一. 狀態(tài)欄交互邏輯

1.FlutterActivity默認(rèn)設(shè)置

FlutterActivity初始化配置狀態(tài)欄腺兴。

FlutterActivity-onCreate()-configureStatusBarForFullscreenFlutterExperience()

     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
       Window window = getWindow();
       window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
       window.setStatusBarColor(0x40000000);
       window.getDecorView().setSystemUiVisibility(PlatformPlugin.DEFAULT_SYSTEM_UI);
     }

Android版本大于等于Android5.0（API-21）坡垫，默認(rèn)設(shè)置狀態(tài)欄陰影。

2.Flutter設(shè)置狀態(tài)欄

SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle style);

   static void setSystemUIOverlayStyle(SystemUiOverlayStyle style) {
     //上次設(shè)置的style任務(wù)完成阴汇，不允許加入新的任務(wù)，只是修改style的值
     if (_pendingStyle != null) {
       _pendingStyle = style;
       return;
     }
     //防止重復(fù)設(shè)置节槐，PageA-設(shè)置light成功搀庶，PageB-設(shè)置light不執(zhí)行
     if (style == _latestStyle) {
       return;
     }
     _pendingStyle = style;
     scheduleMicrotask(() {
       if (_pendingStyle != _latestStyle) {
         //將style轉(zhuǎn)成map，調(diào)用原生設(shè)置style
         SystemChannels.platform.invokeMethod<void>(
           'SystemChrome.setSystemUIOverlayStyle',
           _pendingStyle!._toMap(),
         );
         //記錄上次設(shè)置的style
         _latestStyle = _pendingStyle;
       }
       _pendingStyle = null;
     });
   }

3.Android設(shè)置Style

   //FlutterActivity
   @Override
   protected void onCreate(@Nullable Bundle savedInstanceState) {
     ...
     super.onCreate(savedInstanceState);
     
     //創(chuàng)建Delegate铜异，里面包含Plugin
     delegate = new FlutterActivityAndFragmentDelegate(this);
     delegate.onAttach(this);
     delegate.onRestoreInstanceState(savedInstanceState);
     ...
   }
   
   //FlutterActivityAndFragmentDelegate#onAttach(Context)
   void onAttach(@NonNull Context context) {
     ...
     //host為FlutterActivity
     platformPlugin = host.providePlatformPlugin(host.getActivity(), flutterEngine);
 
     host.configureFlutterEngine(flutterEngine);
   }
   
   //FlutterActivity
   public PlatformPlugin providePlatformPlugin(
       @Nullable Activity activity, @NonNull FlutterEngine flutterEngine) {
     return new PlatformPlugin(getActivity(), flutterEngine.getPlatformChannel(), this);
   }
   
   //PlatformPlugin構(gòu)造方法
   public PlatformPlugin(
       Activity activity, PlatformChannel platformChannel, PlatformPluginDelegate delegate) {
     this.activity = activity;
     this.platformChannel = platformChannel;
     //mPlatformMessageHandler負(fù)責(zé)處理Flutter傳遞的事件哥倔，中間省略部分賦值代碼~
     this.platformChannel.setPlatformMessageHandler(mPlatformMessageHandler);
     this.platformPluginDelegate = delegate;
 
     mEnabledOverlays = DEFAULT_SYSTEM_UI;
   }

mPlatformMessageHandler源碼

   final PlatformChannel.PlatformMessageHandler mPlatformMessageHandler =
       new PlatformChannel.PlatformMessageHandler() {
         @Override
         public void playSystemSound(@NonNull PlatformChannel.SoundType soundType) {
           PlatformPlugin.this.playSystemSound(soundType);
         }
 
         @Override
         public void vibrateHapticFeedback(
             @NonNull PlatformChannel.HapticFeedbackType feedbackType) {
           PlatformPlugin.this.vibrateHapticFeedback(feedbackType);
         }
 
         @Override
         public void setPreferredOrientations(int androidOrientation) {
           setSystemChromePreferredOrientations(androidOrientation);
         }
 
