如何使用Android Wear的DataItem [英] How to use DataItem of Android Wear

问题描述

我想在手持设备和可穿戴设备之间同步首选项。我在手持式应用程序上实现了示例代码。

I want to sync preference between handhelds and wearables. I implement sample code on handheld app.

PutDataMapRequest dataMap = PutDataMapRequest.create("/count");
dataMap.getDataMap().putInt(COUNT_KEY, count++);
PutDataRequest request = dataMap.asPutDataRequest();
PendingResult<DataApi.DataItemResult> pendingResult = Wearable.DataApi
    .putDataItem(mGoogleApiClient, request);
System.out.println(dataMap.getDataMap().getInt("COUNT_KEY"));//print 3

然后在可穿戴应用程序上实现以下代码。但是保存的计数无法检索。

And then implement below code on wearable app. But saved count can't be retrieved.

 PutDataMapRequest dataMap = PutDataMapRequest.create("/count");
 int count = dataMap.getDataMap().getInt("COUNT_KEY");
 System.out.println(count);//print 0

我实际尝试过android手持设备和Android Wear模拟器。我确认使用Android Wear应用程序的演示卡将它们连接起来。

I tried in actual android handheld device and emulator of Android wear. I confirmed they are connected by using demo cards of Android Wear app.

我需要更多还是我误会了什么？

What I need more or do I misunderstand something?

推荐答案

使用该代码，您试图创建一个第二次放置请求，而不读取先前存储的数据。这就是为什么它为空的原因。

With that code, you are trying to create a second put request, not reading the previously stored data. That's why it's empty.

访问以前存储的数据的方法是使用 DataApi 方法。例如，您可以使用 Wearable.DataApi.getDataItems（）获取所有存储的数据：

The way to access previously stored data is with the DataApi methods. For example, you can get all stored data with Wearable.DataApi.getDataItems():

PendingResult<DataItemBuffer> results = Wearable.DataApi.getDataItems(mGoogleApiClient);
results.setResultCallback(new ResultCallback<DataItemBuffer>() {
    @Override
    public void onResult(DataItemBuffer dataItems) {
        if (dataItems.getCount() != 0) {
            DataMapItem dataMapItem = DataMapItem.fromDataItem(dataItems.get(0));

            // This should read the correct value.
            int value = dataMapItem.getDataMap().getInt(COUNT_KEY);
        }

        dataItems.release();
    }
});

我已经使用了它并且有效。但是，我自己遇到了问题，因为我不知道Uri通过 Wearable.DataApi.getDataItem（）的数据项c>。所以我发布了这个问题。如果您只是进行测试，则 DataApi.getDataItems（）就足够了。

I've used this and it works. However, I'm having a problem myself, as I don't know the Uri to access a specific data item with Wearable.DataApi.getDataItem(). So I posted this question. If you're just testing though, DataApi.getDataItems() should suffice.

另一种选择是使用< a href = http://developer.android.com/reference/com/google/android/gms/wearable/DataApi.html#addListener%28com.google.android.gms.common.api.GoogleApiClient,%20com.google .android.gms.wearable.DataApi.DataListener％29 rel = nofollow noreferrer> DataApi.addListener（） 通知存储更改

Another option is to use DataApi.addListener() to be notified of changes to the storage.

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