在Android手持设备与穿戴设备之间通过蓝牙传递assert(如图片)

开发android wear程序时，经常需要将图片通过Assets 蓝牙传输。

1.创建asset,使用create...()方法，比如传递一个Bitmap传输如下

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private static Asset createAssetFromBitmap(Bitmap bitmap) {

final ByteArrayOutputStream byteStream = new ByteArrayOutputStream();

bitmap.compress(Bitmap.CompressFormat.PNG, 100, byteStream);

return Asset.createFromBytes(byteStream.toByteArray());

}

创建了asset，需要将它指向一个data item，通过使用putAsset（） 方法如下

使用PutDataRequest

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Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.image);

Asset asset = createAssetFromBitmap(bitmap);

PutDataRequest request = PutDataRequest.create("/image");

request.putAsset("profileImage", asset);

Wearable.DataApi.putDataItem(mGoogleApiClient, request);

使用PutDataMapRequest

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Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.image);

Asset asset = createAssetFromBitmap(bitmap);

PutDataRequest request = PutDataRequest.create("/image");

request.putAsset("profileImage", asset);

Wearable.DataApi.putDataItem(mGoogleApiClient, request);

使用PutDataMapRequest

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Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.image);

Asset asset = createAssetFromBitmap(bitmap);

PutDataMapRequest dataMap = PutDataMapRequest.create("/image");

dataMap.getDataMap().putAsset("profileImage", asset)

PutDataRequest request = dataMap.asPutDataRequest();

PendingResult<DataApi.DataItemResult> pendingResult = Wearable.DataApi

.putDataItem(mGoogleApiClient, request);

2. 手表端接收asset

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@Override

public void onDataChanged(DataEventBuffer dataEvents) {

for (DataEvent event : dataEvents) {

if (event.getType() == DataEvent.TYPE_CHANGED &&

event.getDataItem().getUri().getPath().equals("/image")) {

DataMapItem dataMapItem = DataMapItem.fromDataItem(event.getDataItem());

Asset profileAsset = dataMapItem.getDataMap().getAsset("profileImage");

Bitmap bitmap = loadBitmapFromAsset(profileAsset);

// Do something with the bitmap

}

}

}

public Bitmap loadBitmapFromAsset(Asset asset) {

if (asset == null) {

throw new IllegalArgumentException("Asset must be non-null");

}

ConnectionResult result =

mGoogleApiClient.blockingConnect(TIMEOUT_MS, TimeUnit.MILLISECONDS);

if (!result.isSuccess()) {

return null;

}

// convert asset into a file descriptor and block until it's ready

InputStream assetInputStream = Wearable.DataApi.getFdForAsset(

mGoogleApiClient, asset).await().getInputStream();

mGoogleApiClient.disconnect();

if (assetInputStream == null) {

Log.w(TAG, "Requested an unknown Asset.");

return null;

}

// decode the stream into a bitmap

return BitmapFactory.decodeStream(assetInputStream);

}