android textclock怎样处理更新频率

?Android?,TextClock?????????????/????????TextClock?????,?????Handler?Runnable???????????,??????TextClock???????5?:

1. ?????(??activity_main.xml)?????TextClock??:

2. ?Activity(??MainActivity.java)?,??Handler?Runnable???????:

import android.os.Handler;
import android.os.SystemClock;
import android.widget.TextClock;

public class MainActivity extends AppCompatActivity {

    private TextClock textClock;
    private Handler handler;
    private Runnable runnable;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textClock = findViewById(R.id.textClock);

        // ????Handler??
        handler = new Handler();

        // ????Runnable??,????TextClock???
        runnable = new Runnable() {
            @Override
            public void run() {
                updateTextClock();
                handler.postDelayed(this, 5000); // ?5?????
            }
        };

        // ????TextClock???
        handler.post(runnable);
    }

    private void updateTextClock() {
        // ??????
        String currentTime = getCurrentTime();

        // ??TextClock???
        textClock.setFormat24Hour(currentTime);
    }

    private String getCurrentTime() {
        // ??????????????
        return String.format("d:d", SystemClock.elapsedRealtime() / 1000 % 24, SystemClock.elapsedRealtime() / 1000 % 60);
    }
}

??????,???????Handler?????Runnable???Runnable????????updateTextClock???,??????????????TextClock??????,????handler.postDelayed(this, 5000)?Runnable?????Handler?,???5????????,????handler.post(runnable)????TextClock????