1. A method for operating an electronic device, comprising: displaying a list comprising a plurality of shortened text messages on a flexible screen in respective cells, wherein each size of corresponding unshortened text messages exceeds a size of a respective cell of the list; receiving a selection of at least one shortened text message among the plurality of shortened text messages on the flexible screen in a significantly flat state; and in response to detecting a convex bending of the flexible screen, displaying an unshortened text message of the at least one shortened text message selected in the significantly flat state.