Question

我创建了一个计时器，它运行良好。现在我想使用计时器，让我们说，每5秒钟，我将获得用户的位置。然后我测试方法是否有效。所以我将oxy++（MainActivity中的字段）放入其中，并查看它是否真的在每个5secs中运行。然后我遇到了问题。

public class MapsActivity extends BaseActivity /*implements LocationListener*/{

int oxy = 0;

private int isReset = 1;
private TextView textTimer;
private Button startButton;
private Button pauseButton;
private Button resetButton;
private long startTime = 0L;
private Handler myHandler = new Handler();
long timeInMillies = 0L;
long timeSwap = 0L;
long finalTime = 0L;
private String[] navMenuTitles;
private TypedArray navMenuIcons;

private GoogleMap mMap; 
private Button testbtn;
double x;
double y;
double j;
double k;
float dis;
TextView txt;
Location locationA;
Location locationB;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    setUpMapIfNeeded();


    textTimer = (TextView) findViewById(R.id.textTimer);


    startButton = (Button) findViewById(R.id.btnStart);
    startButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            startTime = SystemClock.uptimeMillis();
            myHandler.postDelayed(updateTimerMethod, 0);

            //LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
            //Location locationA = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
            //mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
            //x = locationA.getLatitude();
            //y = locationA.getLongitude();

        }
    });

    pauseButton = (Button) findViewById(R.id.btnPause);
    pauseButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            timeSwap += timeInMillies;
            myHandler.removeCallbacks(updateTimerMethod);

        }
    });

    resetButton = (Button) findViewById(R.id.btnReset);
    resetButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {

            textTimer.setText("0:00:00");
            timeSwap=0;
        }
    });

}

@Override
protected void onResume() {
    super.onResume();
    setUpMapIfNeeded();
}


private void setUpMapIfNeeded() {

    if (mMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                .getMap();
        // Check if we were successful in obtaining the map.
        if (mMap != null) {
            setUpMap();
        }
    }
}

private void setUpMap() {
    mMap.setMyLocationEnabled(true);
}

private Runnable updateTimerMethod = new Runnable() {
    public void run() {
        timeInMillies = SystemClock.uptimeMillis() - startTime;
        finalTime = timeSwap + timeInMillies;
        int seconds = (int) (finalTime / 1000);
        int minutes = seconds / 60;
        seconds = seconds % 60;
        int milliseconds = (int) (finalTime % 1000);
        textTimer.setText("" + minutes + ":"
                + String.format("%02d", seconds) + ":"
                + String.format("%03d", milliseconds));
        myHandler.postDelayed(this, 0);
        int test = (int) (finalTime%5000);
        if (test==0) {
            oxy++;
        }
        txt.setText("o = "+ test+ "  "+ oxy);
    }
};

Runnable updateTimerMethod是一个循环，它每毫秒运行一次。因此，如果我使用秒％5000，它会在每5秒运行，但是氧气保持++本身直到毫秒加起来将秒数增加到6。然后我使用以毫秒为单位的finalTime到％5000。当我重新运行程序时，它不是每5秒工作，氧气+ 1不规则地以5的倍数运行，第一次说25秒，55秒，85秒氧气+ 1。然后我重新运行它，在45s，65s，105s中氧气+ 1。有人能说出它为什么会发生吗？有什么方法可以解决这个问题吗？因为我想用它来获得每50秒一次的位置。在此先感谢！

Answer 1

使用方法Handler.postDelayed对于时间感觉来说不是一个好主意，因为它不够准确。而是使用TimeAnimator（API11 +，或下面的NineOldAndroids）。

TimeAnimator的基本用法：

TimeAnimator anim = new TimeAnimator();
anim.setTimeListener(new TimeAnimator.TimeListener() {
    long time = 0;

    @Override
    public void onTimeUpdate(TimeAnimator timeAnimator, long t, long dt) {
        time += dt;
        if (time >= 5000) { // >= needed because this also might be not totally accurate...
            time -= 5000; // keep the remainder (if there is) to correct the accuracy of next loop

            // do stuff here (in every 5 seconds)
        }
    }
});

Android工作室从我的计时器中获取时间，以便获得距离

1 个答案: