OpenTok Android SDK Samples

The BaseVideoRenderer class allows you to intercept video frames. To capture a screenshot, you can monitor a property (like saveScreenshot) inside the displayFrame(Frame frame) method. When the property is true, you can extract the ByteBuffer from the Frame object, decode the YUV data into a Bitmap, and save it to storage.

Key steps within displayFrame:

• Access the frame buffer: frame.getBuffer().
• Retrieve dimensions: frame.getWidth() and frame.getHeight().
• Decode the YUV data to an integer array (e.g., using a helper like decodeYUV420).
• Create a Bitmap using Bitmap.createBitmap with Bitmap.Config.ARGB_8888.
• Save the bitmap to the device storage using Bitmap.compress.

@Override
public void displayFrame(Frame frame) {
    // ... frame management logic ...

    if (saveScreenshot) {
        ByteBuffer bb = frame.getBuffer();
        bb.clear();

        int width = frame.getWidth();
        int height = frame.getHeight();
        
        // ... YUV decoding and Bitmap creation logic ...

        Bitmap bmp = Bitmap.createBitmap(intArray, width, height, Bitmap.Config.ARGB_8888);
        
        // Save to file
        File file = new File(Environment.getExternalStorageDirectory().toString(), "opentok-capture-" + System.currentTimeMillis() + ".png");
        // ... stream and compress ...
        
        saveScreenshot = false; // Reset flag
    }
}

The application uses an apiService to perform an asynchronous network call to the CHAT_SERVER_URL. Upon a successful response, it receives a GetSessionResponse object containing the apiKey, sessionId, and token, which are then passed to initializeSession() to start the OpenTok session.

private void getSession() {
    Log.i(TAG, "getSession");

    Call<GetSessionResponse> call = apiService.getSession();

    call.enqueue(new Callback<GetSessionResponse>() {
        @Override
        public void onResponse(Call<GetSessionResponse> call, Response<GetSessionResponse> response) {
            GetSessionResponse body = response.body();
            initializeSession(body.apiKey, body.sessionId, body.token);
        }

        @Override
        public void onFailure(Call<GetSessionResponse> call, Throwable t) {
            throw new RuntimeException(t.getMessage());
        }
    });
}

A ConnectionService allows your app to manage VoIP calls by integrating with Android's Telecom APIs. This enables features like call switching, Bluetooth support, and smartwatch integration.

Self-Managed vs System-Managed

• Self-Managed: Your app handles the connection logic and call management independently. This is achieved by assigning the CAPABILITY_SELF_MANAGED capability to your PhoneAccount.
• System-Managed: The Android system manages the calls. You must use CAPABILITY_CALL_PROVIDER and the user must manually enable the account in system settings. Calls will appear in the device's default call history.

Implementation Lifecycle

To initiate calls, use TelecomManager.placeCall() (outgoing) or TelecomManager.addNewIncomingCall() (incoming). The Telecom framework then binds to your ConnectionService, which must override:

• onCreateOutgoingConnection(): Create a Connection for an outgoing call.
• onCreateIncomingConnection(): Create a Connection for an incoming call.
• onCreateOutgoingConnectionFailed(): Handle failed outgoing call attempts.
• onCreateIncomingConnectionFailed(): Handle failed incoming call attempts (reject silently).

The application uses a Retrofit-style apiService to call the getSession() method on your configured CHAT_SERVER_URL. The server is expected to return a GetSessionResponse containing the apiKey, sessionId, and token. Once received, the app calls initializeSession() to start the OpenTok session.

private void getSession() {
    Log.i(TAG, "getSession");

    Call<GetSessionResponse> call = apiService.getSession();

    call.enqueue(new Callback<GetSessionResponse>() {
        @Override
        public void onResponse(Call<GetSessionResponse> call, Response<GetSessionResponse> response) {
            GetSessionResponse body = response.body();
            initializeSession(body.apiKey, body.sessionId, body.token);
        }

        @Override
        public void onFailure(Call<GetSessionResponse> call, Throwable t) {
            throw new RuntimeException(t.getMessage());
        }
    });
}

The sample uses the ConstraintSet class to define relationships between views (e.g., 'View A is above View B'). A helper class, ConstraintSetHelper, is used to encapsulate these constraints.

Defining relations

To position one view above another, use set.connect() to link the bottom of the upper view to the top of the lower view. Note that you should set the height of the constrained views to 0 to allow the constraints to control their dimensions.

Applying constraints

After defining all constraints in the ConstraintSet, apply them to your ConstraintLayout. You can use TransitionManager.beginDelayedTransition(layout) before applying to enable smooth animations when the layout changes.

// Example of positioning a view above another
public void layoutViewAboveView(int aboveViewId, int belowViewId) {
    set.constrainHeight(aboveViewId, 0);
    set.constrainHeight(belowViewId, 0);
    set.connect(aboveViewId, ConstraintSet.BOTTOM, belowViewId, ConstraintSet.TOP);
    set.connect(belowViewId, ConstraintSet.TOP, aboveViewId, ConstraintSet.BOTTOM);
}

// Applying the set to the layout with animation support
public void applyToLayout(ConstraintLayout layout, boolean animated) {
    if (animated) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            TransitionManager.beginDelayedTransition(layout);
        }
    }
    set.applyTo(layout);
}