菜单滑动效果的实现

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<TextureRegion> columns = new ArrayList<TextureRegion>(); // =========================================================== // 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 < MENUITEMS; i++) { BitmapTextureAtlas mMenuBitmapTextureAtlas = new BitmapTextureAtlas(256,256, TextureOptions.BILINEAR_PREMULTIPLYALPHA); TextureRegion mMenuTextureRegion = BitmapTextureAtlasTextureRegionFactory.createFromAsset(mMenuBitmapTextureAtlas, this, "menu"+i+".png", 0, 0); this.mEngine.getTextureManager().loadTexture(mMenuBitmapTextureAtlas); columns.add(mMenuTextureRegion); } //Textures for menu arrows this.mMenuTextureAtlas = new BitmapTextureAtlas(128,128, TextureOptions.BILINEAR_PREMULTIPLYALPHA); this.mMenuLeftTextureRegion = BitmapTextureAtlasTextureRegionFactory.createFromAsset(mMenuTextureAtlas, this, "menu_left.png", 0, 0); this.mMenuRightTextureRegion = BitmapTextureAtlasTextureRegionFactory.createFromAsset(mMenuTextureAtlas, this, "menu_right.png",64, 0); this.mEngine.getTextureManager().loadTexture(mMenuTextureAtlas); } @Override public Engine onLoadEngine() { this.mCamera = new Camera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT); final EngineOptions engineOptions = new EngineOptions(true, ScreenOrientation.LANDSCAPE, new FillResolutionPolicy(), this.mCamera); engineOptions.getTouchOptions().setRunOnUpdateThread(true); final Engine engine = new Engine(engineOptions); return engine; } @Override public Scene onLoadScene() { this.mEngine.registerUpdateHandler(new FPSLogger()); this.mScene = new Scene(); this.mScene.setBackground(new ColorBackground(0, 0, 0)); this.mScrollDetector = new SurfaceScrollDetector(this); this.mClickDetector = new ClickDetector(this); this.mScene.setOnSceneTouchListener(this); this.mScene.setTouchAreaBindingEnabled(true); this.mScene.setOnSceneTouchListenerBindingEnabled(true); CreateMenuBoxes(); return this.mScene; } @Override public boolean onSceneTouchEvent(final Scene pScene, final TouchEvent pSceneTouchEvent) { this.mClickDetector.onTouchEvent(pSceneTouchEvent); this.mScrollDetector.onTouchEvent(pSceneTouchEvent); return true; } @Override public void onScroll(final ScrollDetector pScollDetector, final TouchEvent pTouchEvent, final float pDistanceX, final float pDistanceY) { //Disable the menu arrows left and right (15px padding) if(mCamera.getMinX()<=15) menuleft.setVisible(false); else menuleft.setVisible(true); if(mCamera.getMinX()>mMaxX-15) menuright.setVisible(false); else menuright.setVisible(true); //Return if ends are reached if ( ((mCurrentX - pDistanceX) < mMinX) ){ return; }else 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 < columns.size(); x++) { //On Touch, save the clicked item in case it's a click and not a scroll. final int itemToLoad = iItem; Sprite sprite = new Sprite(spriteX,spriteY,columns.get(x)){ public boolean onAreaTouched(final TouchEvent pSceneTouchEvent, final float pTouchAreaLocalX, final float pTouchAreaLocalY) { iItemClicked = itemToLoad; return false; } }; iItem++; this.mScene.attachChild(sprite); this.mScene.registerTouchArea(sprite); spriteX += 20 + PADDING+sprite.getWidth(); } mMaxX = spriteX - CAMERA_WIDTH; //set the size of the scrollbar float scrollbarsize = CAMERA_WIDTH/((mMaxX+CAMERA_WIDTH)/CAMERA_WIDTH); scrollBar = new Rectangle(0,CAMERA_HEIGHT-20,scrollbarsize, 20); scrollBar.setColor(1,0,0); this.mScene.attachChild(scrollBar); menuleft = new Sprite(0,CAMERA_HEIGHT/2-mMenuLeftTextureRegion.getHeight()/2,mMenuLeftTextureRegion); menuright = new Sprite(CAMERA_WIDTH-mMenuRightTextureRegion.getWidth(),CAMERA_HEIGHT/2-mMenuRightTextureRegion.getHeight()/2,mMenuRightTextureRegion); this.mScene.attachChild(menuright); menuleft.setVisible(false); this.mScene.attachChild(menuleft); } @Override public void onLoadComplete() { } //Here is where you call the item load. private void loadLevel(final int iLevel) { if (iLevel != -1) { runOnUiThread(new Runnable() { @Override public void run() { Toast.makeText(MenuScrollerActivity.this, "Load Item" + String.valueOf(iLevel), Toast.LENGTH_SHORT).show(); iItemClicked = -1; } }); } }}

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