Database and Listview do not work

Question

I’m trying to create an app that records data and displays it in a Listview, and then gradually sophisticate the app, but when it comes to saving the data in the database, it doesn’t save. In Debug it runs everything right, in the last line, as it is in the image below, out of nowhere it returns "false". The strange thing is that he seems to be searching for the data. And the id always returns "0" I don’t understand why.

Then I also discovered that my Arraylist doesn’t seem to work either. Every time I go to the part of my app to show recorded data (The Fragment that corresponds to Listview) the app closes itself. Using Debug I discovered two details, one in Datasource and the other in Fragment where I program to show the data that is saved. Normally I would think that since there is no recorded data, then it will not work. But I think the app should not close alone, at most it should only show a blank screen.

The weirdest thing is that I’ve worked with another application using virtually the same code templates, so I don’t understand why so many problems.

Answer 1

Try this code it puts the insert operation within a data transaction context that is opened with the method beginTransaction() is the data is passed to the database by the method setTransactionSuccessful() and the transaction context is closed by the method endTransaction()

public boolean insert(String tabela, ContentValues dados) { 
   boolean sucesso = true; 
   //Abre um contexto de transação.
   db.beginTransaction();
   try { 
         // >= pois a tabela pode estar vazia e rowID pode ser 0;
         sucesso = db.insert(tabela, null, dados) >= 0; 
         // Valida o contexto de transação.
         db.setTransactionSuccessful();
   } catch (Exception e) { 
         //  Seria interessante fazer um log dessa exceção 
         //para saber se está havendo erro de comunicação com o banco de dados
         sucesso = false; 
   } finally {
     // Finaliza o contexto de transação.
     db.endTransaction();
   }
   return sucesso;
}