(Following the classic Collection of Android Development Materials, a development material involves the following technologies: 1. Establishing a GPRS connection 42. Determining whether the network condition is available 43. Obtaining the inertial sliding direction 54. Disappearance of the arc screen switching dialog 65. TextProssBar displaying text 66. TextView effect 91. TextView's Html effect 92. TextView realizing underline effect 103. Spanned realizing various styles of TextView 107 Get data from the specified server through HttpClient 128, hide keypad 139, respond to Touch1510, and communicate between activities 15)