課題1 MainActivityの実装例

1-2.java

private TextView mText;
private ClockLegacy.ClockListener mListener = new ClockLegacy.ClockListener() {
    @Override
    public void onReceive(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        String dateString = String.format("%02d:%02d", cal.get(Calendar.HOUR_OF_DAY), cal.get(Calendar.MINUTE));
        mText.setText(dateString);
        Log.d("CODELAB", “The current time is " + dateString);
   }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ..
    mText = findViewById(R.id.text);
    mClockData = new ClockLegacy(getApplicationContext());
    final LifecycleObserver observer = new LifecycleObserver() {
        @OnLifecycleEvent(Lifecycle.Event.ON_START)
        public void calledWhenOnStart(LifecycleOwner source) {
           mClockData.setClockListener(mListener);
        }
        @OnLifecycleEvent(Lifecycle.Event.ON_STOP)
        public void calledWhenOnStop(LifecycleOwner source) {
           mClockData.removeClockListener();
        }
    };
    getLifecycle().addObserver(observer);
}