7 Segment Common Cathode LED Digit Display Circuit for Arduino
Further to my comment - you need a high side switch.
For example:

Q2 is a jellybean NPN type (such as a bc548). If the base voltage of Q2 is below 0.6 V it is OFF, more than 0.6V it is ON. The output from an arduino (3V3 or 5V) can easily operate it. Note that the high resistance values means the arduino doesn't have to supply lots of current to enable the switch.
Q1 (bc327) is the PNP version of the bc337. When Q2 is OFF (input LOW), Q1 is off and no current can flow to the segment.
When Q2 is ON (input HIGH), Q1 is ON and current flows. You may need to limit the segment current with a resistor.
You'll need this circuit (or something similar) for each segment you wish to drive.