SyncAdapter完成同步后如何刷新Android ListView

2019-11-12 02:27:41 阅读：202 来源： 互联网

我扩展了AbstractThreadedSyncAdapter并使其每隔x分钟或当我手动通过代码请求同步时自动与服务器同步数据.它运作完美.

因此,下一步是自动更新包含消息的ListView和另一个包含分配的作业的ListView.

我发现的所有示例都假定您正在同一Activity中更改数据集,否则您可以访问ListView绑定到的数据库游标.不幸的是,对于Android同步适配器,情况并非如此.据我所知,它在后台运行,没有引用任何有用的东西.

我的SyncAdapter：

public class VttSyncAdapter extends AbstractThreadedSyncAdapter {
    private final AccountManager mAccountManager;

    public VttSyncAdapter(Context context, boolean autoInitialize) {
        super(context, autoInitialize);
        mAccountManager = AccountManager.get(context);
    }

    @Override
    public void onPerformSync(Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult) {
        Log.d("Vtt", "onPerformSync for account[" + account.name + "]");
        try 
        {         
            //GET SOME DATA FROM WEBSERVICE AND INSERT INTO SQLITE DB
        } catch (IOException e) {
            e.printStackTrace();
        }

        //WHAT WOULD ONE DO HERE TO ALERT THE LISTVIEW THAT IT SHOULD REFRESH?

        } catch (Exception e) {
            e.printStackTrace();

    }

    public String getsharedresourcestring(String key)
    {
        Context context = getContext();
        SharedPreferences sharedPref = context.getSharedPreferences(context.getString(R.string.preference_file_key), MODE_PRIVATE);
        return sharedPref.getString(key,null);
    }

}

我的时间表片段代码：

public class ScheduleFragment extends Fragment {
    private ListView listView;
    private List<DeliveryScheduleEntryModel> schedules;


    public ScheduleFragment() {
        // Required empty public constructor
    }

    public static ScheduleFragment newInstance(String param1, String param2) {
        ScheduleFragment fragment = new ScheduleFragment();
        Bundle args = new Bundle();
        //args.putString(ARG_PARAM1, param1);
        //args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            //mParam1 = getArguments().getString(ARG_PARAM1);
            //mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View ret = inflater.inflate(R.layout.fragment_schedule, container, false);

        listView = (ListView) ret.findViewById(R.id.listViewSchedule);

        //GET OUR DATA
        Activity activity = this.getActivity();
        ContentResolver contentResolver = activity.getContentResolver();
        schedules = getSchedule(contentResolver);

        DeliveryScheduleEntryModelList customList = new DeliveryScheduleEntryModelList(activity, schedules);

        listView.setAdapter(customList);
        return ret;
    }

    public List<DeliveryScheduleEntryModel> getSchedule(ContentResolver cr)
    {
        Context context = getContext();
        VttDataSource db = new VttDataSource(context);
        db.open();
        List<DeliveryScheduleEntryModel> ret = db.getAllDeliveryScheduleEntryModel();
        db.close();

        return ret;
    }
}

解决方法:

//WHAT WOULD ONE DO HERE TO ALERT THE LISTVIEW THAT IT SHOULD REFRESH?

发送这样的本地广播：

Intent intent = new Intent();
intent.setAction("com.your_package.name.REFRESH_LIST");
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);

让带有ListView的Fragment声明一个BroadcastReceiver：

private BroadcastReceiver myReceiver = new BroadcastReceiver()
{
    @Override
    public void onReceive(Context context, Intent intent)
    {

        String sAction = intent.getAction();
        if ("com.your_package.name.REFRESH_LIST".equals(sAction) )
        {
            // update the ListView here
        }
    }
}

注册BroadcastReceiver,例如在onAttach()中：

IntentFilter myFilter = new IntentFilter();
myFilter.addAction("com.your_package.name.REFRESH_LIST");
LocalBroadcastManager.getInstance(this).registerReceiver(myReceiver, myFilter);

并且不要忘记注销例如在onDetach()中

LocalBroadcastManager.getInstance(this).unregisterReceiver(myReceiver);

这样,只要将Fragment附加到Activity,它将获得更新消息.

另一种选择是使用某种类型的事件总线(greenrobot,Otto …).

标签：listview,synchronization,android
来源： https://codeday.me/bug/20191112/2023911.html

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SyncAdapter完成同步后如何刷新Android ListView