list.java

用于移动设备上的java虚拟机源代码

        if (!(listType == IMPLICIT   ||
              listType == EXCLUSIVE  ||
              listType == MULTIPLE)) {
            throw new IllegalArgumentException();
        }

        synchronized (Display.LCDUILock) {

            cg = new ChoiceGroup(null, listType,
                                 stringElements, imageElements, true);
            cg.isList = true;

            form = new Form(title);
            form.paintDelegate = this;
            form.append(cg);
        }
    }

    // public methods //

    /**
     * Sets a ticker for use with this <code>Displayable</code>,
     * replacing any
     * previous ticker.
     * If <code>null</code>, removes the ticker object
     * from this <code>Displayable</code>. The same ticker may be shared by
     * several <code>Displayable</code>
     * objects within an application. This is done by calling
     * <code>setTicker()</code>
     * with the same <code>Ticker</code> object on several
     * different <code>Displayable</code> objects.
     * If the <code>Displayable</code> is actually visible on the display,
     * the implementation should update
     * the display as soon as it is feasible to do so.
     *
     * <p>The existence of a ticker may affect the size
     * of the area available for <code>Displayable's</code> contents.
     * If the application adds, removes, or sets the ticker text at runtime,
     * this can dynamically change the size of the content area.
     * This is most important to be aware of when using the
     * <code>Canvas</code> class.
     *
     * @param ticker the ticker object used on this screen
     * @since MIDP 2.0
     * @see #getTicker
     */
    public void setTicker(Ticker ticker) {
        super.setTicker(ticker);

        // We override this method from Displayable to set the ticker
        // on our internal Form which is doing all our rendering

        form.setTicker(ticker);
    }

    /**
     * Sets the title of the <code>Displayable</code>. If
     * <code>null</code> is given,
     * removes the title.
     *
     * <P>If the <code>Displayable</code> is actually visible on
     * the display,
     * the implementation should update
     * the display as soon as it is feasible to do so.</P>
     *
     * <P>The existence of a title  may affect the size
     * of the area available for <code>Displayable</code> content.
     * If the application adds, removes, or sets the title text at runtime,
     * this can dynamically change the size of the content area.
     * This is most important to be aware of when using the
     * <code>Canvas</code> class.</p>
     *
     * @param s the new title, or <code>null</code> for no title
     * @since MIDP 2.0
     * @see #getTitle
     */
    public void setTitle(String s) {
        super.setTitle(s);

        // We override this method from Displayable to set the title
        // on our internal Form which is doing all our rendering

        form.setTitle(s);
    }

    /**
     * Gets the number of elements in the <code>List</code>.
     * @return the number of elements in the <code>List</code>
     */
    public int size() {
        return cg.size();
    }

    /**
     * Gets the <code>String</code> part of the element referenced by
     * <code>elementNum</code>.
     * 
     * @param elementNum the index of the element to be queried
     * @return the string part of the element
     * @throws IndexOutOfBoundsException if <code>elementNum</code> is invalid
     * @see #getImage(int)
     */
    public String getString(int elementNum) {
        return cg.getString(elementNum);
    }

    /**
     * Gets the <code>Image</code> part of the element referenced by
     * <code>elementNum</code>.
     *
     * @param elementNum the number of the element to be queried
     * @return the image part of the element, or <code>null</code>
     * if there is no image
     * @throws IndexOutOfBoundsException if <code>elementNum</code> is invalid
     * @see #getString(int)
     */
    public Image getImage(int elementNum) {
        return cg.getImage(elementNum);
    }

    /**
     * Appends an element to the <code>List</code>.
     * 
     * @param stringPart the string part of the element to be added
     * @param imagePart the image part of the element to be added, or
     * <code>null</code> if there is no image part
     * @return the assigned index of the element
     * @throws NullPointerException if <code>stringPart</code> is
     * <code>null</code>
     */
    public int append(String stringPart, Image imagePart) {
        return cg.append(stringPart, imagePart);
    }

    /**
     * Inserts an element into the <code>List</code> just prior to
     * the element specified.
     * 
     * @param elementNum the index of the element where insertion is to occur
     * @param stringPart the string part of the element to be inserted
     * @param imagePart the image part of the element to be inserted,
     * or <code>null</code> if there is no image part
     * @throws IndexOutOfBoundsException if <code>elementNum</code> is invalid
     * @throws NullPointerException if <code>stringPart</code> is
     * <code>null</code>
     */
    public void insert(int elementNum,
                       String stringPart, Image imagePart) {
        cg.insert(elementNum, stringPart, imagePart);
    }

