The value of the alignment argument must be one of FlowLayout.LEFT, FlowLayout.RIGHT, FlowLayout.CENTER, FlowLayout.LEADING, or FlowLayout.TRAILING. Here is the JPanel method: public void JPanelArray () else if (response = JOptionPane. Constructs a new FlowLayout with the specified alignment and a default 5-unit horizontal and vertical gap. Accessing or modifying a null object’s field. These can be: Invoking a method from a null object. The WrapLayout extends FlowLayout and overrides the preferred size calculation to give the. So the solution is to use a different layout manager. The default preferred size calculation for a FlowLayout assumes a single row of components. NullPointerException is thrown when program attempts to use an object reference that has the null value. Correct, the preferredSize () needs to be dynamically calculated as components are added to the panel. In Java, a special null value can be assigned to an object reference. Exception in thread "AWT-EventQueue-0" Īt TicTacToeFrame.JPanelArray(TicTacToeFrame.java:133)Īt Cell$mouseListener.actionPerformed(Cell.java:89)Īt (Unknown Source)Īt $n(Unknown Source)Īt .dispatch(Unknown Source)Īt (Unknown Source)Īt $500(Unknown Source)Īt $3.run(Unknown Source)Īt (Native Method)Īt $JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)Īt (Unknown Source)Īt (Unknown Source)Īt (Unknown Source)Īt (Unknown Source)Īt (Unknown Source)Īt (Unknown Source) NullPointerException is a RuntimeException. The stack trace shows that the JPanelArray () is the cause of the null pointer exception, specifically line 133 panels. FlowLayout, as a design administrator gives a format that is simple and utilized as default by the JPanel, it makes it each part observed by its preferred size and organizes them in horizontal wrapping lines with the goal that they will have spacing. When running my program I keep getting an Exception in thread "AWT-EventQueue-0" . This is an instructional exercise where we will going to make a program with a FlowLayout as Layout Manager in Java.
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