         @Override
         public void setApplicationSwitcherDescription(
             @NonNull PlatformChannel.AppSwitcherDescription description) {
           setSystemChromeApplicationSwitcherDescription(description);
         }
 
         @Override
         public void showSystemOverlays(@NonNull List<PlatformChannel.SystemUiOverlay> overlays) {
           setSystemChromeEnabledSystemUIOverlays(overlays);
         }
 
         @Override
         public void showSystemUiMode(@NonNull PlatformChannel.SystemUiMode mode) {
           setSystemChromeEnabledSystemUIMode(mode);
         }
 
         @Override
         public void setSystemUiChangeListener() {
           setSystemChromeChangeListener();
         }
 
         @Override
         public void restoreSystemUiOverlays() {
           restoreSystemChromeSystemUIOverlays();
         }
 
         //真實(shí)處理Flutter設(shè)置style的方法
         //SystemChannels.platform.invokeMethod<void>(
         //  'SystemChrome.setSystemUIOverlayStyle',
         //  _pendingStyle!._toMap(),
         // );
         @Override
         public void setSystemUiOverlayStyle(
             @NonNull PlatformChannel.SystemChromeStyle systemUiOverlayStyle) {
           setSystemChromeSystemUIOverlayStyle(systemUiOverlayStyle);
         }
 
         @Override
         public void popSystemNavigator() {
           PlatformPlugin.this.popSystemNavigator();
         }
 
         @Override
         public CharSequence getClipboardData(
             @Nullable PlatformChannel.ClipboardContentFormat format) {
           return PlatformPlugin.this.getClipboardData(format);
         }
 
         @Override
         public void setClipboardData(@NonNull String text) {
           PlatformPlugin.this.setClipboardData(text);
         }
 
         @Override
         public boolean clipboardHasStrings() {
           return PlatformPlugin.this.clipboardHasStrings();
         }
       };
 

setSystemChromeSystemUIOverlayStyle源碼如下，這塊就是純安卓代碼了揍庄。

   private void setSystemChromeSystemUIOverlayStyle(
       PlatformChannel.SystemChromeStyle systemChromeStyle) {
     Window window = activity.getWindow();
     View view = window.getDecorView();
     WindowInsetsControllerCompat windowInsetsControllerCompat =
         new WindowInsetsControllerCompat(window, view);
 
     // SYSTEM STATUS BAR -------------------------------------------------------------------
     // You can't change the color of the system status bar until SDK 21, and you can't change the
     // color of the status icons until SDK 23. We only allow both starting at 23 to ensure buttons
     // and icons can be visible when changing the background color.
     // If transparent, SDK 29 and higher may apply a translucent scrim behind the bar to ensure
     // proper contrast. This can be overridden with
     // SystemChromeStyle.systemStatusBarContrastEnforced.
     if (Build.VERSION.SDK_INT >= 23) {
       if (systemChromeStyle.statusBarIconBrightness != null) {
         switch (systemChromeStyle.statusBarIconBrightness) {
           case DARK:
             // Dark status bar icon brightness.
             // Light status bar appearance.
             windowInsetsControllerCompat.setAppearanceLightStatusBars(true);
             break;
           case LIGHT:
             // Light status bar icon brightness.
             // Dark status bar appearance.
             windowInsetsControllerCompat.setAppearanceLightStatusBars(false);
             break;
         }
       }
 
       if (systemChromeStyle.statusBarColor != null) {
         window.setStatusBarColor(systemChromeStyle.statusBarColor);
       }
     }
     // You can't override the enforced contrast for a transparent status bar until SDK 29.
     // This overrides the translucent scrim that may be placed behind the bar on SDK 29+ to ensure
     // contrast is appropriate when using full screen layout modes like Edge to Edge.
     if (systemChromeStyle.systemStatusBarContrastEnforced != null && Build.VERSION.SDK_INT >= 29) {
       window.setStatusBarContrastEnforced(systemChromeStyle.systemStatusBarContrastEnforced);
     }
 
