displayable.java

来自「This is a resource based on j2me embedde」· Java 代码 · 共 502 行 · 第 1/2 页

     * affects the set of visible commands, the implementation should update 
     * the display as soon as it is feasible to do so.
     * If <code>cmd</code> is <code>null</code>, this method
     * does nothing.
     * 
     * @param cmd the command to be removed
     */
    public void removeCommand(Command cmd) {
        synchronized (Display.LCDUILock) {
            int i = removeCommandImpl(cmd);
            if (i != -1) {
                displayableLF.lRemoveCommand(cmd, i);
            }
        }
    }

    /**
     * Sets a listener for {@link Command Commands} to this
     * <code>Displayable</code>,
     * replacing any previous <code>CommandListener</code>. A
     * <code>null</code> reference is
     * allowed and has the effect of removing any existing listener.
     *
     * @param l the new listener, or <code>null</code>.
     */
    public void setCommandListener(CommandListener l) {
        synchronized (Display.LCDUILock) {
            listener = l;
        }
	displayableLF.updateCommandSet();
    }

    /**
     * Gets the width in pixels of the displayable area available to the 
     * application.  The value returned is appropriate for the particular 
     * <code>Displayable</code> subclass.  This value may depend
     * on how the device uses the
     * display and may be affected by the presence of a title, a ticker, or 
     * commands.
     * This method returns the proper result at all times, even if the
     * <code>Displayable</code> object has not yet been shown.
     * 
     * @return width of the area available to the application
     */
    public int getWidth() {
        synchronized (Display.LCDUILock) {
            return displayableLF.lGetWidth();
        }
    }

    /**
     * Gets the height in pixels of the displayable area available to the 
     * application.  The value returned is appropriate for the particular 
     * <code>Displayable</code> subclass.  This value may depend
     * on how the device uses the
     * display and may be affected by the presence of a title, a ticker, or 
     * commands.
     * This method returns the proper result at all times, even if the
     * <code>Displayable</code> object has not yet been shown.
     * 
     * @return height of the area available to the application
     */
    public int getHeight() {
        synchronized (Display.LCDUILock) {
            return displayableLF.lGetHeight();
        }
    }

// ************************************************************
//  protected methods
// ************************************************************

    /**
     * The implementation calls this method when the available area of the
     * <code>Displayable</code> has been changed. 
     * The &quot;available area&quot; is the area of the display that
     * may be occupied by
     * the application's contents, such as <code>Items</code> in a
     * <code>Form</code> or graphics within
     * a <code>Canvas</code>.  It does not include space occupied
     * by a title, a ticker,
     * command labels, scroll bars, system status area, etc.  A size change
     * can occur as a result of the addition, removal, or changed contents of 
     * any of these display features.
     *
     * <p> This method is called at least once before the
     * <code>Displayable</code> is shown for the first time.
     * If the size of a <code>Displayable</code> changes while
     * it is visible,
     * <CODE>sizeChanged</CODE> will be called.  If the size of a
     * <code>Displayable</code>
     * changes while it is <em>not</em> visible, calls to
     * <CODE>sizeChanged</CODE> may be deferred.  If the size had changed
     * while the <code>Displayable</code> was not visible,
     * <CODE>sizeChanged</CODE> will be
     * called at least once at the time the
     * <code>Displayable</code> becomes visible once
     * again.</p>
     *
     * <p>The default implementation of this method in <code>Displayable</code>
     * and its
     * subclasses defined in this specification must be empty.
     * This method is intended solely for being overridden by the
     * application. This method is defined on <code>Displayable</code>
     * even though applications are prohibited from creating 
     * direct subclasses of <code>Displayable</code>.
     * It is defined here so that applications can override it in
     * subclasses of <code>Canvas</code> and <code>Form</code>.
     * This is useful for <code>Canvas</code> subclasses to tailor
     * their graphics and for <code>Forms</code> to modify
     * <code>Item</code> sizes and layout
     * directives in order to fit their contents within the the available
     * display area.</p>
     * 
     * @param w the new width in pixels of the available area
     * @param h the new height in pixels of the available area
     */ 
    protected void sizeChanged(int w, int h) {
        // this method is intended to be overridden by the application
    }

// ************************************************************
//  package private methods
// ************************************************************

    /**
     * Gets look&feel for this Displayable object
     * This method is implemented in the subclasses.
     * @return - DisplayableLF for this Displayable object
     */
    DisplayableLF getLF() {
        return displayableLF;
    }


    /**
     * Called to schedule a call to itemStateChanged() due to
     * a change in the given Item.
     *
     * @param src the Item which has changed
     */
    void itemStateChanged(Item src) {
        /*
         * This call could happen on a Displayable that is not currently
         * visible (either not current, or the Display instance is not
         * foreground).
         */
        Display.itemStateChanged(src);
    }


    /**
     * Called by the event handler to notify any ItemStateListener
     * of a change in the given Item. 
     * The default implementation of this function does nothing.
     *
     * @param src The Item which has changed
     */
    void uCallItemStateChanged(Item src) { }


    /**
     * Add a Command to this Displayable
     *
     * @param cmd The Command to add to this Displayable
     * @return command index
     */
    int addCommandImpl(Command cmd) {
        for (int i = 0; i < numCommands; ++i) {
            if (commands[i] == cmd) {
                return -1;
            }
        }

        if ((commands == null) || (numCommands == commands.length)) {
            Command[] newCommands = new Command[numCommands + 4];
            if (commands != null) {
                System.arraycopy(commands, 0, newCommands, 0, numCommands);
            }
            commands = newCommands;
        }

        commands[numCommands] = cmd;
        ++numCommands;

        return numCommands-1;
    }

    /**
     * Remove a Command from this Displayable
     *
     * @param cmd The Command to remove from this Displayable
     * @return command index
     */
    int removeCommandImpl(Command cmd) {
        for (int i = 0; i < numCommands; ++i) {
            if (commands[i] == cmd) {
                commands[i] = commands[--numCommands];
                commands[numCommands] = null;
                return i;
            }
        }

        return -1;
    }

// ************************************************************
//  private methods
// ************************************************************
    
// ************************************************************
//  package private member variables
// ************************************************************

    /** An array of Commands added to this Displayable */
    Command commands[];

    /** The number of Commands added to this Displayable */
    int numCommands;

    /** The CommandListener for Commands added to this Displayable */
    CommandListener listener;

    /** True, if this Displayable is in full screen mode */
    boolean isInFullScreenMode; // = false

    /** True, if this Displayable is rotated */
    boolean isRotated; // = false

    /** The title for this Displayable */
    String title;

    /** The ticker that may be set for this Displayable */
    Ticker ticker;

    /** The Look &amps; Feel object associated with this Displayable */
    DisplayableLF displayableLF;


// ************************************************************
//  private member variables
// ************************************************************


// ************************************************************
//  Static initializer, constructor
// ************************************************************

} // Displayable