android basics

• There are probably so many things involved. If you understand it, it's about the API.

  • The logic of Android's time-consuming operations cannot be written in the main thread, but must be written in the child thread (I/O stream operations must be time-consuming, and must be written in the child thread)
  • The child thread cannot update the UI interface after Android 2.3, (an error will be reported when the update is performed). If the child thread wants to update the interface, it must be combined with Handler or AsyncTask. In the final analysis, these operations are to update the UI through Handler or AsyncTask. thread do it itself
  • Simple operation of I/O stream (I is input, O is output, don't dislike it, who told us to be grounded)