12/20/2023 0 Comments Flowlayout start new lineIf you are not interested in learning all the details of layout management, you might prefer to use the GroupLayout layout manager combined with a builder tool to lay out your GUI. To create more complex frames, you need use other types of LayoutManager classes, elements of type, or, you can use an integrated developing environment (IDE) like Netbeans to visually create the interface.Note: This lesson covers writing layout code by hand, which can be challenging. Import import import import import import import import import public class FrameTest extends JFrame implements ActionListener When the button is pressed, the two text fields will be loaded with the dimensions of the frame and an 'x' character will be appended to the text area: We will write a JFrame that contains two JLabel, two JTextField, one JTextArea and one JButton. More about handlers in the Oracle tutorial. Method getSource() returns a reference of type Object to the component that generated the event. The same handler can be associated to multiple elements, in which case, in order to know which element triggered the event, the method getSource() is used, defined in class which is the superclass for all objects received as arguments by handler methods (, , etc.). public void addMouseListener(MouseListener _listener) - for events related to the mouse.public void addActionListener(ActionListener _listener) - for action type events, meaning activating a component (like click on a button, writing a text in a text field, etc.).Methods that add a handled to a component look like this: These methods are executed in parallel with the main program, as threads, in the moment when the event is triggered. These handlers are, in fact, methods, defined in certain interfaces. For example, then a button is pressed, or when the mouse moves over the component, or when something is typed in a text component, etc. ![]() To each event, an action can be associated which is executed when that event is triggered. More about layouts in the Oracle tutorial.Įvery JComponent supports a list of events which it is sensitive to. This type of layout is useful to generate wizard type applications in which the user skips from one screen to the next and back by using Next and Previous buttons. Only one element can be placed in either of the five positions.ĬardLayout is used to add more components to a container, from which only one is visible at any given time. GridLayout is used to place components in a matrix with configurable size.īorderLayout is used to place elements along the four borders and in center: NORTH, SOUTH, EAST, WEST and CENTER. Some of them are:įlowLayout is used to place elements horizontally, until they don't fit anymore, in which case, subsequent components are placed on the next line. These classes describe how elements are placed in a container. Cele mai importante sunt:Īnother series of classes required for implementing a GUI is the set of classes implementing interface. Aceste clase descriu modul în care elementele se așează într-un Container. ![]() O altă serie de clase necesară pentru implementarea unei interfețe grafice este setul de clase care extind interfața. JTextArea is a component where you can add a large text on more than one line. This too can have an associated event handler of type ActionListener which is triggered when Enter is pressed when the text field is focused. JTextField is an area where a short text can be entered, on a single line. It's used by specifying an event handler of type ActionListener (see #Event Handlers) which is triggered when the button is clicked. This can have either a text or an image displayed on top. JLabel is a component used to display text or image in a container. ![]() This is particularly useful when reusing a panel. It is recommended not to place elements directly in a JFrame, but in a JPanel that is placed in a JFrame. It can be visible, changing the background color, the image model or having a border, or be invisible, only used for the hierarchy of the content. JPanel is a generic container that can hold other elements. For a more detailed description, read the Oracle tutorial. Next, we'll present the elements required for task 6. So, there is a hierarchy of components, each element called parent containing other sub-components called children. This is a JFrame containing the most used elements in Swing:Īll Swing objects, with the exception of class JFrame, inherit class which in turn inherits (indirectly) class. ![]() It's the element associated with the horizontal bar containing the icon, application name and the three buttons minimize, maximize and close: The main container class for GUI elements is. The package that contains the majority of classes for Swing applications is java.swing, some other other classes are used from the older package java.awt.
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