我有一个应用程序，用于绘制当前用户的位置与另一个活动的邮政编码之间的路线。除了一个功能外，一切都很好。我通过处理程序/ runnable机制实现了一个计时器。如果在预定时间内没有触摸显示器，例如2分钟，那么我返回到用户必须再次登录的菜单屏幕。这是我的应用程序的安全功能。
我已经重写了dispatchTouchEvent方法，以便当用户触摸屏幕时，重置计时器。此部分无法正常工作。无论用户是否触摸屏幕，应用程序都会进入菜单屏幕。
我认为如果我将处理程序和runnable设置为null并在再次启动计时器之前删除对runnable的所有回调将起作用。
任何人都可以告诉我如何取消当前的runnable并重新启动它。
这是完整的代码，谢谢。亚光。
public class GetClientDirections extends MapActivity implements LocationListener{
private MapController mapController;
private MapView mapView;
private List<Overlay> mapOverlays;
private StringBuffer response = null;
private static final String TAG = GetClientDirections.class.getSimpleName();
private double lon;
private double lat;
private JSONArray routes = null;
private JSONObject bounds = null;
private JSONObject northeast = null;
private JSONObject anonObject;
private JSONObject overViewPolyline;
private String stringUrl;
private String polyPoints;
Context context;
private String endAddr;
private GeoPoint startAddr;
BroadcastReceiver locationChangereceiver;
double lati;
double lngi;
boolean isTrafficOn;
SharedPreferences appSharedPrefs;
Handler handler;
Runnable runnable;
String rotaAutoLogout;
int rotaAutoLogoutAsInt;
final String QRCODE_ACTION = "com.carefreegroup.QRCODE_ACTION";
NfcScannerApplication nfcscannerapplication;
private LocationManager locationManager;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mapview);
Intent intent = this.getIntent();
String postcode = intent.getStringExtra("postcode");
Log.e(TAG, "postcode = " + postcode);
appSharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);
nfcscannerapplication = (NfcScannerApplication) getApplication();
context = this;
endAddr = postcode;
isTrafficOn = false;
rotaAutoLogout = appSharedPrefs.getString("120", null);
rotaAutoLogoutAsInt = Integer.parseInt(rotaAutoLogout);
if(rotaAutoLogoutAsInt > 0){
initHandler();
handler.postDelayed(runnable, rotaAutoLogoutAsInt * 1000);
}
}// end of onCreate
public void initHandler(){
handler = new Handler();
runnable = new Runnable() {
public void run() {
returnToMenu();
}
private void returnToMenu() {
Intent intent2 = new Intent(GetClientDirections.this,
NfcscannerActivity.class);
intent2.setAction(QRCODE_ACTION);
intent2.putExtra("carerid", nfcscannerapplication.getCarerID());
startActivity(intent2);
}
};
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
Log.e(TAG, "screen touched");
if(rotaAutoLogoutAsInt > 0){
handler.removeCallbacks(runnable);
handler = null;
runnable = null;
initHandler();
handler.postDelayed(runnable, rotaAutoLogoutAsInt * 1000);
Log.e(TAG, " reset timer");
}
return super.dispatchTouchEvent(ev);
}
@Override
protected void onPause() {
locationManager.removeUpdates(this);
handler.removeCallbacks(runnable);
super.onPause();
}
@Override
protected void onResume() {
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
handler.removeCallbacks(runnable);
initHandler();
handler.postDelayed(runnable, rotaAutoLogoutAsInt * 1000);
super.onResume();
}
@Override
protected void onStop() {
handler.removeCallbacks(runnable);
super.onStop();
}
private class AsyncGetRoute extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... params) {
getRoute();
return null;
}
@Override
protected void onPostExecute(Void result) {
String jsonOutput = response.toString();
Log.e(TAG, "jsonOutput = " + jsonOutput);
JSONObject results = null;
try {
results = new JSONObject(jsonOutput);
routes = results.getJSONArray("routes");
anonObject = routes.getJSONObject(0);
bounds = anonObject.getJSONObject("bounds");
overViewPolyline = anonObject.getJSONObject("overview_polyline");
polyPoints = overViewPolyline.getString("points");
Log.e(TAG, "overview_polyline = " + overViewPolyline);
Log.e(TAG, "points = " + polyPoints);
northeast = bounds.getJSONObject("northeast");
lat = (Double) northeast.get("lat");
