If a particular application is launched, can't it have a similar effect, even if it's not a real shutdown?

<application>
    <service
        android:label="@string/accessibility_service_name"
        android:name=".WindowChangeDetectingService"
        android:permission="android.permission.BIND_ACCESSIBILITY_SERVICE">
        <intent-filter>
            <action android:name="android.accessibilityservice.AccessibilityService"/>
        </intent-filter>
        <meta-data
            android:name="android.accessibilityservice"
            android:resource="@xml/accessibilityservice"/>
    </service>
</application>

public class MyAccessibilityService extends AccessibilityService implements OnInitListener {

    private static final String LOG_TAG = "onAccessibilityEvent";

    @Override
    public void onServiceConnected() {
    }

    @Override
    public void onAccessibilityEvent(AccessibilityEvent event) { 
    //If the app is launched, the Accessibility Event will come in here unconditionally. Why don't you check if it's the app here and if it's right, you can launch the app I set?
        AccessibilityNodeInfo source = event.getSource();
        if (source != null && source.getText() != null) {
            Log.i(LOG_TAG, source.toString());
            Log.i(LOG_TAG, source.getText().toString());
        }
    }


    @Override
    public void onInterrupt() {
        /* /* do nothing */
    }


    @Override
    public void onInit(int status) {
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    @Override
    protected boolean onKeyEvent(KeyEvent event) {
        return false;
    }
}