android screenlock 源码

Android Screen Lock是一种安全措施，旨在保护用户的个人隐私和数据信息。 它可以在屏幕上使用密码、图案、指纹等方式进行锁定，只有在正确输入锁定方式后才能解锁。Screen Lock源码是安卓操作系统中的一部分，开发者可以通过学习它来深入了解屏幕锁定功能的实现。

在Android系统中，屏幕锁定的源码主要由两部分组成：Lock Screen和Keyguard. Lock Screen是一个运行在后台的服务，负责接收锁定事件并调用相应的解锁服务。Keyguard则是在屏幕上展示锁定界面的一个应用程序，它的主要功能是验证用户输入的密码、图案、指纹等，并根据结果进行解锁。

为了增强安全性，Android系统在屏幕锁定的实现中还引入了一些安全机制。例如，系统在用户输入错误解锁密码、图案、指纹等次数达到一定阈值时，会有一段冷却时间；在解锁时会进行密钥派生，以提高用户密码等的安全性等。

总的来说，Android Screen Lock源码是一个与安全相关的模块，需要开发者具备相应的安全知识，来保护用户的数据不受恶意攻击和非法访问。同时，掌握屏幕锁定功能的实现原理，也有助于开发者在开发应用时针对不同情境，为用户提供更好的安全保障和用户体验。

相关问题

uniapp 如何使用了防截屏功能

在uniapp中，可以使用插件来实现防截屏功能。插件的原理是在应用程序中使用动态模糊或加密等技术，防止应用程序被截屏或录屏。以下是一个使用uniapp防截屏插件的示例：

1. 安装防截屏插件。可以使用npm或yarn等包管理器进行安装，或者将其下载到本地并手动安装。例如，运行以下命令安装uni-app-screen-lock插件：

npm install uni-app-screen-lock --save

2. 在主配置文件（例如App.vue或main.js）中导入并使用插件。例如，在App.vue文件中添加以下代码：

<template>
  <div>
    <!-- 应用程序内容 -->
  </div>
</template>

<script>
import screenLock from 'uni-app-screen-lock';

export default {
  created() {
    // 启用防截屏功能
    screenLock.enable();
  }
}
</script>

3. 在需要使用防截屏功能的页面中，添加screen-lock组件。例如，在某个页面的模板中添加以下代码：

<template>
  <div>
    <screen-lock></screen-lock>
    <!-- 页面内容 -->
  </div>
</template>

需要注意的是，防截屏插件只是一种简单的防截屏方案，不能保证100%防止应用程序被截屏或录屏。因此，在开发应用程序时，还需要考虑其他更加高级的防截屏方案，例如使用硬件加速、加密屏幕内容等。此外，防截屏功能可能会影响应用程序的性能和用户体验，因此需要谨慎使用。

用qbasic编写俄罗斯方块640*240黑白

以下是用 QBASIC 编写的俄罗斯方块游戏，尺寸为 640x240，黑白颜色：

SCREEN 12, , 0, 1

' 定义常量
CONST BLOCK_SIZE = 20
CONST BOARD_LEFT = 80
CONST BOARD_TOP = 20
CONST BOARD_RIGHT = 380
CONST BOARD_BOTTOM = 220
CONST BOARD_WIDTH = BOARD_RIGHT - BOARD_LEFT
CONST BOARD_HEIGHT = BOARD_BOTTOM - BOARD_TOP

' 定义变量
DIM Block(7, 4, 4) AS INTEGER
DIM Board(BOARD_WIDTH \ BLOCK_SIZE + 1, BOARD_HEIGHT \ BLOCK_SIZE + 1) AS INTEGER
DIM x AS INTEGER, y AS INTEGER, c AS INTEGER
DIM cx AS INTEGER, cy AS INTEGER, ci AS INTEGER, cj AS INTEGER
DIM BlockType AS INTEGER, BlockRotation AS INTEGER
DIM GameOver AS INTEGER, Score AS INTEGER

