数据库定义了一个字段叫 allow,

4 读2 写 1 执行 如果是 7 就代表是可读可写 可执行 ，如果是5 就是可读 可执行 ， 那具体代码咋写呢

[Flags]
public enum Permission
{
    None = 0,
    Execute = 1,
    Write = 2,
    Read = 4
}

// 假设你从数据库取到的 allow 值是一个整数
int allow = 5; // 代表 读+执行

bool canRead = (allow & (int)Permission.Read) != 0;
bool canWrite = (allow & (int)Permission.Write) != 0;
bool canExecute = (allow & (int)Permission.Execute) != 0;
Console.WriteLine($"Read: {canRead}, Write: {canWrite}, Execute: {canExecute}");

数据库的判断实现

SELECT
    id,
    allow,
    CASE WHEN (allow & 4) != 0 THEN '是' ELSE '否' END AS 可读,
    CASE WHEN (allow & 2) != 0 THEN '是' ELSE '否' END AS 可写,
    CASE WHEN (allow & 1) != 0 THEN '是' ELSE '否' END AS 可执行
FROM your_table;

举一反三
我们也可以在代码中这样表示

下面就代表我定义了一个可读可写的，

int allow = Permission.READ | Permission.WRITE; // 4 | 2 = 6(二进制 110)

判断

boolean canRead = (allow & Permission.READ) != 0;
boolean canWrite = (allow & Permission.WRITE) != 0;
boolean canExecute = (allow & Permission.EXECUTE) != 0;

完整案例

public class Permission {
    public static final int EXECUTE = 1; // 001
    public static final int WRITE = 2;   // 010
    public static final int READ = 4;    // 100

    public static void main(String[] args) {
        int allow = READ | WRITE; // 4 | 2 = 6

        System.out.println("Can Read: " + ((allow & READ) != 0));
        System.out.println("Can Write: " + ((allow & WRITE) != 0));
        System.out.println("Can Execute: " + ((allow & EXECUTE) != 0));
    }
}

ok
然后来到了安卓的伪代码

public class View {
    // 定义系统 UI 的标志位
    public static final int SYSTEM_UI_FLAG_VISIBLE            = 0x00000000; // 默认可见
    public static final int SYSTEM_UI_FLAG_FULLSCREEN         = 0x00000004; // 隐藏状态栏
    public static final int SYSTEM_UI_FLAG_HIDE_NAVIGATION    = 0x00000002; // 隐藏导航栏
    public static final int SYSTEM_UI_FLAG_IMMERSIVE_STICKY   = 0x00001000; // 沉浸式模式

    private int systemUiVisibility = SYSTEM_UI_FLAG_VISIBLE;

    public void setSystemUiVisibility(int flags) {
        systemUiVisibility = flags;
        System.out.println("已设置 UI flags = " + Integer.toBinaryString(flags));
    }

    public int getSystemUiVisibility() {
        return systemUiVisibility;
    }
}

public class Activity {
    private View decorView = new View();

    public void onCreate() {
        // 组合多个 UI flags：全屏 + 隐藏导航栏 + 沉浸模式
        int flags = View.SYSTEM_UI_FLAG_FULLSCREEN
                  | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                  | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;

        decorView.setSystemUiVisibility(flags);

        // 检查是否设置了全屏
        if ((decorView.getSystemUiVisibility() & View.SYSTEM_UI_FLAG_FULLSCREEN) != 0) {
            System.out.println("✅ 全屏模式已开启");
        }
    }
}

ok再来复习一下安卓的常见代码

Intent intent = new Intent(context, MyActivity.class);

// 添加多个 flag
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);

// 判断是否包含某个 flag
if ((intent.getFlags() & Intent.FLAG_ACTIVITY_NEW_TASK) != 0) {
    Log.d("Intent", "是 NEW_TASK 启动模式");
}

Paint paint = new Paint();

// 开启抗锯齿、滤波、描边
paint.setFlags(Paint.ANTI_ALIAS_FLAG 
             | Paint.FILTER_BITMAP_FLAG 
             | Paint.DITHER_FLAG);

c#

[Flags]
public enum Permission
{
    None   = 0,
    Query  = 1,  // 0001
    Add    = 2,  // 0010
    Edit   = 4,  // 0100
    Delete = 8   // 1000
}

使用示例

class Program
{
    static void Main()
    {
        // 组合权限：查询 + 编辑
        Permission userPerm = Permission.Query | Permission.Edit;

        // 判断是否有“添加”权限
        if ((userPerm & Permission.Add) == Permission.Add)
        {
            Console.WriteLine("有添加权限");
        }
        else
        {
            Console.WriteLine("没有添加权限");
        }

        // 添加“删除”权限
        userPerm |= Permission.Delete;

        // 移除“查询”权限
        userPerm &= ~Permission.Query;

        Console.WriteLine($"当前权限: {userPerm}");
    }
}