Manage fence callbacks

AI-generated Key Takeaways

• After registering a fence, your app needs to add a callback to respond when the fence is triggered.

• Callbacks for fences are implemented using a subclass of BroadcastReceiver to manage Intent methods.

• The BroadcastReceiver.onReceive() method within the subclass handles Intent methods from the fences your app has created.

• The FenceState.extract() method is used to retrieve the fence state from a received Intent and provide it to the callback.

Once a fence is registered, your app must add a callback to respond when the fence is triggered. You can do this with the use of a subclass of BroadcastReceiver to handle Intent methods from fences.

Before you add callbacks to a fence, you must first register the fence.

Create a subclass of BroadcastReceiver

The following example shows the FenceReceiver class, which extends BroadcastReceiver. The class implements the BroadcastReceiver.onReceive() callback method to handle all Intent methods that originate from fences created by your app. When an Intent is received, the FenceState.extract() method is used to get the fence state and pass it to the callback.

public class FenceReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {

        FenceState fenceState = FenceState.extract(intent);

        if (TextUtils.equals(fenceState.getFenceKey(), FENCE_KEY)) {
            String fenceStateStr;
            switch (fenceState.getCurrentState()) {
                case FenceState.TRUE:
                    fenceStateStr = "true";
                    break;
                case FenceState.FALSE:
                    fenceStateStr = "false";
                    break;
                case FenceState.UNKNOWN:
                    fenceStateStr = "unknown";
                    break;
                default:
                    fenceStateStr = "unknown value";
            }
            mLogFragment.getLogView().println("Fence state: " + fenceStateStr);
        }
    }
}