stringitem.java

用于移动设备上的java虚拟机源代码

     */
    int callPreferredHeight(int w) {
        if (w == -1) {
            w = DEFAULT_WIDTH;
        }

        if (isButton()) {
            int buttonPad = 2 * (BUTTON_BORDER + BUTTON_PAD);
            int prefH     = Text.getTwoStringsHeight(label, str, 
                                                     LABEL_FONT, font,
                                                     w - buttonPad, 
                                                     LABEL_PAD);
            return (prefH > 0 ? prefH + buttonPad : 0);
        }

        return Text.getTwoStringsHeight(label, str, LABEL_FONT, font,
                                        w, LABEL_PAD);
    }

    /**
     * Determine if this Item should have a newline before it
     *
     * @return true if it should have a newline before
     */
    boolean equateNLB() {

        // If label starts with a\n,
        // put this StringItem on a newline no matter what
        if (label != null && label.length() > 0) {
            if (label.charAt(0) == '\n') {
                return true;
            }
        } else if (str != null && str.length() > 0) {
            // If there is no label and our content starts with a \n,
            // this StringItem starts on a newline
            if (str.charAt(0) == '\n') {
                return true;
            }
        } else {
            // empty StringItem
            return false;
        }

        if ((layout & Item.LAYOUT_2) == Item.LAYOUT_2) {
            return ((layout & Item.LAYOUT_NEWLINE_BEFORE)
                            == Item.LAYOUT_NEWLINE_BEFORE);
        }
            
        // in MIDP1.0 new any StringItem with a non-null label would
        // go on a new line
        return label != null && label.length() > 0;
    }

    /**
     * Determine if this Item should have a newline after it
     *
     * @return true if it should have a newline after
     */
    boolean equateNLA() {

        // If content ends with a \n,
        // there is a newline after this StringItem no matter what
        if (str != null && str.length() > 0) {
            if (str.charAt(str.length() - 1) == '\n') {
                return true;
            }
        } else if (label != null && label.length() > 0) {
            // If there is no content and our label ends with a \n, 
            // there is a newline after this StringItem
            if (label.charAt(label.length() - 1) == '\n') {
                return true;
            }
        } else {
            // empty StringItem
            return false;
        }

        if ((layout & Item.LAYOUT_2) == Item.LAYOUT_2) {
            return ((layout & Item.LAYOUT_NEWLINE_AFTER)
                            == Item.LAYOUT_NEWLINE_AFTER);
        }
        return false;
    }

    /**
     * Determine if Form should not traverse to this StringItem
     *
     * @return true if Form should not traverse to this StringItem
     */
    boolean shouldSkipTraverse() {
        if ((label == null || label.length() == 0) && 
            (str == null || str.length() == 0)) {
            return true;
        }

        return skipTraverse;
    }

    /**
     * Paint this StringItem
     *
     * @param g the Graphics object to paint to
     * @param width the width of this item
     * @param height the height of this item
     */
    void callPaint(Graphics g, int width, int height) {

        int w = width;
        int h = height;
        
        int translateY = 0;
        int translateX = 0;

        if (isButton()) {
            translateX = translateY = BUTTON_BORDER + BUTTON_PAD;
            w -= 2*translateX;
            h -= 2*translateY;
            g.translate(translateX, translateY);
        }

        Font lFont = (LABEL_BOLD_ON_TRAVERSE && !hasFocus) ?
                     Screen.CONTENT_FONT : LABEL_FONT;

        int labelHeight = getLabelHeight(w);

        int offset = Text.paint(label, lFont, 
                                g, w, labelHeight, 0, Text.NORMAL, null);
        if (offset > 0) {
            offset += LABEL_PAD;
        }

        int mode = Text.NORMAL;
        if (numCommands > 0 && appearanceMode == Item.HYPERLINK) { 
            mode = hasFocus ? (Text.INVERT | Text.HYPERLINK) :
                              (Text.NORMAL | Text.HYPERLINK);
        }

        int yOffset = labelHeight;
        if (labelHeight > 0) {
            yOffset -= (lFont.getHeight() < font.getHeight() ?
                        lFont.getHeight() : font.getHeight());
        }

        g.translate(0, yOffset);
        translateY += yOffset;

        Text.paint(str, font, g, w, h - yOffset, offset, mode, null);

        g.translate(-translateX, -translateY);

        if (isButton()) {
            drawButtonBorder(g, 0, 0, width, height, hasFocus);
        }
    }

    /**
     * Called by the system to signal a key press
     *
     * @param keyCode the key code of the key that has been pressed
     * @see #getInteractionModes
     */
    void callKeyPressed(int keyCode) {
        if (keyCode != Display.KEYCODE_SELECT) {
            return;
        }

        // StringItem takes focus only if there are one or more Item Commands
        // attached to it
        if (!(getCommandCount() > 0) || commandListener == null) {
            return;
        }

        ItemCommandListener cl = null;
        Command defaultCmd = null;

        synchronized (Display.LCDUILock) {
            cl = commandListener;
            defaultCmd = defaultCommand;
        } // synchronized

        // SYNC NOTE: The call to the listener must occur outside
        // of the lock
        if (cl != null) {
            try {
                // SYNC NOTE: We lock on calloutLock around any calls
                // into application code
                synchronized (Display.calloutLock) {
                    if (defaultCmd != null) {
                        cl.commandAction(defaultCmd, this);
                    } else {
                        // REMINDER : Needs HI decision
                        // either call the first command
                        // from  the command list or
                        // invoke the menu
                    }
                }
            } catch (Throwable thr) {
                Display.handleThrowable(thr);
            }
        }
    }

    /**
     *  Adds a context sensitive Command to the item.
     * @param cmd the command to be removed
     */
    void addCommandImpl(Command cmd) {
        synchronized (Display.LCDUILock) {
            // The super class will update the command set of the Form
            super.addCommandImpl(cmd);

            if ((numCommands >= 1) && (appearanceMode == Item.PLAIN)) {
                // restore the value of the original appearanceMode
                // if it is a button
                // otherwise simple change the appearanceMode
                // to hyperlink
                this.appearanceMode =
                    originalAppearanceMode == Item.BUTTON ?
                    Item.BUTTON : Item.HYPERLINK;
            }

            checkTraverse();
            invalidate();
        } // synchronized
    }

    /**
     *  Removes the context sensitive command from item.
     * @param cmd the command to be removed
     */
    void removeCommandImpl(Command cmd) {
        synchronized (Display.LCDUILock) {
            // The super class will update the command set of the Form
            super.removeCommandImpl(cmd);

            if ((numCommands < 1) && (appearanceMode != Item.PLAIN)) {
                // store value of the original appearanceMode
                originalAppearanceMode = this.appearanceMode;
                // change the appearanceMode to plain
                this.appearanceMode = Item.PLAIN;
            }

            checkTraverse();
            invalidate();
        } // synchronized
    }

    /**
     * Check that given the label, text, and commands, Form
     * should traverse this StringItem. Updates the internal
     * 'skipTraverse' variable.
     */
    private void checkTraverse() {
        if (str == null && label == null) {
            skipTraverse = true;
        } else if (str == null && label.trim().equals("")) {
            skipTraverse = true;
        } else if (label == null && str.trim().equals("")) {
            skipTraverse = true;
        } else {
            skipTraverse = false;
        }
    }

    /**
     * Determines if this StringItem should be rendered with the button border.
     * @return true if the StringItem should be rendered with 
     *         the button border, false - otherwise
     */
    private boolean isButton() {
        return (numCommands > 0 && appearanceMode == Item.BUTTON);
    }

    /** The text of this StringItem */
    private String str;

    /** The Font to render this StringItem's text in */
    private Font font;

    /** The appearance hint */
    private int appearanceMode;

    /** The original appearance hint before switching */
    private int originalAppearanceMode;

    /** Minimum height for one line */
    private int minimumLineHeight;

    /**
     * An internal flag. True if Form should not traverse
     * to this StringItem
     */
    private boolean skipTraverse;
  
}