Qt Simulator Limitations

Qt Simulator is fast and lightweight, but is not the same as an emulator, that means, the real OS of the simulated device is not really running, so it has some limitations.

Screen

The screen of the device is not just a trimmed version of your screen, as the device might have a different pixel density (DPI). That's why the simulator has a slider in the "View" section. When the slider is on "Native size", the simulated device on your screen matches the size of the real device, but maybe you will have less pixels of resolution (devices usually have higher). When the slider is on "Native resolution", your simulated device will use as many pixels of your screen as are available on the real device.

Architecture

Since the application simulated is running in your computer, and there is no hardware emulation at all, you might need to consider that endianess bugs will not be triggered.