ListFragment和SupportMapFragment选择同步 [英] Synchronize ListFragment and SupportMapFragment selection

问题描述

我有两个看法基本上是相同的数据：

I have 2 views of essentially the same data:

1. <一个href="https://$c$c.google.com/p/wheelly/source/browse/src/com/wheelly/fragments/LocationsListFragment.java?name=dev"相对=nofollow>在android.support.v4.app项目列表。 ListFragment
2. 在<一个标记href="https://$c$c.google.com/p/wheelly/source/browse/src/com/wheelly/fragments/LocationsMapFragment.java?name=dev"相对=nofollow>地图在com.google.android.gms.maps。 SupportMapFragment

1. List of items in a android.support.v4.app.ListFragment
2. Markers on a map in a com.google.android.gms.maps.SupportMapFragment

以上两者都使用装载机的模式，以获得相同的数据（扩展的 LoaderCallbacks ，查询的ContentProvider ，等等）

Both of the above are using loader pattern to obtain the same data (extending LoaderCallbacks, querying ContentProvider, and so on)

这两个都在一个<托管href="https://$c$c.google.com/p/wheelly/source/browse/src/com/wheelly/activity/LocationsList.java?name=dev"相对=nofollow>活动内ViewPager 。

什么将是最好的策略，为这两个片段同步当前选中的列表项/标记？ （想想我的位置编辑UI，或者方向的谷歌地图与自己的左侧窗格中，并在该中心的地图）。

What will be the best strategy to synchronize currently selected list item / marker for both of these fragments? (Think of "My Places" edit UI, or "Directions" of the Google Maps with their left-hand pane and a map in the center).

情景我在想，到目前为止的：

Scenarios i'm thinking of so far:

1. 请每一个片段手动通知它的对手有关通过回调接口选择的变化（这可能会涉及到基本活动，协调跨段通信，因为它是建议由Android的文档）。
2. 在以某种方式使两个片段使用相同的光标，甚至ListAdapter（不管它意味着一个地图，因为现在它从光标直接填充）。
3. （别的东西吗？）

也许有人已经处理了这个确切的情况？ （我肯定会找到一些解决办法，只是想避免重新发明轮子对不起了过于概念化的问题。）

Maybe someone has already dealt with this exact case? (I'll sure find some solution, just wanted to avoid "reinventing the wheel". Sorry for a too conceptual question.)

修改（解决方案）

我觉得马切伊已经回答了我的确切问题（这样的最好的策略，和..），这样的答案都是 1 和 2 ; - ）

I think Maciej has answered my exact question ("best strategy", and so on..), so the answers are both 1 and 2 ;-)

走进更多的细节，我的实现是这样的：

Going into more details, my implementation went like this:

起初我吓坏了与发布/订阅模式在Java中处理的巨大开销（包括界面，找到合适的地方回调，什么是不）。幸运的是，奥托总线实施吸引了我的目光，这让碎片一件微不足道的小事之间的通信。它不仅可以通知有关选择改变所有用户，也是整个装载机啪很好地适应：

At first I frightened by enormous overhead of dealing with publisher/subscriber pattern in Java (involving interfaces, finding proper places for callbacks, and what's not). Fortunately, Otto bus implementation caught my eyes, which made communication between fragments a trivial thing. Not only it is possible to notify all subscribers about selection change, but also the whole Loader Patter fit nicely:

1. 这是奥托的样品code借BusProvider类。

1. Borrow BusProvider class from Otto's sample code.

创建一些消息，合同履行通知数据：

Create few message contracts to carry notification data:

public class LocationSelectedEvent {  
    public long id;  
}  

public class LocationsLoadedEvent {  
    public Cursor cursor;  
}  

在注释碎片接收器的方法@Subscribe（下面的例子是装载机情况下，选择改变它没有更多的复合物）：

Annotate "receiver" methods in fragments with @Subscribe (example below is for loader case, for selection change it's no more complex):

@Subscribe
public void onLoadFinished(LocationsLoadedEvent event) {  
    final CursorAdapter a = (CursorAdapter) getListAdapter();  
    a.swapCursor(event.cursor);  
}  

请碎片听来的通知：

Make fragments "listening" to notifications:

@Override  
public void onActivityCreated(Bundle savedInstanceState) {  
    BusProvider.getInstance().register(this);  
}  

请片段停止听时，他们不是活着（专为片段API真正了解到硬盘的方式）：

Make fragments to stop listening when they're not "alive" (specially true for fragments API, learned it the hard way):

@Override  
public void onDestroy() {  
    super.onDestroy();  
    BusProvider.getInstance().unregister(this);  
}  

最后，在需要触发通知（例如下面deomnstrates如何从通知的 LocationList 当光标已加载的活动）：

Finally, trigger notifications where desired (example below deomnstrates how to notify from LocationList activity when cursor has been loaded):

@Override
public void onResume() {
    if(null == getLoaderManager().getLoader(0)) {
        getSupportLoaderManager().initLoader(0, null, new LoaderCallbacks<Cursor>() {
            @Override
            public Loader<Cursor> onCreateLoader(int paramInt, Bundle paramBundle) {
                return new CursorLoader(LocationsList.this, Locations.CONTENT_URI, null, null, null, null);
            }

            @Override
            public void onLoadFinished(Loader<Cursor> paramLoader, Cursor cursor) {
                BusProvider.getInstance().post(new LocationsLoadedEvent(cursor));
            }

            @Override
            public void onLoaderReset(Loader<Cursor> paramLoader) {
                BusProvider.getInstance().post(new LocationsLoadedEvent(null));
            }
        });
    }
    super.onResume();
}

奖励：通知流程的可视化

Bonus: notifications flow visualization

推荐答案

对于点击协调你1点是我会做什么，当然使用的活性和接口。

For click-coordination your point 1 is what I would do, using Activity and interfaces of course.

我只是很难理解为什么你想从的ContentProvider 加载相同的数据的两倍。为什么不一次在一个共享对象加载它？在应用程序的一些对象，注射单，或甚至另一个片段，该通知活动完毕，并且将数据推送到你的两个片段？

I just have hard time understanding why would you want to load the same data from ContentProvider twice. Why not load it once in a shared object? Some object inside Application, injected singleton or even another Fragment, which notifies Activity of data load complete and it pushes data to your two Fragments?

这篇关于ListFragment和SupportMapFragment选择同步的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！