Mark all QTapGesture in progress to be ignored
for (auto it = tapGestures.begin(); it != tapGestures.end(); ++it)
it.value() = true;
g_event->accept(g);
return true;
}
}所有手势在QGestureManager class中都可用，因此可能有一种方法可以访问它。
还有GestureOverride事件类型，但我相信在您的情况下它不会被触发。
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原文链接：
https://stackoverflow.com/questions/50457215
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