Android 登录锁定机制：基于设备运行时间的可靠实现

// Constants.kt
object LockConfig {
    const val PREF_NAME = "account_lock_prefs"
    const val KEY_ERROR_COUNT = "error_count"
    const val KEY_LOCK_UNTIL = "lock_until"      // 锁定截止时间（基于elapsedRealtime）
    const val KEY_LAST_ELAPSED = "last_elapsed"  // 上次设备运行时间
    const val MAX_ATTEMPTS = 5
    const val LOCK_DURATION_MS = 10 * 60 * 1000L // 10分钟（毫秒）
}

class LoginActivity : AppCompatActivity() {
    private val prefs by lazy { 
        getSharedPreferences(LockConfig.PREF_NAME, MODE_PRIVATE) 
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        detectSystemReboot()
    }

    /** 检测设备是否重启并重置状态 */
    private fun detectSystemReboot() {
        val currentElapsed = SystemClock.elapsedRealtime()
        val lastElapsed = prefs.getLong(KEY_LAST_ELAPSED, 0L)

        // 当前时间小于上次记录时间 = 设备已重启
        if (currentElapsed < lastElapsed) {
            prefs.edit {
                putInt(KEY_ERROR_COUNT, 0)
                putLong(KEY_LOCK_UNTIL, 0L)
            }
        }

        // 更新设备运行时间记录
        prefs.edit { putLong(KEY_LAST_ELAPSED, currentElapsed) }
    }
}

class LoginActivity : AppCompatActivity() {
    // ...

    fun attemptLogin(username: String, password: String) {
        val (errorCount, lockUntil) = prefs.run {
            getInt(KEY_ERROR_COUNT, 0) to getLong(KEY_LOCK_UNTIL, 0L)
        }
        val currentElapsed = SystemClock.elapsedRealtime()

        // 检查锁定状态
        if (lockUntil > currentElapsed) {
            showLockMessage(lockUntil - currentElapsed)
            return
        }

        when {
            isValidCredentials(username, password) -> handleLoginSuccess()
            else -> handleLoginError(errorCount, currentElapsed)
        }
    }

    private fun showLockMessage(remainingMs: Long) {
        val minutes = remainingMs / 60000
        Toast.makeText(this, "请等待 ${minutes} 分钟后再试", LENGTH_SHORT).show()
    }

    private fun handleLoginSuccess() {
        prefs.edit {
            putInt(KEY_ERROR_COUNT, 0)
            putLong(KEY_LOCK_UNTIL, 0L)
        }
        startActivity(Intent(this, MainActivity::class.java))
    }

    private fun handleLoginError(errorCount: Int, currentElapsed: Long) {
        val newCount = errorCount + 1
        prefs.edit {
            if (newCount >= MAX_ATTEMPTS) {
                putLong(KEY_LOCK_UNTIL, currentElapsed + LOCK_DURATION_MS)
                Toast.makeText(this, "错误次数过多，请10分钟后重试", LENGTH_SHORT).show()
            } else {
                Toast.makeText(this, "密码错误，剩余尝试次数: ${MAX_ATTEMPTS - newCount}", LENGTH_SHORT).show()
            }
            putInt(KEY_ERROR_COUNT, newCount)
        }
    }
}

val current = SystemClock.elapsedRealtime() // 当前设备运行时间
val last = prefs.getLong(KEY_LAST_ELAPSED, 0)

if (current < last) { 
    // 设备已重启，因为运行时间不可能倒流
    resetLockState() 
}

stateDiagram-v2
    [*] --> Idle: 初始状态
    Idle --> Locked: 连续错误5次
    Locked --> Idle: 10分钟到期或设备重启
    Locked --> Idle: 成功登录