Java gui windows

I'm not sure what was attempted here but it seems that it doesn't work at all. Maybe it was made with an older version of Java and now it's not compatible with newer versions. Nice decompiler, but still lacks some features.

I put it online, so everybody might no-hassle test it: www. Pretty good!. It has been able to decompile in quite an intelligible way the code. Notes: If a component is added directly into a JFrame , it is added into the content-pane of JFrame instead, i. Swing uses the AWT event-handling classes in package java. Swing introduces a few new event-handling classes in package javax. Let's convert the earlier AWT application example into Swing. Compare the two source files and note the changes which are highlighted.

The display is shown below. The JFrams 's method getContentPane returns the content-pane which is a java. Containter of the JFrame. You can then set its layout the default layout is BorderLayout , and add components into it. Instead of writing a WindowEvent listener with a windowClosing handler to process the "close-window" button, JFrame provides a method called setDefaultCloseOperation to sets the default operation when the user initiates a "close" on this frame. Typically, we choose the option JFrame.

In the previous examples, we invoke the constructor directly in the entry main method to setup the GUI components. The constructor will be executed in the so-called "Main-Program" thread. This may cause multi-threading issues such as unresponsive user-interface and deadlock. It is recommended to execute the GUI setup codes in the so-called "Event-Dispatching" thread, instead of "Main-Program" thread, for thread-safe operations. Event-dispatching thread, which processes events, should be used when the codes updates the GUI.

To run the constructor on the event-dispatching thread, invoke static method SwingUtilities. The codes will be run after all pending events have been processed. Note: javax. At times, for example in game programming, the constructor or the main may contains non-GUI codes. This GUI init method shall be run in the event-dispatching thread.

This warning message is triggered because java. Frame via its superclass java. Component implements the java. Serializable interface. This interface enables the object to be written out to an output stream serially via method writeObject ; and read back into the program via method readObject. The serialization runtime uses a number called serialVersionUID to ensure that the object read into the program is compatible with the class definition, and not belonging to another version.

Introduction So far, we have covered the basic programming constructs such as variables, data types, decision, loop, array and method and introduced the important concept of Object-Oriented Programming OOP.

The java. Custom graphics classes, such as Graphics , Color and Font. They are also called widgets , controls in other graphics systems. A container can also hold sub-containers. To write a GUI program, we typically start with a subclass extending from java. Frame to inherit the main window as follows: import java. A Dialog has a title-bar containing an icon, a title and a close button and a content display area, as illustrated.

An AWT Applet in package java. Applet is no longer supported in most of the browsers. Secondary Containers: Panel and ScrollPane Secondary containers are placed inside a top-level container or another secondary container. AWT provides these secondary containers: Panel : a rectangular box used to layout a set of related GUI components in pattern such as grid or flow. Label A java. Note that three static constants Label.

LEFT , Label. CENTER are defined in the class for you to specify the alignment rather than asking you to memorize arbitrary integer values. The second constructor constructs a Label object with the given text string in default of left-aligned. The third constructor constructs a Label object with an initially empty string.

You could set the label text via the setText method later. LEFT, Label. Constructing a Component and Adding the Component into a Container Three steps are necessary to create and place a GUI component: Declare the component with an identifier name ; Construct the component by invoking an appropriate constructor via the new operator; Identify the container such as Frame or Panel designed to hold this component.

The container can then add this component onto itself via aContainer. Every container has a add Component method. Take note that it is the container that actively and explicitly adds a component onto itself, NOT the other way.

Button A java. Disabled Button cannot be clicked. Event Clicking a button fires a so-called ActionEvent and triggers a certain programmed action. TextField A java. Each time you click the button, the counter's value increases by 1. Dissecting the AWTCounter. In other words, this class AWTCounter is a Frame , and inherits all the attributes and behaviors of a Frame , such as the title bar and content pane. Lines 11 to 47 define a constructor, which is used to setup the GUI components and event handlers.

In Line 13, the setLayout inherited from the superclass Frame is used to set the layout of the container. FlowLayout is used which arranges the components in left-to-right and flows into next row in a top-to-bottom manner. A Label , TextField non-editable , and Button are constructed.

We invoke the add method inherited from the superclass Frame to add these components into container. In Line , we invoke the setSize and the setTitle inherited from the superclass Frame to set the initial size and the title of the Frame. The setVisible true method Line 42 is then invoked to show the display. Line is used to setup the callback event-handler, which will be discussed in length later. In brief, whenever the button is clicked, the actionPerformed will be called.

In the actionPerformed Lines , the counter value increases by 1 and displayed on the TextField. The constructor is executed to initialize the GUI components and setup the event-handlers. The GUI program then waits for the user action. For example, if we insert the following code before and after the setvisible : System. Frame Line 6 - the top-level window container.

In the constructor Line 14 , we constructs 4 components - 2 anonymous java. Label s and 2 java. TextField s. The Frame adds the components, in GridLayout. The listener class needs to implement ActionListener interface and provides implementation to method actionPerformed.

Callback Methods In the above examples, the method actionPerformed is known as a callback method. JavaScript can attach a Callback method to an Event Directly In some languages, you can directly attach a method or function to an event such as mouse-click.

The sequence of steps is illustrated above: The source object registers its listener s for a certain type of event. The source is triggered by a user.

The source create a XxxEvent object, which encapsulates the necessary information about the activation. For example, the x, y position of the mouse pointer, the text entered, etc. Finally, for each of the XxxEvent listeners in the listener list, the source invokes the appropriate handler on the listener s , which provides the programmed response.

The listener s is required to implement ActionListener interface, and override the actionPerformed method to provide the response. In Line , we write an inner class called BtnCountListener , which override the actionPerformed to increment and display the count. An inner class is a class defined inside an outer class, and it can access the private entities of the outer class. We will elaborate on the inner class in the next section. The source object registers listener via the addActionListener.

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Linked 9. Under these conditions, when the user closes a frame, the window listener will be called first. For more information about handling window-closing events, see How to Write Window Listeners. Besides handling window-closing events, window listeners can also react to other window state changes, such as iconification and activation. The following tables list the commonly used JFrame constructors and methods.

Other methods you might want to call are defined by the java. Frame , java. Window , and java. Component classes, from which JFrame descends. Because each JFrame object has a root pane, frames have support for interposing input and painting behavior in front of the frame children, placing children on different "layers", and for Swing menu bars. All of the standalone applications in this trail use JFrame.

The following table lists a few and tells you where each is discussed. All rights reserved. Hide TOC. Using Swing Components. Creating and Showing Frames Here is a picture of the extremely plain window created by the FrameDemo demonstration application.

The following FrameDemo code shows how to create and set up a frame. Create the frame. Optional: What happens when the frame closes? Create components and put them in the frame. Size the frame. Show it. Alternatively, to compile and run the example yourself, consult the example index. Bring up two windows, both with look-and-feel-provided decorations, but with different icons. The Java look and feel displays the icons in its window decorations.

Depending on your window system, the icon may be used elsewhere to represent the window, especially when the window is minimized.