Unit Vii Awtcontrols&swings

AWT Controls And Swings Buttons: Buttons can be created in java using the Buttons class in java.awt package. Constructors: Button() Button(String label) Methods: public void setLabel(String label) public void addActionListener(ActionListener object) public void setActionCommand(String actionCommand) public String getActionCommand() Button button1 = new Button (); button1.setLabel(“OK”); Button button2 = new Button(“Cancel”); Ex: import java.awt.Frame; import java.awt.Button; import java.awt.FlowLayout; class Test extends Frame{ public Test(String title){ super(title); Button button1 = new Button (); button1.setLabel("OK"); Button button2 = new Button("Cancel"); setLayout(new FlowLayout()); add(button1); add(button2); setSize(300,300); setVisible(true); } public static void main(String args[]){ new Test(“Button Demo); } } Ouput:

Label: A Label object is a component for placing text in a container. A label displays a single line of read-only text. Constructors: Label() Label(String text) Label(String text, int alignment) Constants: public static final int CENTER public static final int LEFT public static final int RIGHT Methods: public void setText(String text) public String getText() public void setAlignment(int alignment) public int getAlignment() Ex: class Test extends Frame{ public Test(String title){ super(title); Label label1 = new Label(); label1.setText("Label 1"); Label label2 = new Label("Label 2", Label.RIGHT); Label label3 = new Label("Label3"); setLayout(new FlowLayout()); add(label1); add(label2); add(label3); setSize(300,100); setVisible(true); }

public static void main(String args[]){ new Test("Label Demo"); } } Ouput:

TextField & TextArea: TextField: A TextField object is a text component that allows for the editing of a single line of text. Constructors: TextArea: A TextArea object is a text component that allows for the editing/displaying of multiple lines of text. It can be set to allow editing or to be read-only. Ex: import java.awt.Frame; import java.awt.Button; import java.awt.Label; import java.awt.TextField; import java.awt.TextArea; import java.awt.FlowLayout; import java.awt.event.*; class TextComponentsDemo extends Frame implements ActionListener{ TextField tf1; Button b1; TextArea ta; public TextComponentsDemo(String title){ super(title); Label label1 = new Label("Enter ur name: "); tf1 = new TextField(20); b1 = new Button("OK"); ta = new TextArea(10,10); b1.addActionListener(this);

tf1.addActionListener(this); setLayout(new FlowLayout()); add(label1); add(tf1); add(b1); add(ta); setSize(300,250); setVisible(true); } public void actionPerformed(ActionEvent ae){ if(ae.getSource()==b1 || ae.getSource()==tf1) ta.setText(tf1.getText()); } public static void main(String args[]){ new TextComponentsDemo ("Text components Demo"); } }

Check box & CheckBox group: Check Box: A check box is a graphical component that can be in either an "on" (true) or "off" (false) state. Clicking on a check box changes its state from "on" to "off," or from "off" to "on." Check Box group: The CheckboxGroup class is used to group together a set of Checkbox buttons. Ex: import java.awt.Frame; import java.awt.Font; import java.awt.Label; import java.awt.Checkbox; import java.awt.FlowLayout; import java.awt.event.*; class CheckboxDemo extends Frame implements ItemListener{ Checkbox cb1,cb2,cb3; Label l1;

Font f; String text="This text is now "; public Test(String title){ super(title); cb1 = new Checkbox("Plain",true); cb2 = new Checkbox("Bold",false); cb3 = new Checkbox("Italic",false); f = new Font("TimesNewRoman", Font.PLAIN,12); this.setFont(f); l1 = new Label(text); cb1.addItemListener(this); cb2.addItemListener(this); cb3.addItemListener(this); setLayout(new FlowLayout()); add(l1); add(cb1); add(cb2); add(cb3); setSize(300,250); setVisible(true); } public void itemStateChanged(ItemEvent ie){ if(ie.getSource()==cb1 && cb1.isSelected()) l1.setFont(new Font("TimesNewRoman", l1.getStyle() +Font.BOLD,12)); else if(ie.getSource()==cb2 && cb2.isSelected()) l1.setFont(new Font("TimesNewRoman", l1.getStyle() +Font.BOLD,12)); else if(cb3.isSelected()) l1.setFont(new Font("TimesNewRoman", l1.getStyle() +Font.ITALIC,12)); } public static void main(String args[]){ new Test("Text components Demo");

} }