一、問題描述

由于我們的項(xiàng)目是手機(jī)桌面的負(fù)一屏，沒有Activity而是通過Window.addView實(shí)現(xiàn)的。
所以無法直接使用常規(guī)的設(shè)置狀態(tài)欄的方式修改顏色。
最后通過分析原理，給View設(shè)置標(biāo)志位，結(jié)果還有問題，就有了這一篇文章了。

二、排查流程

一圖勝千言

狀態(tài)欄顏色修改不生效問題流程排查.png

1. 場(chǎng)景
   沉浸式，一個(gè)動(dòng)畫滾動(dòng)的場(chǎng)景下需要吸頂，然后對(duì)應(yīng)的狀態(tài)欄文字需要跟著變換顏色。
2. 情況特殊
   由于沒有Activity的存在，無法直接調(diào)用Activity的方法實(shí)現(xiàn)修改狀態(tài)欄
3. 分析狀態(tài)欄修改原理 參考
   其實(shí)就是給view設(shè)置標(biāo)志位，與Activity并沒有關(guān)系
4. 分析誰調(diào)用了這個(gè)標(biāo)識(shí) Appearance_Light_Status_Bars
   找到了是DisplayPolicy
5. 通過dump逐一排查當(dāng)前狀態(tài)
   5.1. 肯定是appWindow，因?yàn)橛玫木褪荳indowManager.LayoutParams.TYPE_APPLICATION
   5.2. attached應(yīng)該為null,因?yàn)椴皇莝ubWindow
   5.3. 發(fā)現(xiàn)少了FullScreen標(biāo)識(shí)，一般正常的Activity都有這個(gè)標(biāo)識(shí)。但我們是負(fù)一屏，沒有Activity，是通過window添加的，那么這個(gè)添加的參數(shù)是否有問題。
6. 查詢isFullScreen方法的判斷標(biāo)準(zhǔn)
   果然問題就在這里，我們?cè)仍O(shè)置的寬高直接讀取了屏幕高寬，并非設(shè)置的MatchParent

三、相應(yīng)的源碼

DisplayPolicy

    /**
     * Called following layout of all window to apply policy to each window.
     *
     * @param win The window being positioned.
     * @param attrs The LayoutParams of the window.
     * @param attached For sub-windows, the window it is attached to. Otherwise null.
     */
    public void applyPostLayoutPolicyLw(WindowState win, WindowManager.LayoutParams attrs,
            WindowState attached, WindowState imeTarget) {
    //省略若干...
        boolean appWindow = attrs.type >= FIRST_APPLICATION_WINDOW
                && attrs.type < FIRST_SYSTEM_WINDOW;
    //省略若干...
        // Check the windows that overlap with system bars to determine system bars' appearance.
        if ((appWindow && attached == null && attrs.isFullscreen())
                || attrs.type == TYPE_VOICE_INTERACTION) {
                //省略若干...
            // Cache app windows that is overlapping with the status bar to determine appearance
            // of status bar.
            if (mStatusBar != null
                    && sTmpRect.setIntersect(win.getFrame(), mStatusBar.getFrame())
                    && !mStatusBarBackgroundCheckedBounds.contains(sTmpRect)) {
                mStatusBarBackgroundWindows.add(win);
                mStatusBarBackgroundCheckedBounds.union(sTmpRect);
                if (!mStatusBarColorCheckedBounds.contains(sTmpRect)) {
                    mStatusBarAppearanceRegionList.add(new AppearanceRegion(
                            win.mAttrs.insetsFlags.appearance & APPEARANCE_LIGHT_STATUS_BARS,
                            new Rect(win.getFrame())));
                    mStatusBarColorCheckedBounds.union(sTmpRect);
                }
            }
        }
    //省略若干...
}

WindowManager.LayoutParams

        /**
         * @hide
         * @return True if the layout parameters will cause the window to cover the full screen;
         *         false otherwise.
         */
        public boolean isFullscreen() {
            return x == 0 && y == 0
                    && width == WindowManager.LayoutParams.MATCH_PARENT
                    && height == WindowManager.LayoutParams.MATCH_PARENT;
        }