SyncAdapter完成后如何通知调用Activity？

Question

在我的Android项目中,我使用自定义SyncAdapter来下载数据并将其存储在本地SQLite数据库中.

public class CustomSyncAdapter extends AbstractThreadedSyncAdapter {

    public CustomSyncAdapter(Context context, boolean autoInitialize) {
        super(context, autoInitialize);
    }

    @Override
    public void onPerformSync(Account account,
                              Bundle extras,
                              String authority,
                              ContentProviderClient provider,
                              SyncResult syncResult) {

        // 1) Download data via AsyncTask
        // 2) Store data via ContentProvider
    }
}

我Activity使用ContentResolver诸如... 来安排主要的同步

ContentResolver.requestSync(account, Authentication.AUTHORITY, bundle);

Activity在同步完成时是否有通用方式通知呼叫？

Answer 1

你可以用它来做到这一点ContentResolver.notifyChange().

所以在你的意思SyncAdapter是这样的:

...
@Override
public void onPerformSync(Account account,
                          Bundle extras,
                          String authority,
                          ContentProviderClient provider,
                          SyncResult syncResult) {

    // 1) Download data via AsyncTask
    // 2) Store data via ContentProvider

    getContext().getContentResolver().notifyChange(<your_content_uri>, null, false);
}
...

然后在Activity中使用ContentResolver.registerContentObserver():

public class MyActivity extends Activity  {

    private ContentObserver mObserver;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...
        mObserver = new ContentObserver(new Handler(Looper.getMainLooper())) {
            public void onChange(boolean selfChange) {
                // Do something.
            }
        };
        getContentResolver().registerContentObserver(<your_content_uri>, mObserver);
    }

    @Override
    public void onDestroy() {
        getContentResolver().unregisterContentObserver(mObserver);
    }
}