Java windows gui

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. The ActionEvent listener is required to implement the ActionListener interface, and override the actionPerformed method to provide the programmed response upon activation.

We identify the super Frame as the source object. It is required to implement the WindowListener interface, which declares 7 abstract methods: windowOpened , windowClosed , windowClosing , windowActivated , windowDeactivated , windowIconified and windowDeiconified. We override the windowClosing handler to terminate the program using System.

We ignore the other 6 handlers, but required to provide an empty body for compilation. The sequence diagram is as follow: Example 4: MouseEvent and MouseListener Interface A MouseEvent is fired when you press, release, or click press followed by release a mouse-button left or right button at the source object; or position the mouse-pointer at enter and away exit from the source object.

To demonstrate the MouseEvent : We identity super Frame as the source object. It is required to implement the MouseListener interface, which declares 5 abstract methods: mouseClicked , mousePressed , mouseReleased , mouseEntered , and mouseExit.

We override the mouseClicked to display the x, y coordinates of the mouse click on the two displayed TextField s. We ignore all the other handlers for simplicity - but you need to provide an empty body for compilation. We override the mouseMoved to display the x, y position of the mouse pointer. We ignore the MouseDragged handler by providing an empty body for compilation. Example 6: KeyEvent and KeyListener Interface A KeyEvent is fired when you pressed, released, and typed pressed followed by released a key on the source object.

The KeyEvent listener needs to implement the KeyListener interface, which declares 3 abstract methods: keyTyped , keyPressed , keyReleased.

We override the keyTyped to display key typed on the display TextArea. We ignore the keyPressed and keyReleased. An example is as follows: import java. What are Inner classes? That is, it could contain constructors, member variables and member methods. You can create an instance of a nested class via the new operator and constructor. A nested class is a member of the outer class, just like any member variables and methods defined inside a class.

This is the property that makes inner class useful. Step 5 Add two buttons How about adding two buttons?

Copy the following code into an editor. There are many layout managers, but the most frequently used are-. A BorderLayout places components in up to five areas: top, bottom, left, right, and center.

It is the default layout manager for every java JFrame. FlowLayout is the default layout manager for every JPanel. It simply lays out components in a single row one after the other. It is the more sophisticated of all layouts. Based on my investigation and theory It's failing due to windows doesn't have a GUI when using task scheduler.

So my question is there a workaround for windows to run the task scheduler and allow the Java app that I've created to allow automatic GUI interaction. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 3 days ago. Active 2 days ago.

Viewed 35 times. If you wish to create a rich user interface, AWT is not the best option. The components in Swing are also less resource intensive compare to AWT. It would be rare to see a new GUI project nowadays using Swing.

Even now in it likely still holds a significant portion of the total GUI developers in Java. Of course, it has its own downsides too when compared to Swing such as requiring native DLLs across different systems. An older library like Swing has the advantage of being older and has had time to fully mature and develop as a GUI framework.