Introduction
Android provides two ways for me to use speech recognition.
The first way is by an Intent, as in this question: Intent example. A new Activity is pushed onto the top of the stack which listens to the user, hears some speech, attempts to transcribes it (normally via the cloud) then returns the result to my app, via an onActivityResult call.
The second is by getting a SpeechRecognizer, like the code here: SpeechRecognizer example. Here, it looks like the speech is recorded and transcribed on some other thread, then callbacks bring me the results. And this is done without leaving my Activity.
I would like to understand the pros and cons of these two ways of doing speech recognition.
What I’ve got so far
Using the Intent:
- is simple to code
- avoids reinventing the wheel
- gives consistent user experience of speech recognition across the device
but
- might be slow for the creation of a new activity with it’s own window
Using the SpeechRecognizer:
- lets me retain control of UI in my app
- gives me extra possibilities of things to respond to (documentation)
but
- is limited to be called from the main thread
- more control requires more error-checking.
In addition to all this, I’d add at least this point:
SpeechRecognizeris better for hands-free user interfaces, since your app actually gets to respond to error conditions like “No matches” and perhaps restart itself. When you use theIntent, the app beeps and shows a dialog that the user must press to continue.My summary is as follows:
SpeechRecognizer
Show different UI or no UI at all. Do you really want your app’s UI to beep? Do you really want your UI to show a dialog when there is an error and wait for user to click?
App can do something else while speech recognition is happening
Can recognize speech while running in the background or from a
service
Can Handle errors better
Can access low level speech stuff like the raw audio or the RMS. Analyze that audio or use the loudness to make some kind of flashing light to indicate the app is listening
Intent