1. 原生设置沉浸式状态栏：

(1) 在底层activity中设置：

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            // Android 5.0 以上 全透明
            Window window = getWindow();
            window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS
                    | WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
            window.getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                    | View.SYSTEM_UI_FLAG_LAYOUT_STABLE);
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            // 状态栏（以上几行代码必须，参考setStatusBarColor|setNavigationBarColor方法源码）
            window.setStatusBarColor(Color.TRANSPARENT);
            // 虚拟导航键
            window.setNavigationBarColor(0xfff0f0f0);
        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            // Android 4.4 以上 半透明
            Window window = getWindow();
            // 状态栏
            window.addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            // 虚拟导航键
          window.addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
        }

(2) 设置闪屏页全面屏隐藏状态栏和虚拟按键

//取消状态栏
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
        WindowManager.LayoutParams.FLAG_FULLSCREEN);

//一定得在setContentView()上面

//隐藏虚拟按键：
protected void hideBottomUIMenu() {
    //隐藏虚拟按键，并且全屏
    if (Build.VERSION.SDK_INT > 11 && Build.VERSION.SDK_INT < 19) { // lower api
        View v = this.getWindow().getDecorView();
        v.setSystemUiVisibility(View.GONE);
    } else if (Build.VERSION.SDK_INT >= 19) {
        //for new api versions.
        View decorView = getWindow().getDecorView();
        int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY | View.SYSTEM_UI_FLAG_FULLSCREEN;
        decorView.setSystemUiVisibility(uiOptions);
    }
}
//这个也可以：
public void hideNavigationBar() {
        int uiFlags = View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar
                | View.SYSTEM_UI_FLAG_FULLSCREEN; // hide status bar

        if (android.os.Build.VERSION.SDK_INT >= 19) {
            uiFlags |= View.SYSTEM_UI_FLAG_IMMERSIVE;//0x00001000; // SYSTEM_UI_FLAG_IMMERSIVE_STICKY: hide
        } else {
            uiFlags |= View.SYSTEM_UI_FLAG_LOW_PROFILE;
        }

        try {
            getWindow().getDecorView().setSystemUiVisibility(uiFlags);
        } catch (Exception e) {
            // TODO: handle exception
        }

}

(3) flutter中设置：

3.1在main.dart， build前中设置：

SystemUiOverlayStyle systemUiOverlayStyle =
      SystemUiOverlayStyle(
        statusBarColor: Colors.transparent,//状态栏
        systemNavigationBarColor:Color(0xfff0f0f0),//虚拟按键背景色
        systemNavigationBarDividerColor: Colors.transparent,
        systemNavigationBarIconBrightness: Brightness.dark,//虚拟按键图标色
        statusBarIconBrightness: Brightness.light,
        statusBarBrightness: Brightness.light,
      );
      SystemChrome.setSystemUIOverlayStyle(systemUiOverlayStyle);

3.2若界面有AppBar

可以直接在AppBar中的 brightness设置状态栏字体颜色，值如下

Brightness.light：黑色
Brightness.dark: 白色

AppBar中的brightness值若不设置，改值会默认取全局的theme中设置primaryColorBrightness的值，

3.3若界面没有AppBar

则同在main.dart中设置一样在build中设置，（但是会有问题），该界面状态栏字体颜色会在进入下一个页面后回退时，保持上个页面的状态栏样颜色。所以建议可以设置一个没有高度的AppBar，这样就可以随意设置状态栏字体颜色：没高度的AppBar如下：

PreferredSize(
            child: AppBar(
              backgroundColor: Colors.white,
              elevation: 0,//appBar底部线去除
            ),
            preferredSize: Size.fromHeight(0))

但是使用AppBar若界面是图片置顶的，则不能做到沉浸式。所以使用3.3的方式（暂时没有找到更好的方法）

(4)在flutter中使用flutter_boost

需要在native端设置相应通过flutter_boost跳转的页面，flutter的页面也需要单独设置。

4 配上兼容部分机型的代码

使用

//状态栏
 StatusBarUtils.setLightStatusBar(this,true);
//虚拟按键背景
 StatusBarUtils.setStatusBarColor(this, 0xff666666);

package com.paff.myapplication.utils;

import android.annotation.TargetApi;
import android.app.Activity;
import android.graphics.Color;
import android.os.Build;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;

import com.readystatesoftware.systembartint.SystemBarTintManager;

import java.lang.reflect.Field;
import java.lang.reflect.Method;

public class StatusBarUtils {
    @TargetApi(19)
    public static void transparencyBar(Activity activity) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            Window window = activity.getWindow();
            window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            window.setStatusBarColor(Color.TRANSPARENT);
            window.getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                    | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);

