Android training project: based on memory card music player V03 (training log)

The first stage of the training project: Based
on the memory card music player V03 1. On the basis of the memory card music player V0.2, add functions:
1. Add a music playlist (display the song name) and
click on a piece of music It will play immediately, the playing progress will be cleared, and the playing time of the current music will be displayed.
2. Add a [Previous] and [Next] buttons. When the
current music is the first song, click the [Previous] button to switch to the last music.
When the current music is the last one, click the [Next] button to switch to the first music.
3. When a certain piece of music is finished playing, it will automatically switch to the next piece of music to play.
Many problems were encountered during this process. When creating a sub-package, the location of the package name was incorrect, which caused the program to fail to run.