The ornamental design for a portabledeviceholder, as shown and described.
FIG. 1 is a front perspective view of a portable device holder showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof, the right side elevation view being a mirror image thereof;
FIG. 5 is a top plan view thereof, the bottom plan view being a mirror image thereof;
FIG. 6 is a front perspective view thereof, shown with the portable device holder in an extended position;
FIG. 7 is a front perspective view thereof; shown with the portable device holder in a retracted position and in a condition of use with a portable device disclosed in broken lines to illustrate an environment;
FIG. 8 is a front perspective view thereof, shown with the portable device holder in an extended position;
FIG. 9 is a front perspective view thereof; shown with a human hand disclosed in broken lines to illustrate an environment; and,
FIG. 10 is a top plan view thereof; shown with a substrate disclosed in broken lines to illustrate an environment.
The broken lines showing a portable device, a human hand and a substrate in FIGS. 7-10 represent environmental structure and form no part of the claimed design.