Android5.1 Gallery Gallery2 Code Analysis data loading process

Picture data loading process.

Gallery---->galleryactivity------>albumsetpage------->albumpage--------->photopage

Album set photo set a picture

1,albumsetpage.java

private void Initializedata (Bundle data) {

String MediaPath = data.getstring (Albumsetpage.key_media_path);

Mmediaset = Mactivity.getdatamanager (). Getmediaset (MediaPath);

Mselectionmanager.setsourcemediaset (Mmediaset);

Malbumsetdataadapter = new Albumsetdataloader (

Mactivity, Mmediaset, data_cache_size);

Malbumsetdataadapter.setloadinglistener (New Myloadinglistener ());

}

add back function, when Albumsetdataloader.java when changes occur, update the interface .

2,albumsetdataloader.java

public void Resume () {

Msource.addcontentlistener (Msourcelistener);

Mreloadtask = new Reloadtask ();

Mreloadtask.start ();

Adds a callback function that loads data when the database changes.

3,localalbumset.java (extends MediaSet)

public void Addcontentlistener (Contentlistener listener) {

M: [BUG. MODIFY] Avoid concurrentmodificationexception @{

/*mlisteners.put (listener, NULL); */

Synchronized (Weak_hash_map_lock) {

Mlisteners.put (listener, NULL);

}

Increase the callback to deal directly with the database.

4,datamanager.java

Public synchronized void Initializesourcemap () {

if (!msourcemap.isempty ()) return;

The order matters, the UriSource must come last

Addsource (New Localsource (mapplication));

New Localsource.java

5,localsource.java (extends MediaSource)

@Override

Public mediaobject createmediaobject (path Path) {

Galleryapp app = Mapplication;

Switch (mmatcher.match (path)) {

Case Local_all_albumset:

Case Local_image_albumset:

Case Local_video_albumset:

return new Localalbumset (path, mapplication);

New Localalbumset

6,localalbumset.java (extends MediaSet)

Public Localalbumset (path path, Galleryapp application) {

Super (Path, Nextversionnumber ());

mapplication = Application;

Mhandler = new Handler (Application.getmainlooper ());

Mtype = Gettypefrompath (path);

Mnotifier = new Changenotifier (this, mwatchuris, application);

Mname = Application.getresources (). GetString (

R.string.set_label_local_albums);

}

private static final uri[] Mwatchuris =

{Images.Media.EXTERNAL_CONTENT_URI, Video.Media.EXTERNAL_CONTENT_URI};

will monitor the image and video URLs to be monitored Add to Changenotifier the.

7,changenotifier.java

Public Changenotifier (MediaSet set, uri[] URIs, Galleryapp application) {

Mmediaset = set;

for (int i = 0; i < uris.length; i++) {

Application.getdatamanager (). Registerchangenotifier (Uris[i], this);

Register the URL.

8,datamanager.java

public void Registerchangenotifier (Uri uri, Changenotifier notifier) {

Notifybroker broker = NULL;

Synchronized (MNOTIFIERMAP) {

Broker = Mnotifiermap.get (URI);

if (broker = = null) {

Broker = new Notifybroker (Mdefaultmainhandler);

Mapplication.getcontentresolver ()

. Registercontentobserver (URI, true, broker);

Mnotifiermap.put (URI, broker);

}

}

Broker.registernotifier (notifier);

}

the URL and Notifybroker to associate, when the URL Callback class broker is called when a change occurs

9,datamanager.java

private static class Notifybroker extends Contentobserver {

@Override

Public synchronized void OnChange (Boolean selfchange) {

For (Changenotifier Notifier:mNotifiers.keySet ()) {

Notifier.onchange (Selfchange);

}

}

when the URL is called when a change occurs. Notifier.onchange (Selfchange)

----- àmmediaset.notifycontentchanged ();(Changenotifier.java)

-- àlistener.oncontentdirty ();(Localalbumset.java (extends MediaSet))

Android5.1 Gallery Gallery2 Code Analysis data loading process