游戏中，我们常常要处理场景中Sprite的前后遮挡关系。

以下公式根据TileMap坐标来动态计算ZOrder，来确保正确的遮挡关系。

为了计算的高效率，使用了位移来代替乘法运算。

        // 最小左位移
        int shifting = 6;
        int height = map->getMapHeight();
        if (height > 512) {
            // 超过2^8
            shifting = 10;
        }else if (height > 256) {
            // 超过2^7
            shifting = 9;
        }else if (height > 128) {
            // 超过2^6
            shifting = 8;
        }else if (height > 64) {
            // 超过2^5
            shifting = 7;
        }
        // 根据TileMap坐标系来确定ZOrder
        _sprite->setZOrder((posTile.x + posTile.y) - (map->getMapWidth() << shifting));

注：谨以此文表达对某大企业鸡蛋里挑骨头的作风表示强列不满！

软件需求变更是常有的事，当然有些合理，有此不合理，如何判断就见仁见智了

先上图：

先说明下，这是android4.2锁屏的界面。左边是4.2的新特性，可以添加WIDGET。

问题：唤醒屏时不应该有这个显示

首先，了解下为什么会有“这个”显示

代码在：

frameworks/base/policy/src/com/android/internal/policy/impl/keyguard/KeyguardViewStateManager.java

    private Runnable mHideHintsRunnable = new Runnable() {
        @Override
        public void run() {
            if (mKeyguardWidgetPager != null) {
                mKeyguardWidgetPager.hideOutlinesAndSidePages();
            }
        }
    };

    public void showUsabilityHints() {
        mMainQueue.postDelayed( new Runnable() {
            @Override
            public void run() {
                mKeyguardSecurityContainer.showUsabilityHint();
            }
        } , SCREEN_ON_RING_HINT_DELAY);
        mKeyguardWidgetPager.showInitialPageHints();
        if (mHideHintsRunnable != null) {
            mMainQueue.postDelayed(mHideHintsRunnable, SCREEN_ON_RING_HINT_DELAY);//改嘛，就在这里，SCREEN_ON_RING_HINT_DELAY　改为　０
        }
    }

看下实现的流程：

mKeyguardWidgetPager.hideOutlinesAndSidePages()//要去找这里.

frameworks/base/policy/src/com/android/internal/policy/impl/keyguard/KeyguardWidgetPager.java

    void hideOutlinesAndSidePages() {
        animateOutlinesAndSidePages(false);
    }
    void animateOutlinesAndSidePages(final boolean show) {
        animateOutlinesAndSidePages(show, -1);
    }

void animateOutlinesAndSidePages(final boolean show, int duration) {
        if (mChildrenOutlineFadeAnimation != null) {
            mChildrenOutlineFadeAnimation.cancel();
            mChildrenOutlineFadeAnimation = null;
        }
        int count = getChildCount();
        PropertyValuesHolder alpha;
        ArrayList<Animator> anims = new ArrayList<Animator>();

        if (duration == -1) {
            duration = show ? CHILDREN_OUTLINE_FADE_IN_DURATION :
                CHILDREN_OUTLINE_FADE_OUT_DURATION;
        }

        int curPage = getNextPage();
        for (int i = 0; i < count; i++) {
            float finalContentAlpha;
            if (show) {
                finalContentAlpha = getAlphaForPage(mScreenCenter, i, true);
            } else if (!show && i == curPage) {
                finalContentAlpha = 1f;
            } else {
                finalContentAlpha = 0f;
            }
            KeyguardWidgetFrame child = getWidgetPageAt(i);

            alpha = PropertyValuesHolder.ofFloat("contentAlpha", finalContentAlpha);
            ObjectAnimator a = ObjectAnimator.ofPropertyValuesHolder(child, alpha);
            anims.add(a);

            float finalOutlineAlpha = show ? getOutlineAlphaForPage(mScreenCenter, i, true) : 0f;
            child.fadeFrame(this, show, finalOutlineAlpha, duration);
        }

        mChildrenOutlineFadeAnimation = new AnimatorSet();
        mChildrenOutlineFadeAnimation.playTogether(anims);

        mChildrenOutlineFadeAnimation.setDuration(duration);
        mChildrenOutlineFadeAnimation.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationStart(Animator animation) {
                if (show) {
                    enablePageContentLayers();
                }
            }

            @Override
            public void onAnimationEnd(Animator animation) {
                if (!show) {
                    disablePageContentLayers();
                    KeyguardWidgetFrame frame = getWidgetPageAt(mWidgetToResetAfterFadeOut);
                    if (frame != null && !(frame == getWidgetPageAt(mCurrentPage) &&
                            mViewStateManager.isChallengeOverlapping())) {
                        frame.resetSize();
                    }
                    mWidgetToResetAfterFadeOut = -1;
                    mShowingInitialHints = false;
                }
                updateWidgetFramesImportantForAccessibility();
            }
        });
        mChildrenOutlineFadeAnimation.start();
    }

没什么特别的，就是改了下显示的时间，把延迟改为０。

是功能是BUG，大家一看就明了。