actionevent

问题 I am learning Java and would really like to have a deeper understanding of what the ActionEvent e perameter means and stands for. When I code I don't just want to spit out lines that work, but I don't understand. I want to have a full understanding of concepts before I use them. So what specifically is it asking for and what do the two parts(ActionEvent and e) mean? class ButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent e){ } } Thanks. 回答1:

问题 I am learning Java and would really like to have a deeper understanding of what the ActionEvent e perameter means and stands for. When I code I don't just want to spit out lines that work, but I don't understand. I want to have a full understanding of concepts before I use them. So what specifically is it asking for and what do the two parts(ActionEvent and e) mean? class ButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent e){ } } Thanks. 回答1:

问题 I am learning Java and would really like to have a deeper understanding of what the ActionEvent e perameter means and stands for. When I code I don't just want to spit out lines that work, but I don't understand. I want to have a full understanding of concepts before I use them. So what specifically is it asking for and what do the two parts(ActionEvent and e) mean? class ButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent e){ } } Thanks. 回答1:

问题 I am learning Java and would really like to have a deeper understanding of what the ActionEvent e perameter means and stands for. When I code I don't just want to spit out lines that work, but I don't understand. I want to have a full understanding of concepts before I use them. So what specifically is it asking for and what do the two parts(ActionEvent and e) mean? class ButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent e){ } } Thanks. 回答1:

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 21 days ago . I am currently in my first year of Java and have stumbled upon this code on the internet about a battleship game. What I would like to do is understand this code in more simple code. The part that confuses me is the first line: "computerGameBoard = new GameBoard(true, event ->". I

问题 Here is my code, I want to detect when my finger goes down the screen so when I touch the screen I detect the ACTION_DOWN but when I go down the screen with my finger, ACTION_MOVE is not recognized, neither ACTION_UP Do you know why? float x=0; protected void onCreate(Bundle savedInstanceState) { do things ImageView image2 = (ImageView) findViewById(R.id.imageView3); image2.setOnTouchListener(new OnTouchListener(){ @Override public boolean onTouch(View arg0, MotionEvent arg1) { if (arg1

问题 So I have a button that is supposed to add a new user (whose name is taken from another class) to a list after being pressed. When I press the button by manually clicking on it after building and running, it works fine. The thing is that when I call the ActionEvent method through another method, it outputs my System.out.println text but doesnt add any new entries to the list. Any suggestions? Here's the code that is called in a button press (the line marked by an "<--" is the one that only

问题 The following code is a snippet of a program I am getting a nullpointer exception from. When I press the "Add" button on the GUI, an error message pointing to this line: buttonPanel.addButton.setEnabled(false); is displayed. I'm guessing that the addButton is null for some reason although I instantiated it in the constructor of buttonPanel: addButton = new JButton("Add"); addButton.addActionListener(buttonListener); Why is the null pointer error Exception in thread "AWT-EventQueue-0" java

问题 I have this set up to update pretty constantly on the timer, but I want to be able to pause the timer with the spacebar. I have attempted to implement an actionListener, but I am not sure what to apply it to. Most of the examples I can find relate to buttons or text boxes, not keyboard presses inside a jpanel. I have printed src to the console and it doesn't appear to be registering my spacebar as an event... I have tried adding the actionListener, but I am not getting something about the

问题 I'm learning how to use javafx, along with scenebuilder by creating a very basic calculator but I've come across a problem where it's hard for me to find a way to not have a seperate function for each button. I need to know if there's a way for a button to change a variable or give arguments to the action event method that the button is linked to so I don't need seperate methods for each button to call another function. This is an example of what I'm working with. @FXML private Button one;