问题
I am writing an Android app that needs to be notified whenever a given SQLite database changes (any new row added, deleted or updated).
Is there any programmatic way to listen to these notifications ?
Is writing DB triggers for each table the only way ?
回答1:
SQLite provides Data Change Notification Callbacks. I don't think that Android exposes them directly but it does have for example CursorAdapter which provides some change notifications.
As thinksteep asked however, do you expect your DB to be changed outside the scope of your own application?
回答2:
You can register an observer class such as DataSetObserver
Then whenever you change something you can call cursor.registerDataSetObserver(..) to register observe changes.
It's not well documented but I'm sure that there are some examples out there
回答3:
You can use also use the getContentResolver().registerContentObserver but unfortunately it doesn't tell you what kind of change was made, it could be a delete, insert or update.
If you control the ContentProvider that interfaces with the DB then you could fire an Intent or use getContentResolver().notifyChange to send a special Uri notification that identifies both the table and action. An example Uri you could notify with might be: content://my-authority/change/table-name/insert
But even then you don't know exactly which rows were effected by the change.
Seems like triggers that write to a change log table will guarantee you hear about all changes regardless of where they came from, and you can know the exact id and action that occurred. Unfortunately it means slower inserts/updates/deletes and it means you probably need a Service of some kind to process and delete changes.
I'd love to hear if these is some better solution out there!
来源：https://stackoverflow.com/questions/8783963/android-sqlite-db-notifications