event-handling

问题 I have the following circle and I can play animation on it: Suppose I want to add another shape, such as a rectangle. How I can select between the shapes (circle/rectangle) through a mouse-click to do the animation on the shape being selected. Could someone please give me some guidelines/examples as to how I would go about this. Thank you! Program Code: import javafx.animation.PathTransition; import javafx.application.Application; import static javafx.application.Application.launch; import

问题 Here is a "hello world" button that display a window and button. I would like to do a cout or any other custom functionality when the button is clicked but I'm stuck. #include <QApplication> #include <QPushButton> #include <iostream> int main(int argc, char **argv){ // create app QApplication app (argc, argv); // create window QWidget window; window.setWindowTitle("MyWindow"); window.setFixedSize(600, 480); // create button QPushButton *button = new QPushButton(&window); button->setGeometry

问题 I have a global variable g_user as string and a Label lb_welcome to show username, How can i create a global event when g_user changed then will trigger a function Private Sub Login() g_user = VerifyUser(id,password) lb_welcome.Text = $"Welcome {g_user}" End Sub I try to do something like this:- Private Sub RefreshLabel() lb_welcome.Text = $"Welcome {g_user}" End Sub Private Sub g_user_Changed(sender As Object, e As EventArgs) Handles g_user.Changed RefreshLabel() End Sub Above is just an

问题 I have a global variable g_user as string and a Label lb_welcome to show username, How can i create a global event when g_user changed then will trigger a function Private Sub Login() g_user = VerifyUser(id,password) lb_welcome.Text = $"Welcome {g_user}" End Sub I try to do something like this:- Private Sub RefreshLabel() lb_welcome.Text = $"Welcome {g_user}" End Sub Private Sub g_user_Changed(sender As Object, e As EventArgs) Handles g_user.Changed RefreshLabel() End Sub Above is just an

问题 I need some help. I am new to Events and handlers and I would like to begin using events for decoupling purposes but I am confused. I have a class where I have a list view that is populated on OnAppearing. However to prevent onAppearing to happen each time the page is clicked I load the list once and then I would like to have items to get added or deleted to the list upon being added or removed from the server through the use of events. The ListView page is a list of my favorite newspaper

问题 I have read in several posts here on Stack Overflow that "An event-driven environment like turtle should never have while True: as it potentially blocks out events (e.g. keyboard)." Here is a Python Turtle program that seems to work fine, but which uses the while True: construct. Could someone please explain why this approach is wrong, what problems is creates and what the correct way is to achieve the same result? import turtle import time def move_snake(): """ This function updates the

问题 I have read in several posts here on Stack Overflow that "An event-driven environment like turtle should never have while True: as it potentially blocks out events (e.g. keyboard)." Here is a Python Turtle program that seems to work fine, but which uses the while True: construct. Could someone please explain why this approach is wrong, what problems is creates and what the correct way is to achieve the same result? import turtle import time def move_snake(): """ This function updates the

问题 So I have a SQLAlchemy model that has an event listener: class User(db.Model): id = db.Column(db.Integer, primary_key=True) @event.listens_for(User, "after_insert") @event.listens_for(User, "after_update") def do_something(mapper, connection, self): foo = SomeClass(self) foo.do_something_to_database() And I have a unit test that needs to update/insert the Model @patch('my_package.user.do_something') def test_user(mock_do_something): user = User() # This insert will invoke 'do_something' via

问题 How do I simulate the touch event in React native? Basically I have X and Y cordinates of an onPress event and want to trigger a touch event at the same position again. This is doable in javascript document.elementFromPoint(x, y).click(); But doable in RN? 来源： https://stackoverflow.com/questions/60994249/react-native-trigger-simulate-touch-event

问题 So I have a SQLAlchemy model that has an event listener: class User(db.Model): id = db.Column(db.Integer, primary_key=True) @event.listens_for(User, "after_insert") @event.listens_for(User, "after_update") def do_something(mapper, connection, self): foo = SomeClass(self) foo.do_something_to_database() And I have a unit test that needs to update/insert the Model @patch('my_package.user.do_something') def test_user(mock_do_something): user = User() # This insert will invoke 'do_something' via