Module java.desktop
Package java.awt

Class Label

All Implemented Interfaces:
ImageObserver, MenuContainer, Serializable, Accessible

public class Label
extends Component
implements Accessible
A Label object is a component for placing text in a container. A label displays a single line of read-only text. The text can be changed by the application, but a user cannot edit it directly.

For example, the code . . .


 setLayout(new FlowLayout(FlowLayout.CENTER, 10, 10));
 add(new Label("Hi There!"));
 add(new Label("Another Label"));
 

produces the following labels:

Two labels: 'Hi There!' and
 'Another label'

Since:
1.0
See Also:
Serialized Form
  • Field Details

    • LEFT

      public static final int LEFT
      Indicates that the label should be left justified.
      See Also:
      Constant Field Values
    • CENTER

      public static final int CENTER
      Indicates that the label should be centered.
      See Also:
      Constant Field Values
  • Constructor Details

    • Label

      public Label() throws HeadlessException
      Constructs an empty label. The text of the label is the empty string "".
      Throws:
      HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
      See Also:
      GraphicsEnvironment.isHeadless()
    • Label

      public Label​(String text) throws HeadlessException
      Constructs a new label with the specified string of text, left justified.
      Parameters:
      text - the string that the label presents. A null value will be accepted without causing a NullPointerException to be thrown.
      Throws:
      HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
      See Also:
      GraphicsEnvironment.isHeadless()
    • Label

      public Label​(String text, int alignment) throws HeadlessException
      Constructs a new label that presents the specified string of text with the specified alignment. Possible values for alignment are Label.LEFT, Label.RIGHT, and Label.CENTER.
      Parameters:
      text - the string that the label presents. A null value will be accepted without causing a NullPointerException to be thrown.
      alignment - the alignment value.
      Throws:
      HeadlessException - if GraphicsEnvironment.isHeadless() returns true.
      See Also:
      GraphicsEnvironment.isHeadless()
  • Method Details

    • addNotify

      public void addNotify()
      Creates the peer for this label. The peer allows us to modify the appearance of the label without changing its functionality.
      Overrides:
      addNotify in class Component
      See Also:
      Component.isDisplayable(), Component.removeNotify(), Component.invalidate()
    • getAlignment

      public int getAlignment()
      Gets the current alignment of this label. Possible values are Label.LEFT, Label.RIGHT, and Label.CENTER.
      Returns:
      the alignment of this label
      See Also:
      setAlignment(int)
    • setAlignment

      public void setAlignment​(int alignment)
      Sets the alignment for this label to the specified alignment. Possible values are Label.LEFT, Label.RIGHT, and Label.CENTER.
      Parameters:
      alignment - the alignment to be set.
      Throws:
      IllegalArgumentException - if an improper value for alignment is given.
      See Also:
      getAlignment()
    • getText

      public String getText()
      Gets the text of this label.
      Returns:
      the text of this label, or null if the text has been set to null.
      See Also:
      setText(java.lang.String)
    • setText

      public void setText​(String text)
      Sets the text for this label to the specified text.
      Parameters:
      text - the text that this label displays. If text is null, it is treated for display purposes like an empty string "".
      See Also:
      getText()
    • paramString

      protected String paramString()
      Returns a string representing the state of this Label. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.
      Overrides:
      paramString in class Component
      Returns:
      the parameter string of this label
    • getAccessibleContext

      public AccessibleContext getAccessibleContext()
      Gets the AccessibleContext associated with this Label. For labels, the AccessibleContext takes the form of an AccessibleAWTLabel. A new AccessibleAWTLabel instance is created if necessary.
      Specified by:
      getAccessibleContext in interface Accessible
      Overrides:
      getAccessibleContext in class Component
      Returns:
      an AccessibleAWTLabel that serves as the AccessibleContext of this Label
      Since:
      1.3