java实现菜单滑动效果

 public class MenuScrollerActivity extends BaseGameActivity implements IScrollDetectorListener, IOnSceneTouchListener, IClickDetectorListener { // =========================================================== // Constants // =========================================================== protected static int CAMERA_WIDTH = 480; protected static int CAMERA_HEIGHT = 320; protected static int FONT_SIZE = 24; protected static int PADDING = 50; protected static int MENUITEMS = 7; // =========================================================== // Fields // =========================================================== private Scene mScene; private Camera mCamera; private Font mFont; private BitmapTextureAtlas mFontTexture; private BitmapTextureAtlas mMenuTextureAtlas; private TextureRegion mMenuLeftTextureRegion; private TextureRegion mMenuRightTextureRegion; private Sprite menuleft; private Sprite menuright; // Scrolling private SurfaceScrollDetector mScrollDetector; private ClickDetector mClickDetector; private float mMinX = 0; private float mMaxX = 0; private float mCurrentX = 0; private int iItemClicked = -1; private Rectangle scrollBar; private List columns = new ArrayList(); // =========================================================== // Constructors // =========================================================== // =========================================================== // Getter & Setter // =========================================================== // =========================================================== // Methods for/from SuperClass/Interfaces // =========================================================== @Override public void onLoadResources() { // Paths FontFactory.setAssetBasePath("font/"); BitmapTextureAtlasTextureRegionFactory.setAssetBasePath("gfx/"); // Font this.mFontTexture = new BitmapTextureAtlas(256, 256); this.mFont = FontFactory.createFromAsset(this.mFontTexture, this, "Plok.TTF", FONT_SIZE, true, Color.BLACK); this.mEngine.getTextureManager().loadTextures(this.mFontTexture); this.mEngine.getFontManager().loadFonts(this.mFont); //Images for the menu for (int i = 0; i mMaxX-15) menuright.setVisible(false); else menuright.setVisible(true); //Return if ends are reached if ( ((mCurrentX - pDistanceX)  mMaxX){ return; } //Center camera to the current point this.mCamera.offsetCenter(-pDistanceX,0 ); mCurrentX -= pDistanceX; //Set the scrollbar with the camera float tempX =mCamera.getCenterX()-CAMERA_WIDTH/2; // add the % part to the position tempX+= (tempX/(mMaxX+CAMERA_WIDTH))*CAMERA_WIDTH; //set the position scrollBar.setPosition(tempX, scrollBar.getY()); //set the arrows for left and right menuright.setPosition(mCamera.getCenterX()+CAMERA_WIDTH/2-menuright.getWidth(),menuright.getY()); menuleft.setPosition(mCamera.getCenterX()-CAMERA_WIDTH/2,menuleft.getY()); //Because Camera can have negativ X values, so set to 0 if(this.mCamera.getMinX()<0){ this.mCamera.offsetCenter(0,0 ); mCurrentX=0; } } @Override public void onClick(ClickDetector pClickDetector, TouchEvent pTouchEvent) { loadLevel(iItemClicked); }; // =========================================================== // Methods // =========================================================== private void CreateMenuBoxes() { int spriteX = PADDING; int spriteY = PADDING; //current item counter int iItem = 1; for (int x = 0; x