' 初始化方块数据
Block(0,0,0) = 1: Block(0,1,0) = 1: Block(0,2,0) = 1: Block(0,3,0) = 1
Block(1,0,0) = 1: Block(1,1,0) = 1: Block(1,2,0) = 0: Block(1,3,0) = 0
Block(1,0,1) = 0: Block(1,1,1) = 1: Block(1,2,1) = 1: Block(1,3,1) = 0
Block(2,0,0) = 0: Block(2,1,0) = 1: Block(2,2,0) = 1: Block(2,3,0) = 1
Block(2,0,1) = 1: Block(2,1,1) = 1: Block(2,2,1) = 0: Block(2,3,1) = 0
Block(3,0,0) = 1: Block(3,1,0) = 1: Block(3,2,0) = 1: Block(3,3,0) = 0
Block(3,0,1) = 0: Block(3,1,1) = 0: Block(3,2,1) = 1: Block(3,3,1) = 1
Block(4,0,0) = 1: Block(4,1,0) = 1: Block(4,2,0) = 0: Block(4,3,0) = 0
Block(4,0,1) = 0: Block(4,1,1) = 1: Block(4,2,1) = 1: Block(4,3,1) = 1
Block(5,0,0) = 0: Block(5,1,0) = 1: Block(5,2,0) = 0: Block(5,3,0) = 0
Block(5,0,1) = 1: Block(5,1,1) = 1: Block(5,2,1) = 1: Block(5,3,1) = 0
Block(6,0,0) = 0: Block(6,1,0) = 1: Block(6,2,0) = 1: Block(6,3,0) = 0
Block(6,0,1) = 0: Block(6,1,1) = 1: Block(6,2,1) = 1: Block(6,3,1) = 0

' 主循环
DO
    ' 初始化游戏状态
    GameOver = 0
    Score = 0
    FOR i = 0 TO BOARD_WIDTH \ BLOCK_SIZE
        FOR j = 0 TO BOARD_HEIGHT \ BLOCK_SIZE
            Board(i, j) = 0
        NEXT j
    NEXT i
    
    ' 随机选择方块
    BlockType = INT(RND * 7)
    BlockRotation = INT(RND * 4)
    cx = 0: cy = 0
    
    ' 游戏循环
    DO
        ' 绘制游戏界面
        SCREENLOCK
        CLS
        LINE (BOARD_LEFT, BOARD_TOP)-(BOARD_RIGHT, BOARD_BOTTOM)
        FOR i = 0 TO BOARD_WIDTH \ BLOCK_SIZE
            FOR j = 0 TO BOARD_HEIGHT \ BLOCK_SIZE
                x = BOARD_LEFT + i * BLOCK_SIZE
                y = BOARD_TOP + j * BLOCK_SIZE
                IF Board(i, j) THEN
                    CIRCLE (x + BLOCK_SIZE / 2, y + BLOCK_SIZE / 2), BLOCK_SIZE / 2 - 1, 1, , , FILL
                ELSE
                    LINE (x, y)-(x + BLOCK_SIZE - 1, y)
                    LINE (x, y)-(x, y + BLOCK_SIZE - 1)
                    LINE (x + BLOCK_SIZE - 1, y + BLOCK_SIZE - 1)-(x, y + BLOCK_SIZE - 1)
                    LINE (x + BLOCK_SIZE - 1, y + BLOCK_SIZE - 1)-(x + BLOCK_SIZE - 1, y)
                END IF
            NEXT j
        NEXT i
        FOR i = 0 TO 3
            FOR j = 0 TO 3
                IF Block(BlockType, i, j) THEN
                    x = BOARD_LEFT + (cx + i) * BLOCK_SIZE
                    y = BOARD_TOP + (cy + j) * BLOCK_SIZE
                    CIRCLE (x + BLOCK_SIZE / 2, y + BLOCK_SIZE / 2), BLOCK_SIZE / 2 - 1, 1, , , FILL
                END IF
            NEXT j
        NEXT i
        LINE (BOARD_LEFT - 10, BOARD_TOP + 50)-(BOARD_LEFT - 10, BOARD_TOP + 70)
        LINE (BOARD_LEFT - 10, BOARD_TOP + 50)-(BOARD_LEFT - 20, BOARD_TOP + 60)
        LINE (BOARD_LEFT - 10, BOARD_TOP + 50)-(BOARD_LEFT, BOARD_TOP + 60)
        LINE (BOARD_LEFT - 10, BOARD_TOP + 70)-(BOARD_LEFT - 20, BOARD_TOP + 60)
        LINE (BOARD_LEFT - 10, BOARD_TOP + 70)-(BOARD_LEFT, BOARD_TOP + 60)
        PRINT "SCORE: " & Score
        SCREENUNLOCK
        
