如何编写Qt Creator之类的调整大小小部件的程序（不使用QSizeGrip）

Question

In Qt Creator we can resize widget by moving mouse cursor to blue square point (mouse cursor will change to arrow shape) then we will press left mouse and pull to change size of widget.

I created a widget and i want to implement that resize idea for it. How can i do it ? Thanks

Answer 1

Ok, so there might be some already implemented solution out there, but that how I would go with:

• Overload those three functions of the parent widget:

   void mousePressEvent(QMouseEvent *event); void mouseReleaseEvent(QMouseEvent *event); void mouseMoveEvent(QMouseEvent *event); 

• Keep track of the initial blue square postition inside the MousePressEvent(...).

• Inside MouseMoveEvent(...) find out the difference between the actual mouse position and the initial one. (Be sure that the user is still clicking ;) ).

• Use the previously found delta and resize the widget accordingly.

• Remember to set a bool or something when the user release the mouse button using the mouseReleaseEvent(...).

Using those steps, you should have a good prototype running.