Working with sqlite in AsyncTask
lazarus / 43-Android

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las · 2019-05-09 21:31

Hi!
I'm trying to work with sqlite in AsyncTask. But if I create
jSqliteDataAccess in the process of the program, and not put on the
form, it does not work. If I pass a link to jSqliteDataAccess, located
on the form of a procedure that works in AsyncTask, then a Java
exception occurs. After several calls to Sqlite (most likely because
from AsyncTask you cannot access objects running in the main thread).
How can I work with sqlite in AsyncTask?

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jmpessoa · 2019-05-10 02:09

Hi, las!

I can try implement:

SelectAsync  
DropTableAsync
CreateTableAsync
InsertIntoTableAsync
UpdateTableAsync, ...
[and others.... whats?]

and  events to  handle/notify  about the  tasks...

What about?

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las · 2019-05-10 12:06

I run a procedure that loads several dozen files across the network
and puts the data into the sqlite database. The whole procedure lasts
about a minute. Implementing one asynchronous database query will not
help. It is necessary to change the algorithm of work. It would be
very helpful to be able to run several execSQL in one transaction
(several thousand queries pass).

However, the question remains: why if I create jSqliteDataAccess
programmatically, then it does not work if it is not on the form? What
is wrong?

Like that:
db: = jSqliteDataAccess.Create (self);
db.init (gApp);
db.cursor: = jSqliteCursor.Create (db.Owner);
db.cursor.init (gApp);

The same situation with jTextFileManager. If I just write as below,
then the application falls. And if you put jTextFileManager on the
form, then everything works.

fm: = jTextFileManager.Create (AndroidModule1);
fm.Init (gApp);

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jmpessoa · 2019-05-12 03:22

Quote It would be very helpful to be able to run several execSQL in
one transaction....

Done!

Added build-in  transaction and boolean result to 
"InsertIntoTableBatch"  method
Added build-in  transaction and boolean result to  "UpdateTableBatch" 
method

and

Added "ExecSQLBatchAsync" [build-in  transaction] method   [can be
used to "Insert" or "Update" ...  etc...]
Added  event "OnAsyncPostExecute" to notify Async task result....

Added SetBatchAsyncTaskType to remind  ExecSQLBatchAsync state....

Please, test it!

Quotewhy if I create jSqliteDataAccess programmatically, then it does
not work if it is not on the form? What is wrong?

This is a LAMW limitation ... you need to have at least one component
of this type on form for the dynamic/runtime component creation to
work....