I have installed Qt 5.7 in order to try Qt Charts and Qt Data Visualization but I cannot find new widgets neither in Qt Designer nor in Qt Creator. Any suggestions what should I do so new widgets appear in designer?
I was having exactly the same problem today. It looks like the QT Designer plugins of QT Charts are not part of the package by default. I ended up downloading the designer plugin sources from github https://github.com/qtproject/qtcharts/tree/5.7/plugins/designer
This consists of just 5 files.
You should then be able to open the designer.pro project in Qt Creator and compile it. Place the resulting library in your designer plugin directory. This will make the QChartsView widget appear in the Qt Designer.