    /**
     * Deletes the element referenced by <code>elementNum</code>.
     * 
     * @param elementNum the index of the element to be deleted
     * @throws IndexOutOfBoundsException if <code>elementNum</code> is invalid
     */
    public void delete(int elementNum) {
        cg.delete(elementNum);
    }

    /**
     * Deletes all elements from this List.
     */
    public void deleteAll() {
        cg.deleteAll();
    }

    /**
     * Sets the <code>String</code> and <code>Image</code> parts of the
     * element referenced by <code>elementNum</code>,
     * replacing the previous contents of the element.
     * 
     * @param elementNum the index of the element to be set
     * @param stringPart the string part of the new element
     * @param imagePart the image part of the element, or <code>null</code>
     * if there is no image part
     *
     * @throws IndexOutOfBoundsException if <code>elementNum</code> is invalid
     * @throws NullPointerException if <code>stringPart</code> is
     * <code>null</code>
     */
    public void set(int elementNum, String stringPart, Image imagePart) {
        cg.set(elementNum, stringPart, imagePart);
    }

    /**
     * Gets a boolean value indicating whether this element is selected.
     * 
     * @param elementNum index to element to be queried
     *
     * @return selection state of the element
     *
     * @throws IndexOutOfBoundsException if <code>elementNum</code> is invalid
     */
    public boolean isSelected(int elementNum) {
        return cg.isSelected(elementNum);
    }

    /**
     * Returns the index number of an element in the <code>List</code>
     * that is selected.
     * 
     * @return index of selected element, or <code>-1</code> if none
     * @see #setSelectedIndex
     */
    public int getSelectedIndex() {
        return cg.getSelectedIndex();
    }

    /**
     * Queries the state of a <code>List</code> and returns the
     * state of all elements
     * in the
     * boolean array
     * <code>selectedArray_return</code>.
     * 
     * @param selectedArray_return array to contain the results
     *
     * @return the number of selected elements in the <code>Choice</code>
     *
     * @throws IllegalArgumentException if <code>selectedArray_return</code>
     * is shorter than the size of the List
     * @throws NullPointerException if <code>selectedArray_return</code> 
     * is <code>null</code>
     * @see #setSelectedFlags
     */
    public int getSelectedFlags(boolean[] selectedArray_return) {
        return cg.getSelectedFlags(selectedArray_return);
    }

    /**
     * Sets the selected state of an element.
     * 
     * @param elementNum the index of the element, starting from zero
     * @param selected the state of the element, where <code>true</code> means
     * selected and <code>false</code> means not selected
     * @throws IndexOutOfBoundsException if <code>elementNum</code> is invalid
     * @see #getSelectedIndex
     */
    public void setSelectedIndex(int elementNum, boolean selected) {
        cg.setSelectedIndex(elementNum, selected);
    }

    /**
     * Sets the selected state of all elements of the <code>List</code>.
     * 
     * @param selectedArray an array in which the method collect
     * the selection status
     * @throws IllegalArgumentException if <code>selectedArray</code> is
     * shorter than the size of the <code>List</code>
     * @throws NullPointerException if <code>selectedArray</code> is
     * <code>null</code>
     * @see #getSelectedFlags
     */
    public void setSelectedFlags(boolean[] selectedArray) {
        cg.setSelectedFlags(selectedArray);
    }

    /**
     * The same as {@link Displayable#removeCommand Displayable.removeCommand} 
     * but with the following additional semantics.
     * 
     * <p>If the command to be removed happens to be the select command, the
     * <code>List</code> is set to have no select command, and the command is
     * removed from the <code>List</code>.</p>
     *
     * <p>The following code: </P>
     * <TABLE BORDER="2">
     * <TR>
     * <TD ROWSPAN="1" COLSPAN="1">
     *    <pre><code>
     *     // Command c is the select command on List list    
     *     list.removeCommand(c);     </code></pre>
     * </TD>
     * </TR>
     * </TABLE>
     * <P>
     * is equivalent to the following code: </P>
     * <TABLE BORDER="2">
     * <TR>
     * <TD ROWSPAN="1" COLSPAN="1">