AWT.pptx
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The document discusses Java Abstract Window Toolkit (AWT) which provides components to build graphical user interfaces. It describes that AWT components are platform dependent and heavy weight since they are built on top of native OS components. It then discusses the AWT component hierarchy including common components like buttons, text fields and containers like frames and panels that hold components. Specific AWT container types and common methods for working with AWT components are also summarized.
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AWT.pptx
- 1. AWT
- 2. • Java AWT (Abstract Window Toolkit) • It is an API to develop Graphical User Interface (GUI) or windows-based applications in Java. • Java AWT components are platform-dependent i.e. components are displayed according to the view of operating system. AWT is heavy weight i.e. its components are using the resources of underlying operating system (OS). • The java.awt package provides classes for AWT API such as TextField, Label, TextArea, RadioButton, CheckBox, Choice, List etc. • For example, an AWT GUI with components like TextField, label and button will have different look and feel for the different platforms like Windows, MAC OS, and Unix.
- 4. Components • All the elements like the button, text fields, scroll bars, etc. are called components. • In Java AWT, there are classes for each component as shown in above diagram. • In order to place every component in a particular position on a screen, we need to add them to a container.
- 5. Container • The Container is a component in AWT that can contain another components like buttons, textfields, labels etc. • The classes that extends Container class are known as container such as Frame, Dialog and Panel. • It is basically a screen where the where the components are placed at their specific locations. • Thus it contains and controls the layout of components.
- 6. • There are four types of containers in Java AWT: 1.Window 2.Panel 3.Frame 4.Dialog • Window The window is the container that have no borders and menu bars. You must use frame, dialog or another window for creating a window. We need to create an instance of Window class to create this container.
- 7. • Panel The Panel is the container that doesn't contain title bar, border or menu bar. It is generic container for holding the components. It can have other components like button, text field etc. An instance of Panel class creates a container, in which we can add components. • Frame The Frame is the container that contain title bar and border and can have menu bars. It can have other components like button, text field, scrollbar etc. Frame is most widely used container while developing an AWT application.
- 8. Method Description public void add(Component c) Inserts a component on this component. public void setSize(int width,int height) Sets the size (width and height) of the component. public void setLayout(LayoutManager m) Defines the layout manager for the component. public void setVisible(boolean status) Changes the visibility of the component, by default false.
- 9. / importing Java AWT class import java.awt.*; // class AWTExample2 directly creates instance of Frame class class AWTExample2 { // initializing using constructor AWTExample2() { // creating a Frame Frame f = new Frame(); // creating a Label Label l = new Label("Employee id:"); // creating a Button Button b = new Button("Submit"); // creating a TextField TextField t = new TextField(); // setting position of above components in the frame l.setBounds(20, 80, 80, 30); t.setBounds(20, 100, 80, 30); b.setBounds(100, 100, 80, 30);
- 10. // adding components into frame f.add(b); f.add(l); f.add(t); // frame size 300 width and 300 height f.setSize(400,300); // setting the title of frame f.setTitle("Employee info"); // no layout f.setLayout(null); // setting visibility of frame f.setVisible(true); } // main method public static void main(String args[]) { // creating instance of Frame class AWTExample2 awt_obj = new AWTExample2(); } }
- 11. output