如何使用 Android Wear 的 DataItem

How to use DataItem of Android Wear(如何使用 Android Wear 的 DataItem)

问题描述

我想在手持设备和可穿戴设备之间同步偏好.我在手持应用上实现了示例代码.

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

然后在可穿戴应用上实现以下代码.但无法检索已保存的计数.

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

我在实际的安卓手持设备和安卓穿戴模拟器上进行了尝试.我通过 Android Wear 应用的演示卡确认它们已连接.

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.

我还需要什么或者我误解了什么?

What I need more or do I misunderstand something?

推荐答案

使用该代码，您正在尝试创建 第二个 put 请求，而不是读取之前存储的数据.这就是为什么它是空的.

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();
    }
});

我用过这个，它可以工作.但是，我自己也遇到了问题，因为我不知道使用 Wearable.DataApi.getDataItem() 访问 特定 数据项的 Uri.所以我发布了这个问题.如果您只是在测试，DataApi.getDataItems() 应该就足够了.

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 DataApi.addListener() 收到更改通知到存储.

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

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