It is difficult to start Android programming. The following message is displayed in logcat:
- 01-27 01:42:25. 722: Error/androidruntime (483): Android. content. activitynotfoundexception: unable to find explicit activity class {Org. example. sudoku/android. provider. contacts $ settings}; have you declared this activity in your androidmanifest. XML
Find the same problem on the Internet and find that no activity is declared, but I have already declared it. After a long time, it still cannot be solved. Later I found that the Android. provider. Contacts $ settings statement is a bit incorrect, because my class is in the org. example. Sudoku package. How can this happen? LaterProgramPut the mouse in the place where the activity is called, and find that the pop-up path is indeed not my defined package. Now I understand that settings is a system class. If I name the same class, an error will occur. Set your own setting class to setting. The problem is solved!