     // SYSTEM NAVIGATION BAR --------------------------------------------------------------
     // You can't change the color of the system navigation bar until SDK 21, and you can't change
     // the color of the navigation buttons until SDK 26. We only allow both starting at 26 to
     // ensure buttons can be visible when changing the background color.
     // If transparent, SDK 29 and higher may apply a translucent scrim behind 2/3 button navigation
     // bars to ensure proper contrast. This can be overridden with
     // SystemChromeStyle.systemNavigationBarContrastEnforced.
     if (Build.VERSION.SDK_INT >= 26) {
       if (systemChromeStyle.systemNavigationBarIconBrightness != null) {
         switch (systemChromeStyle.systemNavigationBarIconBrightness) {
           case DARK:
             // Dark navigation bar icon brightness.
             // Light navigation bar appearance.
             windowInsetsControllerCompat.setAppearanceLightNavigationBars(true);
             break;
           case LIGHT:
             // Light navigation bar icon brightness.
             // Dark navigation bar appearance.
             windowInsetsControllerCompat.setAppearanceLightNavigationBars(false);
             break;
         }
       }
 
       if (systemChromeStyle.systemNavigationBarColor != null) {
         window.setNavigationBarColor(systemChromeStyle.systemNavigationBarColor);
       }
     }
     // You can't change the color of the navigation bar divider color until SDK 28.
     if (systemChromeStyle.systemNavigationBarDividerColor != null && Build.VERSION.SDK_INT >= 28) {
       window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
       window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
       window.setNavigationBarDividerColor(systemChromeStyle.systemNavigationBarDividerColor);
     }
 
     // You can't override the enforced contrast for a transparent navigation bar until SDK 29.
     // This overrides the translucent scrim that may be placed behind 2/3 button navigation bars on
     // SDK 29+ to ensure contrast is appropriate when using full screen layout modes like
     // Edge to Edge.
     if (systemChromeStyle.systemNavigationBarContrastEnforced != null
         && Build.VERSION.SDK_INT >= 29) {
       window.setNavigationBarContrastEnforced(
           systemChromeStyle.systemNavigationBarContrastEnforced);
     }
 
     currentTheme = systemChromeStyle;
   }

4. 混合開發(fā)帶來的問題

如果是混合開發(fā)咆蒿，調(diào)用棧如下：Navtive-Flutter，FlutterActivity關(guān)閉后蚂子，再次打開FlutterActivity沃测，在Flutter設(shè)置狀態(tài)欄不生效。

Flutter可使用SystemChrome.restoreSystemUIOverlays();食茎，恢復(fù)最后一次設(shè)置的Style蒂破，源碼如下：

   static Future<void> restoreSystemUIOverlays() async {
     await SystemChannels.platform.invokeMethod<void>(
       'SystemChrome.restoreSystemUIOverlays',
       null,
     );
   }

Android可在FlutterActivity中調(diào)用updateSystemUiOverlays()恢復(fù)最后一次設(shè)置的Style。源碼如下：

  //FlutterActivity 
  @Override
   public void updateSystemUiOverlays() {
     if (delegate != null) {
       delegate.updateSystemUiOverlays();
     }
   }
   
   //FlutterActivityAndFragmentDelegate
   void updateSystemUiOverlays() {
     if (platformPlugin != null) {
       // TODO(mattcarroll): find a better way to handle the update of UI overlays than calling
       // through to platformPlugin. We're implicitly entangling the Window, Activity,
       // Fragment, and engine all with this one call.
       platformPlugin.updateSystemUiOverlays();
     }
   }
   
   //PlatformPlugin
   public void updateSystemUiOverlays() {
     activity.getWindow().getDecorView().setSystemUiVisibility(mEnabledOverlays);
     //上次設(shè)置的style
     if (currentTheme != null) {
       setSystemChromeSystemUIOverlayStyle(currentTheme);
     }
   }

二.Flutter不同頁面設(shè)置不同Style實(shí)現(xiàn)

