A free app for Android, by Popoko VM Games.

Four in a Row is an exciting and challenging game that you can play with other people. It is a game that can be played by 2 people, where the players take turns dropping colored discs from the top into a 7-column, 6-row vertically suspended grid. The players then have to connect 4 of the same color discs in a line of 4, or make a horizontal, vertical, or diagonal connection. 

There are many ways to connect the 4 colors, and it is possible to make a connection in any direction. If you connect 4 of your own color discs, you will gain points. If your opponent connects 4 of his or her color discs, then you will lose the game.