将fitsSystemWindows设置为true时，CollapsingToolbarLayout内部的ViewGroup会显示额外的底部填充

// 获取系统窗口的尺寸
int statusBarHeight = getStatusBarHeight(this);
int navigationBarHeight = getNavigationBarHeight(this);

// 调整 CollapsingToolbarLayout 内部的填充
ViewGroup.LayoutParams params = collapsingToolbarLayout.getLayoutParams();
params.bottomMargin = navigationBarHeight;
collapsingToolbarLayout.setLayoutParams(params);

// 辅助方法：获取状态栏高度
public static int getStatusBarHeight(Context context) {
    int result = 0;
    int resourceId = context.getResources().getIdentifier("status_bar_height", "dimen", "android");
    if (resourceId > 0) {
        result = context.getResources().getDimensionPixelSize(resourceId);
    }
    return result;
}

// 辅助方法：获取导航栏高度（注意：此方法可能不适用于所有设备）
public static int getNavigationBarHeight(Context context) {
    int result = 0;
    if (hasNavBar(context)) {
        Resources res = context.getResources();
        int resourceId = res.getIdentifier("navigation_bar_height", "dimen", "android");
        if (resourceId > 0) {
            result = res.getDimensionPixelSize(resourceId);
        }
    }
    return result;
}

// 辅助方法：检查设备是否有导航栏
public static boolean hasNavBar(Context context) {
    boolean hasNavBar = false;
    Resources rs = context.getResources();
    int id = rs.getIdentifier("config_showNavigationBar", "bool", "android");
    if (id != 0) {
        hasNavBar = rs.getBoolean(id);
    }
    try {
        Class<?> systemPropertiesClass = Class.forName("android.os.SystemProperties");
        Method m = systemPropertiesClass.getMethod("get", String.class);
        String navBarOverride = (String) m.invoke(systemPropertiesClass, "qemu.hw.mainkeys");
        if ("1".equals(navBarOverride)) {
            hasNavBar = false;
        } else if ("0".equals(navBarOverride)) {
            hasNavBar = true;
        }
    } catch (Exception e) {
        // 忽略异常
    }
    return hasNavBar;
}