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有沒有什麼辦法在j2me中創建一個標籤菜單？
我發現了一個代碼，但我無法理解它在j2me中創建Tabmenu
在這段代碼有創建的選項卡菜單，在Canvas類，然後選項卡菜單中創建它在畫布完全完成或油漆。我發現難以掌握的唯一部分是void go()方法，然後
當我嘗試使用繪圖方法在代碼上下繪製任何東西時，它不起作用 - 問題是什麼？
下面是代碼
// Tab Menu CANVAS class
import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Graphics;
public class TabMenuCanvas extends Canvas
{
TabMenu menu = null;
public TabMenuCanvas()
{
menu = new TabMenu(
new String[]{"Home", "News", "Community", "Your files", "Credits", "Events", "Blog", "Upload", "Forum Nokia"},
getWidth() - 20
);
}
protected void keyPressed(int key)
{
int gameAction = getGameAction(key);
if(gameAction == Canvas.RIGHT)
{
menu.goRight();
repaint();
}
else if(gameAction == Canvas.LEFT)
{
menu.goLeft();
repaint();
}
}
protected void paint(Graphics g)
{
g.translate(10, 30);
menu.paint(g);
g.translate(- 10, - 30);
}
}
// Tab Menu Class
import javax.microedition.lcdui.Font;
import javax.microedition.lcdui.Graphics;
public class TabMenu
{
int background = 0xffffff;
int bgColor = 0xcccccc;
int bgFocusedColor = 0x0000ff;
int foreColor = 0x000000;
int foreFocusedColor = 0xffffff;
int cornerRadius = 6;
int padding = 2;
int margin = 2;
Font font = Font.getDefaultFont();
int scrollStep = 20;
int selectedTab = 0; //selected tab index
int[] tabsWidth = null; //width of single tabs
int[] tabsLeft = null; //left X coordinate of single tabs
int tabHeight = 0; //height of tabs (equal for all tabs)
String[] tabs = null; //tab labels
int menuWidth = 0; //total menu width
int viewportWidth = 0; //visible viewport width
int viewportX = 0; //current viewport X coordinate
public TabMenu(String[] tabs, int width)
{
this.tabs = tabs;
this.viewportWidth = width;
initialize();
}
void initialize()
{
tabHeight = font.getHeight() + cornerRadius + 2 * padding; //[ same for all tabs]
menuWidth = 0;
tabsWidth = new int[tabs.length];
tabsLeft = new int[tabs.length];
for(int i = 0; i < tabsWidth.length; i++)
{
tabsWidth[i] = font.stringWidth(tabs[i]) + 2 * padding + 2 * cornerRadius;
tabsLeft[i] = menuWidth;
menuWidth += tabsWidth[i];
if(i > 0)
{
menuWidth += margin;
}
}
}
public void goRight()
{
go(+1);
}
public void goLeft()
{
go(-1);
}
private void go(int delta)
{
int newTab = Math.max(0, Math.min(tabs.length - 1, selectedTab + delta));
boolean scroll = true;
if(newTab != selectedTab && isTabVisible(newTab))
{
selectedTab = newTab;
if((delta > 0 && tabsLeft[selectedTab] + tabsWidth[selectedTab] > viewportX + viewportWidth) ||
(delta < 0 && tabsLeft[selectedTab] < viewportX))
{
scroll = true;
}
else
{
scroll = false;
}
}
if(scroll)
{
viewportX = Math.max(0, Math.min(menuWidth - viewportWidth, viewportX + delta * scrollStep));
}
}
private boolean isTabVisible(int tabIndex)
{
return tabsLeft[tabIndex] < viewportX + viewportWidth &&
tabsLeft[tabIndex] + tabsWidth[tabIndex] >= viewportX;
}
public void paint(Graphics g)
{
int currentX = - viewportX;
g.setClip(0, 0, viewportWidth, tabHeight);
g.setColor(background);
g.fillRect(0, 0, viewportWidth, tabHeight);
for(int i = 0; i < tabs.length; i++)
{
g.setColor(i == selectedTab ? bgFocusedColor : bgColor);
g.fillRoundRect(currentX, 0, tabsWidth[i], tabHeight + cornerRadius, 2 * cornerRadius, 2 * cornerRadius);
g.setColor(i == selectedTab ? foreFocusedColor : foreColor);
g.drawString(tabs[i], currentX + cornerRadius + padding, cornerRadius + padding, Graphics.LEFT | Graphics.TOP);
currentX += tabsWidth[i] + margin;
}
}
}