        ' 等待下一帧
        SLEEP 50
        
        ' 处理方块移动和旋转
        IF KEY(75) THEN cx = cx - 1 ' 左移
        IF KEY(77) THEN cx = cx + 1 ' 右移
        IF KEY(72) THEN BlockRotation = (BlockRotation + 1) MOD 4 ' 顺时针旋转
        IF KEY(80) THEN BlockRotation = (BlockRotation + 3) MOD 4 ' 逆时针旋转
        
        ' 处理方块下落
        IF cy <= BOARD_HEIGHT \ BLOCK_SIZE - 4 THEN
            FOR i = 0 TO 3
                FOR j = 0 TO 3
                    IF Block(BlockType, i, j) THEN
                        ci = cx + i
                        cj = cy + j + 1
                        IF cj <= BOARD_HEIGHT \ BLOCK_SIZE AND Board(ci, cj) = 0 THEN
                            c = c + 1
                        END IF
                    END IF
                NEXT j
            NEXT i
            IF c = 4 THEN
                cy = cy + 1
            ELSE
                FOR i = 0 TO 3
                    FOR j = 0 TO 3
                        IF Block(BlockType, i, j) THEN
                            ci = cx + i
                            cj = cy + j
                            Board(ci, cj) = 1
                        END IF
                    NEXT j
                NEXT i
                EXIT DO
            END IF
        ELSE
            GameOver = 1
            EXIT DO
        END IF
        
        ' 清空计数器
        c = 0
        
        ' 处理消除行
        FOR j = BOARD_HEIGHT \ BLOCK_SIZE DOWNTO 0
            FOR i = 0 TO BOARD_WIDTH \ BLOCK_SIZE
                IF Board(i, j) = 0 THEN EXIT FOR
            NEXT i
            IF i > BOARD_WIDTH \ BLOCK_SIZE THEN
                Score = Score + 1
                FOR k = j TO 1 STEP -1
                    FOR i = 0 TO BOARD_WIDTH \ BLOCK_SIZE
                        Board(i, k) = Board(i, k - 1)
                    NEXT i
                NEXT k
                FOR i = 0 TO BOARD_WIDTH \ BLOCK_SIZE
                    Board(i, 0) = 0
                NEXT i
                j = j + 1
            END IF
        NEXT j
    LOOP
    
    ' 显示游戏结束
    SCREENLOCK
    CLS
    LINE (BOARD_LEFT, BOARD_TOP)-(BOARD_RIGHT, BOARD_BOTTOM)
    FOR i = 0 TO BOARD_WIDTH \ BLOCK_SIZE
        FOR j = 0 TO BOARD_HEIGHT \ BLOCK_SIZE
            x = BOARD_LEFT + i * BLOCK_SIZE
            y = BOARD_TOP + j * BLOCK_SIZE
            IF Board(i, j) THEN
                CIRCLE (x + BLOCK_SIZE / 2, y + BLOCK_SIZE / 2), BLOCK_SIZE / 2 - 1, 1, , , FILL
            ELSE
                LINE (x, y)-(x + BLOCK_SIZE - 1, y)
                LINE (x, y)-(x, y + BLOCK_SIZE - 1)
                LINE (x + BLOCK_SIZE - 1, y + BLOCK_SIZE - 1)-(x, y + BLOCK_SIZE - 1)
                LINE (x + BLOCK_SIZE - 1, y + BLOCK_SIZE - 1)-(x + BLOCK_SIZE - 1, y)
            END IF
        NEXT j
    NEXT i
    LINE (BOARD_LEFT - 10, BOARD_TOP + 50)-(BOARD_LEFT - 10, BOARD_TOP + 70)
    LINE (BOARD_LEFT - 10, BOARD_TOP + 50)-(BOARD_LEFT - 20, BOARD_TOP + 60)
    LINE (BOARD_LEFT - 10, BOARD_TOP + 50)-(BOARD_LEFT, BOARD_TOP + 60)
    LINE (BOARD_LEFT - 10, BOARD_TOP + 70)-(BOARD_LEFT - 20, BOARD_TOP + 60)
    LINE (BOARD_LEFT - 10, BOARD_TOP + 70)-(BOARD_LEFT, BOARD_TOP + 60)
    PRINT "GAME OVER"
    PRINT "SCORE: " & Score
    SCREENUNLOCK
    
    ' 等待重新开始
    DO UNTIL INKEY$ <> ""
LOOP

此代码可能需要在 DOSBox 中运行。