Android contentobserver monitors changes in contact data

1. ContentProvider is a content provider

Contentresolver is the content resolver (operating on the data provided by the content)

Contentobserver is a content observer (observing changes in data provided by content providers)

2. Contentobserver needs contentresolver to register.

resolver.registerContentObserver(uri,true,observer)；

① Uri (first parameter): the URI of the ContentProvider that this listener listens on

② Notifyfordescendants (second parameter): set to true. (if the requested URI is content: / / ABC, the URI is content: / / ABC / XYZ, and any data change will be detected.

③ Observer: listener instance.

3. Using the onchange method in observer, when the data changes, the callback method is automatically executed.

① define observer listener

② get the contact contentresolver

③ register observer.

④ important point: add access rights (also dynamic)

⑤ log off observer

[prompt]: here, the observer is written in the form of an internal class. There is only this part of the code, and there is no need to add others.

① contentobserver can timely detect the data changes provided by ContentProvider.

② contentobserver can communicate between programs not only provided by the system, but also created by itself through contentobserver and contentresolver