StatusBarUtil 工具类

package android.car.ui;

import android.annotation.TargetApi;
import android.app.Activity;
import android.car.ui.util.ColorUtils;
import android.content.Context;
import android.graphics.Color;
import android.os.Build;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.widget.LinearLayout;

public class StatusBarUtil {

    /** 设置状态栏背景，根据背景来调整字体颜色 */
    public static void adaptStatusByBgColor(Window window, int statusBgColor) {
        if (Build.VERSION.SDK_INT >= 21) {
            // 设置状态栏背景
            int flag = WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS;
            if ((window.getAttributes().flags & flag) == 0) {
                window.addFlags(flag);
            }
            window.setStatusBarColor(statusBgColor);

            // 设置状态栏字体颜色（黑|白）
            View decor = window.getDecorView();
            int visibility = decor.getSystemUiVisibility();
            if (Build.VERSION.SDK_INT >= 23) {
                boolean lightStatusBgColor = ColorUtils.isLightColor(statusBgColor);
                visibility = (visibility & ~View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR)
                        | (lightStatusBgColor ? View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR : 0);
            }
            decor.setSystemUiVisibility(visibility);
        }
    }

    /** 将布局显示到状态栏（底层） */
    public static void setLayoutUnderStatus(View decorView, boolean layoutUnderStatus) {
        int visibility = decorView.getSystemUiVisibility();
        if (layoutUnderStatus) {
            visibility |= View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                    | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN;
        } else {
            visibility &= ~View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN;
        }
        decorView.setSystemUiVisibility(visibility);
    }

    /**
     * 设置状态栏颜色
     *
     * @param activity       需要设置的activity
     * @param color          状态栏颜色值
     * @param statusBarAlpha 状态栏透明度
     */
    public static void setColor(Activity activity, int color, int statusBarAlpha, int fakeStatusBarId) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            activity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            activity.getWindow().setStatusBarColor(calculateStatusColor(color, statusBarAlpha));
        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            ViewGroup decorView = (ViewGroup) activity.getWindow().getDecorView();
            View fakeStatusBarView = decorView.findViewById(fakeStatusBarId);
            if (fakeStatusBarView != null) {
                if (fakeStatusBarView.getVisibility() == View.GONE) {
                    fakeStatusBarView.setVisibility(View.VISIBLE);
                }
                fakeStatusBarView.setBackgroundColor(calculateStatusColor(color, statusBarAlpha));
            } else {
                decorView.addView(createStatusBarView(activity, color, statusBarAlpha, fakeStatusBarId));
            }
            setRootView(activity);
        }
    }

    /**
     * 使状态栏透明
     */
    @TargetApi(Build.VERSION_CODES.KITKAT)
    private static void transparentStatusBar(Activity activity) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            activity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
            activity.getWindow().setStatusBarColor(Color.TRANSPARENT);
        } else {
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
        }
    }

    /**
     * 生成一个和状态栏大小相同的半透明矩形条
     *
     * @param activity 需要设置的activity
     * @param color    状态栏颜色值
     * @param alpha    透明值
     * @return 状态栏矩形条
     */
    private static View createStatusBarView(Activity activity, int color, int alpha, int fakeStatusBarId) {
        // 绘制一个和状态栏一样高的矩形
        View statusBarView = new View(activity);
        LinearLayout.LayoutParams params =
                new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, getStatusBarHeight(activity));
        statusBarView.setLayoutParams(params);
        statusBarView.setBackgroundColor(calculateStatusColor(color, alpha));
        statusBarView.setId(fakeStatusBarId);
        return statusBarView;
    }

    /**
     * 设置根布局参数
     */
    private static void setRootView(Activity activity) {
        ViewGroup parent = activity.findViewById(android.R.id.content);
        for (int i = 0, count = parent.getChildCount(); i < count; i++) {
            View childView = parent.getChildAt(i);
            if (childView instanceof ViewGroup) {
                childView.setFitsSystemWindows(true);
                ((ViewGroup) childView).setClipToPadding(true);
            }
        }
    }

    /**
     * 获取状态栏高度
     *
     * @param context context
     * @return 状态栏高度
     */
    public static int getStatusBarHeight(Context context) {
        // 获得状态栏高度
        int resourceId = context.getResources().getIdentifier("status_bar_height", "dimen", "android");
        return context.getResources().getDimensionPixelSize(resourceId);
    }

    /**
     * 计算状态栏颜色
     *
     * @param color color值
     * @param alpha alpha值
     * @return 最终的状态栏颜色
     */
    private static int calculateStatusColor(int color, int alpha) {
        if (alpha == 0) {
            return color;
        }
        float a = 1 - alpha / 255f;
        int red = color >> 16 & 0xff;
        int green = color >> 8 & 0xff;
        int blue = color & 0xff;
        red = (int) (red * a + 0.5);
        green = (int) (green * a + 0.5);
        blue = (int) (blue * a + 0.5);
        return 0xff << 24 | red << 16 | green << 8 | blue;
    }

}