官方示例virtualBoard

虚拟键盘在有些板子上不显示，添加如下QQuickWindow::setSceneGraphBackend(QSGRendererInterface::Software);后可显示，但是运行时出现两个问题。

问题

问题1

QML debugging is enabled. Only use this in a safe environment.
QBackingStore::endPaint() called with active painter on backingstore paint device
QBackingStore::endPaint() called with active painter on backingstore paint device
QBackingStore::endPaint() called with active painter on backingstore paint device
QBackingStore::endPaint() called with active painter on backingstore paint device
QBackingStore::endPaint() called with active painter on backingstore paint device
QBackingStore::endPaint() called with active painter on backingstore paint device
QBackingStore::endPaint() called with active painter on backingstore paint device
QBackingStore::endPaint() called with active painter on backingstore pain