[Chapter 21] FocusEvent

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| Chapter 21 java.awt.event Reference |

# FocusEvent

## Name

FocusEvent

##

## Description

Focus events are generated when a component gets or loses input focus. Focus events come in two flavors, permanent and temporary. Permanent focus events occur with explicit focus changes. For example, when the user tabs through components, this causes permanent focus events. An example of a temporary focus event is when a component loses focus as its containing window is deactivated.

## Class Definition

    public class java.awt.event.FocusEvent
       extends java.awt.event.ComponentEvent {
      // Constants
      public final static int FOCUS_FIRST;
      public final static int FOCUS_GAINED;
      public final static int FOCUS_LAST;
      public final static int FOCUS_LOST;
      // Constructors
      public FocusEvent (Component source, int id);
      public FocusEvent (Component source, int id, boolean temporary);
      // Instance Methods
      public boolean isTemporary();
      public String paramString();
    }

## Constants

### FOCUS_FIRST

#### public final static int FOCUS_FIRST

Specifies the beginning range of focus event ID values.

### FOCUS_GAINED

#### public final static int FOCUS_GAINED

Event type ID indicating that the component gained the input focus.

### FOCUS_LAST

#### public final static int FOCUS_LAST

Specifies the ending range of focus event ID values.

### FOCUS_LOST

#### public final static int FOCUS_LOST

Event type ID indicating that the component lost the input focus.

## Constructors

### FocusEvent

#### public FocusEvent (Component source, int id)

Parameters

  source

    The object that generated the event.

  id

    The event type ID of the event.

Description

  Constructs a non-temporary `FocusEvent` with the given characteristics.

#### public FocusEvent (Component source, int id, boolean temporary)

Parameters

  source

    The object that generated the event.

  id

    The event type ID of the event.

  temporary

    A flag indicating whether this is a temporary focus event.

Description

  Constructs a `FocusEvent` with the given characteristics.

## Instance Methods

### isTemporary

#### public boolean isTemporary()

Returns

  `true` if this is a temporary focus event; `false` otherwise.

### paramString

#### public String paramString()

Returns

  String with current settings of the `FocusEvent`.

Overrides

  `ComponentEvent``.paramString()`

Description

  Helper method for `toString()` to generate string of current settings.

## See Also

`Component`, `ComponentEvent`, `FocusAdapter`, `FocusListener`

FocusAdapter |  | FocusListener