        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            Window window = activity.getWindow();
            window.setFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS,
                    WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
        }
    }

    /**
     * 修改状态栏颜色，支持4.4以上版本
     *
     * @param activity
     * @param color
     */
    public static void setStatusBarColor(Activity activity , int color) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            Window window = activity.getWindow();
            window.getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                    | View.SYSTEM_UI_FLAG_LAYOUT_STABLE);
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            // 状态栏（以上几行代码必须，参考setStatusBarColor|setNavigationBarColor方法源码）
            window.setStatusBarColor(Color.TRANSPARENT);
            // 虚拟导航键
            window.setNavigationBarColor(color);
        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            //使用SystemBarTint库使4.4版本状态栏变色，需要先将状态栏设置为透明
            transparencyBar(activity);
            SystemBarTintManager tintManager = new SystemBarTintManager(activity);
            tintManager.setStatusBarTintEnabled(true);
            tintManager.setStatusBarTintResource(Color.TRANSPARENT);
        }
    }

    /**
     *  修改状态栏文字颜色，这里小米，魅族区别对待。
     */
    public static void setLightStatusBar(final Activity activity, final boolean dark) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            switch (RomUtils.getLightStatusBarAvailableRomType()) {
                case RomUtils.AvailableRomType.MIUI:
                    MIUISetStatusBarLightMode(activity, dark);
                    break;

                case RomUtils.AvailableRomType.FLYME:
                    setFlymeLightStatusBar(activity, dark);

                    break;

                case RomUtils.AvailableRomType.ANDROID_NATIVE:
                    setAndroidNativeLightStatusBar(activity, dark);
                    break;

            }
        }
    }


    public static boolean MIUISetStatusBarLightMode(Activity activity, boolean dark) {
        boolean result = false;
        Window window = activity.getWindow();
        if (window != null) {
            Class clazz = window.getClass();
            try {
                int darkModeFlag = 0;
                Class layoutParams = Class.forName("android.view.MiuiWindowManager$LayoutParams");
                Field field = layoutParams.getField("EXTRA_FLAG_STATUS_BAR_DARK_MODE");
                darkModeFlag = field.getInt(layoutParams);
                Method extraFlagField = clazz.getMethod("setExtraFlags", int.class, int.class);
                if (dark) {
                    extraFlagField.invoke(window, darkModeFlag, darkModeFlag);//状态栏透明且黑色字体
                } else {
                    extraFlagField.invoke(window, 0, darkModeFlag);//清除黑色字体
                }
                result = true;

                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && RomUtils.isMiUIV7OrAbove()) {
                    //开发版 7.7.13 及以后版本采用了系统API，旧方法无效但不会报错，所以两个方式都要加上
                    if (dark) {
                        activity.getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);
                    } else {
                        activity.getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_LAYOUT_STABLE);
                    }
                }
            } catch (Exception e) {

            }
        }
        return result;
    }

    private static boolean setFlymeLightStatusBar(Activity activity, boolean dark) {
        boolean result = false;
        if (activity != null) {
            try {
                WindowManager.LayoutParams lp = activity.getWindow().getAttributes();
                Field darkFlag = WindowManager.LayoutParams.class
                        .getDeclaredField("MEIZU_FLAG_DARK_STATUS_BAR_ICON");
                Field meizuFlags = WindowManager.LayoutParams.class
                        .getDeclaredField("meizuFlags");
                darkFlag.setAccessible(true);
                meizuFlags.setAccessible(true);
                int bit = darkFlag.getInt(null);
                int value = meizuFlags.getInt(lp);
                if (dark) {
                    value |= bit;
                } else {
                    value &= ~bit;
                }
                meizuFlags.setInt(lp, value);
                activity.getWindow().setAttributes(lp);
                result = true;
            } catch (Exception e) {
            }
        }
        return result;
    }

    private static void setAndroidNativeLightStatusBar(Activity activity, boolean dark) {
        View decor = activity.getWindow().getDecorView();
        if (dark) {
            decor.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);
        } else {
            decor.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_LAYOUT_STABLE);
        }
    }

