Handheld device and input method thereof

An input method for use in a handheld device, the handheld device comprising a touch screen and a processor, the touch screen being configured to sense a touch to generate a touch signal and display a user interface, the user interface comprising an input zone, the input zone defining a plurality of input scrolling bars and at least one switch scrolling bar, and each of the input scrolling bars having a primary character-symbol and at least one secondary character-symbol, the input method being executed by the processor and comprising the following steps of:

• (a) determining that the touch is a sliding action and the touch signal corresponds to a target input scrolling bar among the input scrolling bars or to the at least one switch scrolling bar of the input zone;
• (b) when the touch signal corresponds to the target input scrolling bar among the input scrolling bars of the input zone, changing the primary character-symbol of the target input scrolling bar into another primary character-symbol and changing the at least one secondary character-symbol of the target input scrolling bar into another at least one secondary character-symbol according to a first sliding direction corresponding to the sliding action so as to generate an input signal corresponding to the another primary character-symbol, and changing the another primary character-symbol presented by the target input scrolling bar back into the primary character-symbol after the input signal is generated, wherein the another primary character-symbol corresponds to one of the at least one secondary character-symbol, one of the another at least one secondary character-symbol corresponds to the primary character-symbol;
• and
• (c) when the touch signal corresponds to the at least one switch scrolling bar of the input zone, simultaneously changing the primary character-symbol and the at least one secondary character-symbol of each of the input scrolling bars according to a second sliding direction corresponding to the sliding action.