安卓系统禁止锁屏

1. 修改系统设置默认值：platform/frameworks/base/packages/SettingsProvider/res/values/defaults.xml，将其中的：

<bool name="def_lockscreen_disabled">false</bool>  
<bool name="def_stay_on_while_plugged_in">false</bool>  

这两项的值都改为 true：

<bool name="def_lockscreen_disabled">true</bool>
<bool name="def_stay_on_while_plugged_in">true</bool>

2. 修改 platform/frameworks/base/services/core/java/com/android/server/power/PowerManagerService.java 中

    private void updateStayOnLocked(int dirty) {
        if ((dirty & (DIRTY_BATTERY_STATE | DIRTY_SETTINGS)) != 0) {
            final boolean wasStayOn = mStayOn;
            if (mStayOnWhilePluggedInSetting != 0
                    && !isMaximumScreenOffTimeoutFromDeviceAdminEnforcedLocked()) {
                mStayOn = mBatteryManagerInternal.isPowered(mStayOnWhilePluggedInSetting);
            } else {
                mStayOn = false;
            }

            if (mStayOn != wasStayOn) {
                mDirty |= DIRTY_STAY_ON;
            }
        }
    }

改为：

    private void updateStayOnLocked(int dirty) {
        if ((dirty & (DIRTY_BATTERY_STATE | DIRTY_SETTINGS)) != 0) {
            final boolean wasStayOn = mStayOn;
            if (mStayOnWhilePluggedInSetting != 0
                    && !isMaximumScreenOffTimeoutFromDeviceAdminEnforcedLocked()) {
                mStayOn = mBatteryManagerInternal.isPowered(mStayOnWhilePluggedInSetting);
            } else {
                mStayOn = false;
            }

            mStayOn = true;

            if (mStayOn != wasStayOn) {
                mDirty |= DIRTY_STAY_ON;
            }
        }
    }