    //隐藏虚拟按键：
    public static void hideBottomUIMenu(Activity activity) {
        //隐藏虚拟按键，并且全屏
       /* activity.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);*/
        if (Build.VERSION.SDK_INT > 11 && Build.VERSION.SDK_INT < 19) { // lower api
            View v = activity.getWindow().getDecorView();
            v.setSystemUiVisibility(View.GONE);
        } else if (Build.VERSION.SDK_INT >= 19) {
            //for new api versions.
            View decorView =activity.getWindow().getDecorView();
            int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                    | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY | View.SYSTEM_UI_FLAG_FULLSCREEN;
            decorView.setSystemUiVisibility(uiOptions);
        }
    }
    //这个也可以：
    public static void hideNavigationBar(Activity activity) {
        int uiFlags = View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar
                | View.SYSTEM_UI_FLAG_FULLSCREEN; // hide status bar

        if (android.os.Build.VERSION.SDK_INT >= 19) {
            uiFlags |= View.SYSTEM_UI_FLAG_IMMERSIVE;//0x00001000; // SYSTEM_UI_FLAG_IMMERSIVE_STICKY: hide
        } else {
            uiFlags |= View.SYSTEM_UI_FLAG_LOW_PROFILE;
        }

        try {
            activity.getWindow().getDecorView().setSystemUiVisibility(uiFlags);
        } catch (Exception e) {
            // TODO: handle exception
        }

    }
}

package com.paff.myapplication.utils;

import android.os.Build;
import android.os.Environment;
import android.text.TextUtils;

import java.io.File;
import java.io.FileInputStream;
import java.util.Properties;

public class RomUtils {
    class AvailableRomType {
        public static final int MIUI = 1;
        public static final int FLYME = 2;
        public static final int ANDROID_NATIVE = 3;
        public static final int NA = 4;
    }

    public static int getLightStatusBarAvailableRomType() {
        //开发版 7.7.13 及以后版本采用了系统API，旧方法无效但不会报错
        if (isMiUIV7OrAbove()) {
            return AvailableRomType.ANDROID_NATIVE;
        }

        if (isMiUIV6OrAbove()) {
            return AvailableRomType.MIUI;
        }

        if (isFlymeV4OrAbove()) {
            return AvailableRomType.FLYME;
        }

        if (isAndroidMOrAbove()) {
            return AvailableRomType.ANDROID_NATIVE;
        }

        return AvailableRomType.NA;
    }

    //Flyme V4的displayId格式为 [Flyme OS 4.x.x.xA]
    //Flyme V5的displayId格式为 [Flyme 5.x.x.x beta]
    private static boolean isFlymeV4OrAbove() {
        String displayId = Build.DISPLAY;
        if (!TextUtils.isEmpty(displayId) && displayId.contains("Flyme")) {
            String[] displayIdArray = displayId.split(" ");
            for (String temp : displayIdArray) {
                //版本号4以上，形如4.x.
                if (temp.matches("^[4-9]\\.(\\d+\\.)+\\S*")) {
                    return true;
                }
            }
        }
        return false;
    }

    //Android Api 23以上
    private static boolean isAndroidMOrAbove() {
        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.M;
    }

    private static final String KEY_MIUI_VERSION_CODE = "ro.miui.ui.version.code";

    private static boolean isMiUIV6OrAbove() {
        try {
            final Properties properties = new Properties();
            properties.load(new FileInputStream(new File(Environment.getRootDirectory(), "build.prop")));
            String uiCode = properties.getProperty(KEY_MIUI_VERSION_CODE, null);
            if (uiCode != null) {
                int code = Integer.parseInt(uiCode);
                return code >= 4;
            } else {
                return false;
            }

        } catch (final Exception e) {
            return false;
        }

    }

    static boolean isMiUIV7OrAbove() {
        try {
            final Properties properties = new Properties();
            properties.load(new FileInputStream(new File(Environment.getRootDirectory(), "build.prop")));
            String uiCode = properties.getProperty(KEY_MIUI_VERSION_CODE, null);
            if (uiCode != null) {
                int code = Integer.parseInt(uiCode);
                return code >= 5;
            } else {
                return false;
            }

        } catch (final Exception e) {
            return false;
        }

    }

}

Android（flutter）状态栏，虚拟按键处理