AbstractThreadedSyncAdapterとは

AbstractThreadedSyncAdapter | Android Developers

Class Overview

An abstract implementation of a SyncAdapter that spawns a thread to invoke a sync operation.

If a sync operation is already in progress when a startSync() request is received then an error will be returned to the new request and the existing request will be allowed to continue.

When a startSync() is received and there is no sync operation in progress then a thread will be started to run the operation and onPerformSync(Account, Bundle, String, ContentProviderClient, SyncResult) will be invoked on that thread.

If a cancelSync() is received that matches an existing sync operation then the thread that is running that sync operation will be interrupted, which will indicate to the thread that the sync has been canceled.

In order to be a sync adapter one must extend this class, provide implementations for the abstract methods and write a service that returns the result of getSyncAdapterBinder() in the service's onBind(android.content.Intent) when invoked with an intent with action android.content.SyncAdapter.

This service must specify the following intent filter and metadata tags in its AndroidManifest.xml file

<intent-filter>
     <action android:name="android.content.SyncAdapter" />
</intent-filter>
<meta-data android:name="android.content.SyncAdapter"
             android:resource="@xml/syncadapter" /> 
  • The android:resource attribute must point to a resource that looks like:
<sync-adapter xmlns:android="http://schemas.android.com/apk/res/android"
     android:contentAuthority="authority"
     android:accountType="accountType"
     android:userVisible="true|false"
     android:supportsUploading="true|false"
     android:allowParallelSyncs="true|false"
     android:isAlwaysSyncable="true|false"
     android:syncAdapterSettingsAction="ACTION_OF_SETTINGS_ACTIVITY"
/>

The android:contentAuthority and android:accountType attributes indicate which content authority and for which account types this sync adapter serves.

android:userVisible defaults to true and controls whether or not this sync adapter shows up in the Sync Settings screen.

android:supportsUploading defaults to true and if true an upload-only sync will be requested for all syncadapters associated with an authority whenever that authority's content provider does a notifyChange(android.net.Uri, android.database.ContentObserver, boolean) with syncToNetwork set to true.

android:allowParallelSyncs defaults to false and if true indicates that the sync adapter can handle syncs for multiple accounts at the same time. Otherwise the SyncManager will wait until the sync adapter is not in use before requesting that it sync an account's data.

android:isAlwaysSyncable defaults to false and if true tells the SyncManager to intialize the isSyncable state to 1 for that sync adapter for each account that is added.

android:syncAdapterSettingsAction defaults to null and if supplied it specifies an Intent action of an activity that can be used to adjust the sync adapter's sync settings. The activity must live in the same package as the sync adapter.

SyncAdapterは同期処理用のスレッドを産み出してくれるようです。
※スレッドはonPerformSync(Account, Bundle, String, ContentProviderClient, SyncResult)を実行

XXSyncServiceのonBind(Intent intent)内でsXXSyncAdapter.getSyncAdapterBinder()してとのこと

AndroidManifest.xmlでのserviceの定義内に以下を必ず置いてとのこと
<intent-filter>
     <action android:name="android.content.SyncAdapter" />
</intent-filter>
<meta-data android:name="android.content.SyncAdapter"
             android:resource="@xml/syncadapter" /> 

そして、metaのresourceは以下のようなものにしてとのこと
 <sync-adapter xmlns:android="http://schemas.android.com/apk/res/android"
    android:contentAuthority="authority"
    android:accountType="accountType"
    android:userVisible="true|false"
    android:supportsUploading="true|false"
    android:allowParallelSyncs="true|false"
    android:isAlwaysSyncable="true|false"
    android:syncAdapterSettingsAction="ACTION_OF_SETTINGS_ACTIVITY"
 />

onPerformSync(Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult)

Perform a sync for this account. SyncAdapter-specific parameters may be specified in extras, which is guaranteed to not be null. Invocations of this method are guaranteed to be serialized.

Parameters
account the account that should be synced
extras  SyncAdapter-specific parameters
authority   the authority of this sync request
provider    a ContentProviderClient that points to the ContentProvider for this authority
syncResult  SyncAdapter-specific parameters

※SyncAdapterに生み出されたスレッドはこのメソッドを呼び出します

getSyncAdapterBinder ()

Returns a reference to the IBinder of the SyncAdapter service.

※XXSyncServiceのonBind(Intent intent)内で呼び出します