Android手机如何判断有没有锁屏密码

今天来到新公司接收到的第一个任务就是这个，调研有没有方式判断Android手机有没有锁屏密码，最初的想法是自己以前写过一下程序锁的实现原理，去监听历史任务栈，看第一个程序是不是就是程序锁，结果失败告终，问了一个以前的朋友，了解到keyguard这个类，Google一下，看Keyguard解锁屏机制这个介绍的比较详细。大概了解了锁屏的原理。不多说了，直接进入正题

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Google有几种默认的锁屏方式

public static final int PASSWORD_QUALITY_ALPHABETIC = 262144;//字母密码    public static final int PASSWORD_QUALITY_ALPHANUMERIC = 327680;//字母数字密码    public static final int PASSWORD_QUALITY_BIOMETRIC_WEAK = 32768;    public static final int PASSWORD_QUALITY_COMPLEX = 393216;//复杂密码，我没有测试到    public static final int PASSWORD_QUALITY_NUMERIC = 131072;//数字密码    public static final int PASSWORD_QUALITY_NUMERIC_COMPLEX = 196608; //复杂数字密码    public static final int PASSWORD_QUALITY_SOMETHING = 65536;//图案密码    public static final int PASSWORD_QUALITY_UNSPECIFIED = 0;//无密码

下面问题来了，如何获取这些状态呢，通过看KeyGuard类，了解到，这个类里面判断模式的都是通过LockPatternUtils类去获取锁屏时的密码模式的，该类是在 frameworks 层的，Android内置的，无法直接访问。

找了一下资料，在stackoverflow上看到一个如下写的代码：

 boolean isLock = android.provider.Settings.System.getInt(                getContentResolver(), Settings.System.LOCK_PATTERN_ENABLED, 0) == 1;

判断isLock真假来判断如否有屏幕锁，该方法经过测试，在无密码的状态是可以，在图案密码的情况下也是可以的，但是在数字密码的情况下不行，此方式行不通。还是换回第一种思路

在googlesources上查看LockPatternUtils代码
看到有好几个获取锁屏模式的方法：
getActivePasswordQuality（）：

 /**     * Used by device policy manager to validate the current password     * information it has.     */    public int getActivePasswordQuality() {        int activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED;        // Note we don't want to use getKeyguardStoredPasswordQuality() because we want this to        // return biometric_weak if that is being used instead of the backup        int quality =                (int) getLong(PASSWORD_TYPE_KEY, DevicePolicyManager.PASSWORD_QUALITY_SOMETHING);        switch (quality) {            case DevicePolicyManager.PASSWORD_QUALITY_SOMETHING:                if (isLockPatternEnabled()) {                    activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_SOMETHING;                }                break;            case DevicePolicyManager.PASSWORD_QUALITY_BIOMETRIC_WEAK:                if (isBiometricWeakInstalled()) {                    activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_BIOMETRIC_WEAK;                }                break;            case DevicePolicyManager.PASSWORD_QUALITY_NUMERIC:                if (isLockPasswordEnabled()) {                    activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_NUMERIC;                }                break;            case DevicePolicyManager.PASSWORD_QUALITY_ALPHABETIC:                if (isLockPasswordEnabled()) {                    activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_ALPHABETIC;                }                break;            case DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC:                if (isLockPasswordEnabled()) {                    activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC;                }                break;            case DevicePolicyManager.PASSWORD_QUALITY_COMPLEX:                if (isLockPasswordEnabled()) {                    activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_COMPLEX;                }                break;        }        return activePasswordQuality;    }

getKeyguardStoredPasswordQuality（）：

    /**     * Retrieves the quality mode we're in.     * {@see DevicePolicyManager#getPasswordQuality(android.content.ComponentName)}     *     * @return stored password quality     */    public int getKeyguardStoredPasswordQuality() {        int quality =                (int) getLong(PASSWORD_TYPE_KEY, DevicePolicyManager.PASSWORD_QUALITY_SOMETHING);        // If the user has chosen to use weak biometric sensor, then return the backup locking        // method and treat biometric as a special case.        if (quality == DevicePolicyManager.PASSWORD_QUALITY_BIOMETRIC_WEAK) {            quality =                (int) getLong(PASSWORD_TYPE_ALTERNATE_KEY,                        DevicePolicyManager.PASSWORD_QUALITY_SOMETHING);        }        return quality;    }

看注释，getKeyguardStoredPasswordQuality不建议使用，于是反射LockPatternUtils调用getActivePasswordQuality方法获取锁屏模式
代码如下：

private boolean isPhoneHasLock() {        String LOCKSCREEN_UTILS = "com.android.internal.widget.LockPatternUtils";        try {            Class<?> lockUtilsClass = Class.forName(LOCKSCREEN_UTILS);            Object lockUtils = lockUtilsClass.getConstructor(Context.class).newInstance(this);            try {                Method method = lockUtilsClass.getMethod("getActivePasswordQuality");                Integer mode = (Integer) method.invoke(lockUtils);                if (mode == DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED) {                    return false;                } else {                    return true;                }            } catch (Exception e) {        } catch (Exception e) {            Log.e("reflectInternalUtils", "ex:" + e);        }        return false;    }

通过该方法就可以判断Android手机是否有解屏密码了。

* 注意，该方法需要在屏幕点亮的广播中调用，才能及时判断用户是否有解屏密码。*

顺带把注册屏幕开关的代码也附上，以后查找方便

  IntentFilter mScreenOnFilter = new IntentFilter("android.intent.action.SCREEN_ON");   this.registerReceiver(mScreenOReceiver, mScreenOnFilter);   private BroadcastReceiver mScreenOReceiver = new BroadcastReceiver() {        @Override        public void onReceive(Context context, Intent intent) {            String action = intent.getAction();            if (action.equals("android.intent.action.SCREEN_ON")) {        isPhoneHasLock();            }         }    };

第一次用markdown写blog，写完啦。仅供同行学习，欢迎指导！