lon = (Double) northeast.get("lng");
Log.e(TAG, "lon/lat = " + lon + " " + lat);
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
List<GeoPoint> list = decodePoly(polyPoints);
mapView = (MapView) findViewById(R.id.cfmapview);
mapView.setBuiltInZoomControls(true);
mapView.setEnabled(true);
mapView.setSatellite(true);
mapController = mapView.getController();
mapController.setZoom(10);
mapOverlays = mapView.getOverlays();
mapOverlays.clear();
mapOverlays.add(new RoutePathOverlay(list, getApplicationContext()));
mapController.animateTo(new GeoPoint(list.get(0).getLatitudeE6(), list
.get(0).getLongitudeE6()));
mapView.invalidate();
super.onPostExecute(result);
}
}
public void getRoute() {
response = new StringBuffer();
URL url = null;
try {
url = new URL(stringUrl);
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
HttpURLConnection httpconn = null;
try {
httpconn = (HttpURLConnection) url.openConnection();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
if (httpconn.getResponseCode() == HttpURLConnection.HTTP_OK) {
// Log.e(TAG,"response code OK ");
BufferedReader input = new BufferedReader(
new InputStreamReader(httpconn.getInputStream()), 8192);
String strLine = null;
while ((strLine = input.readLine()) != null) {
// Log.e(TAG,""+strLine);
response.append(strLine);
}
input.close();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}// end of getRoute
private List<GeoPoint> decodePoly(String encoded) {
List<GeoPoint> poly = new ArrayList<GeoPoint>();
int index = 0, len = encoded.length();
int lat = 0, lng = 0;
while (index < len) {
int b, shift = 0, result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lat += dlat;
shift = 0;
result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lng += dlng;
GeoPoint p = new GeoPoint((int) (((double) lat / 1E5) * 1E6),
(int) (((double) lng / 1E5) * 1E6));
poly.add(p);
}
return poly;
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
@Override
public void onLocationChanged(Location location) {
lati = (location.getLatitude());
lngi = (location.getLongitude());
startAddr = new GeoPoint((int)(lati*1000000.0), (int)(lngi*1000000.0));
Log.e(TAG, "lat = " + lati);
Log.e(TAG, "lon = " + lngi);
Log.e(TAG, "lat after cast = " + (int)(lati * 1000000));
Log.e(TAG, "lon after cast = " + (int)(lngi * 1000000));
locationManager.removeUpdates(this);
StringBuilder sb = new StringBuilder();
sb.append("http://maps.google.com/maps/api/directions/json?origin=");
//sb.append(startAddr);
sb.append(lati);
sb.append(",");
sb.append(lngi);
sb.append("&destination=");
sb.append(endAddr);
sb.append("&sensor=false");
stringUrl = sb.toString();
Log.e(TAG, "url = " + stringUrl);
AsyncGetRoute agr = new AsyncGetRoute();
agr.execute();
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.layout.menutogglemapview, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.satellite:
mapView.setSatellite(true);
return true;
case R.id.terrain:
mapView.setSatellite(false);
return true;
case R.id.traffic:
if(isTrafficOn == false){
mapView.setTraffic(true);
isTrafficOn = true;
}else{
mapView.setTraffic(false);
isTrafficOn = false;
}
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
答案 0 :(得分：1)
您可以使用以下方法简化与启动/停止此计时器相关的所有代码：
//Generic Task Start/Stop
private Handler mHandler = new Handler();
private void startTimer(Runnable Task, long delay) {
mHandler.removeCallbacks(Task);
mHandler.postDelayed(Task, delay);
}
private void stopTimer(Runnable Task) {
mHandler.removeCallbacks(Task);
}
//Now your specific code
private Runnable tReturnToMenu = new Runnable() {
public void run() {
returnToMenu();
}
};
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
Log.e(TAG, "screen touched");
if(rotaAutoLogoutAsInt > 0){
stopTimer(tButtonFadeOut);
startTimer(tButtonFadeOut);
Log.e(TAG, " reset timer");
}
return super.dispatchTouchEvent(ev);
}
问候。