Virtual keyboards are widely used for text input on touch devices currently. However, the traditional virtual keyboard often takes a large portion of precious screen space, which leads to the contradiction between the display output space and the text input space. In order to solve this problem, we have proposed a partial-hidden keyboard with several navigation keys called Navikey. By keeping only a few keys as navigation keys, we reduce the occlusion of the screen display content by the keyboard greatly, and the text input experience is similar to the traditional virtual keyboard. Experiments show that users prefer to choose a partial-hidden keyboard input method which provides more information, which causes the acceptance of NaviKey is much higher than that of a totally hidden keyboard. Moreover, the input speed and accuracy of Navikey are almost the same as the traditional virtual keyboard. This shows that NaviKey can still obtain higher input efficiency and user acceptance while greatly reducing the screen space occupation.