android - sync_extras_upload 有什么用？

Question

在 ContentResolver 类中，有几个用于同步器的常量。我想知道常量 SYNC_EXTRAS_UPLOAD 有什么用？

Answer 1

如果您 checkin SyncManager.java 文件，您会发现这条评论:

If the ContentResolver.SYNC_EXTRAS_UPLOAD boolean in extras is * true then initiate a sync that just checks for local changes to send * to the server, otherwise initiate a sync that first gets any * changes from the server before sending local changes back to * the server.

在同一个文件中，这是 scheduleLocalSync API 的实现

public void scheduleLocalSync(Account account, String authority) {
    final Bundle extras = new Bundle();
    extras.putBoolean(ContentResolver.SYNC_EXTRAS_UPLOAD, true);
    scheduleSync(account, authority, extras, LOCAL_SYNC_DELAY,
            false /* onlyThoseWithUnkownSyncableState */);
}

syncadapter 的方法 onPerformSync 将这些额外内容作为参数之一接收