5.扫描二维码
扫描二维码，其实比上面只多了一步，就是把camera获取的东西直接转换，然后进行识别。
public void requestPreviewFrame(Handler handler, int message) {
if (camera != null && previewing) {
previewCallback.setHandler(handler, message);
if (useOneShotPreviewCallback) {
camera.setOneShotPreviewCallback(previewCallback);
} else {
camera.setPreviewCallback(previewCallback);
}
}
}
首先把camera预览的数据放入previewCallback中。
final class PreviewCallback implements Camera.PreviewCallback
public void onPreviewFrame(byte[] data, Camera camera) {
Point cameraResolution = configManager.getCameraResolution();
if (!useOneShotPreviewCallback) {
camera.setPreviewCallback(null);
}
if (previewHandler != null) {
Message message = previewHandler.obtainMessage(previewMessage, cameraResolution.x,
cameraResolution.y, data);
message.sendToTarget();
previewHandler = null;
} else {
Log.d(TAG, "Got preview callback, but no handler for it");
}
}
可以看到，预览的数据data，回传递过来，然后handler的方式传递出去。
接收data的地方：
@Override
public void handleMessage(Message message) {
switch (message.what) {
case R.id.decode:
//Log.d(TAG, "Got decode message");
decode((byte[]) message.obj, message.arg1, message.arg2);
break;
case R.id.quit:
Looper.myLooper().quit();
break;
}
}
然后是decode data
private void decode(byte[] data, int width, int height) {
long start = System.currentTimeMillis();
Result rawResult = null;
//modify here
byte[] rotatedData = new byte[data.length];
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++)
rotatedData[x * height + height - y - 1] = data[x + y * width];
}
int tmp = width; // Here we are swapping, that's the difference to #11
width = height;
height = tmp;
PlanarYUVLuminanceSource source = CameraManager.get().buildLuminanceSource(rotatedData, width, height);
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
try {
rawResult = multiFormatReader.decodeWithState(bitmap);
} catch (ReaderException re) {
// continue
} finally {
multiFormatReader.reset();
}
if (rawResult != null) {
long end = System.currentTimeMillis();
Log.d(TAG, "Found barcode (" + (end - start) + " ms):n" + rawResult.toString());
Message message = Message.obtain(activity.getHandler(), R.id.decode_succeeded, rawResult);
Bundle bundle = new Bundle();
bundle.putParcelable(DecodeThread.BARCODE_BITMAP, source.renderCroppedGreyscaleBitmap());
message.setData(bundle);
//Log.d(TAG, "Sending decode succeeded message...");
message.sendToTarget();
} else {
Message message = Message.obtain(activity.getHandler(), R.id.decode_failed);
message.sendToTarget();
}
}
当把camera上的图片转换成BinaryBitmap以后，剩下的事情，就更直接从图片识别是一样的。