假如有如下邏輯：不同頁面的狀態(tài)欄配置不同别渔。

PageA(light)-PageB(dark)

打開PageA設(shè)置狀態(tài)欄白色圖標(biāo)附迷，打開PageB設(shè)置狀態(tài)欄黑色圖標(biāo)，返回到PageA再次設(shè)置狀態(tài)欄白色圖標(biāo)哎媚。

通過監(jiān)聽Flutter頁面變化實(shí)現(xiàn)喇伯，需要使用命名路由：繼承NavigatorObserver，代碼如下：

 void main() {
   runApp(MaterialApp(
       ...
       routes: {
         "/A": (context) => PageA(),
         "/B": (context) => PageB(),
       },
       navigatorObservers: [RouteObserver()],
   ));
 }
 
 class RouteObserver extends NavigatorObserver {
 
   final Map<String, SystemUiOverlayStyle> _map = {};
 
   RouteObserver() {
     _map["/"] = dark;
     _map["/A"] = light;
     _map["/B"] = dark;
   }
 
   ///設(shè)置亮色狀態(tài)欄和導(dǎo)航欄
   ///android 默認(rèn)statusBarColor = Color(0x40000000)拨与，只對安卓生[L]及以上生效
   final SystemUiOverlayStyle light =
       SystemUiOverlayStyle.light.copyWith(statusBarColor: Colors.transparent);
 
   ///設(shè)置暗色狀態(tài)欄和導(dǎo)航欄
   ///android 默認(rèn)statusBarColor = Color(0x40000000)艘刚，只對安卓生[L]及以上生效
   final SystemUiOverlayStyle dark =
       SystemUiOverlayStyle.dark.copyWith(statusBarColor: Colors.transparent);
 
   @override
   void didPop(Route route, Route? previousRoute) {
     _setSystemUIOverlayStyle(previousRoute, route);
   }
 
   @override
   void didPush(Route route, Route? previousRoute) {
     _setSystemUIOverlayStyle(route, previousRoute);
   }
 
   @override
   void didReplace({Route? newRoute, Route? oldRoute}) {
     _setSystemUIOverlayStyle(newRoute, oldRoute);
   }
 
   void _setSystemUIOverlayStyle(Route? toRoute, Route? formRoute) {
     String? toName = _getRoutNameFromRoute(toRoute);
     String? formName = _getRoutNameFromRoute(formRoute);
     if (toName == null) {
       return;
     }
     SystemUiOverlayStyle? toStyle = _map[toName];
     SystemUiOverlayStyle? fromStyle = _map[formName];
     if (toStyle != null && toStyle != fromStyle) {
       //這里沒有調(diào)用Flutter自帶的方法是為了解決混合開發(fā)帶來的問題
       SystemChannels.platform.invokeMethod<void>(
         'SystemChrome.setSystemUIOverlayStyle',
         _style2Map(toStyle),
       );
     }
   }
 
   Map<String, dynamic> _style2Map(SystemUiOverlayStyle style) {
     return <String, dynamic>{
       'systemNavigationBarColor': style.systemNavigationBarColor?.value,
       'systemNavigationBarDividerColor':
           style.systemNavigationBarDividerColor?.value,
       'systemStatusBarContrastEnforced': style.systemStatusBarContrastEnforced,
       'statusBarColor': style.statusBarColor?.value,
       'statusBarBrightness': style.statusBarBrightness?.toString(),
       'statusBarIconBrightness': style.statusBarIconBrightness?.toString(),
       'systemNavigationBarIconBrightness':
           style.systemNavigationBarIconBrightness?.toString(),
       'systemNavigationBarContrastEnforced':
           style.systemNavigationBarContrastEnforced,
     };
     SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.light);
     SystemChrome.restoreSystemUIOverlays();
   }
 
   String? _getRoutNameFromRoute(Route? route) {
     if (route == null) {
       return null;
     }
     RouteSettings routeSettings = route.settings;
     return routeSettings.name;
   }
 }

源代碼見GitHub