1，在Activity的onStop（）函数中隐藏Widget。
int HomeLauncher::onStop() { QWidget* pObj = mProperty->getUiObj(); if(pObj) { pObj->hide(); } return 0; }
2，在Activity的onDestory中释放掉了改Widget
int HomeLauncher::onDestory() { QWidget* pObj = mProperty->getUiObj(); if(pObj) { pObj->deleteLater(); pObj = NULL; } return 0; }
原文：https://www.cnblogs.com/senior-engineer/p/13184420.html