Resched. timer after cancel gives “java.lang.IllegalStateException: Timer cancelled.”

Question

i would like to know whether i can schedule the timer again after i cancelled it. It was stated here, http://www.coderanch.com/t/452066/java/java/Exception-timer-IllegalStat

Answer 1

@Alan Moore: Hi, i guess i finally did it! this is the code that was able to perform wifi scan and send back the response back to the calling activity using Broadcast intent.

LargeImageScoll.java (Activity)

Intent intent;

public static Runnable scanTask;

public BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        //updateUI(intent); 
        //String returnedValue = intent.getStringExtra("data");
        Bundle bundle = intent.getExtras();
        String returnedValue = bundle.getString("data");
        Log.e("Waht", returnedValue);
    }
};

private static Handler handler = new Handler(){

    @Override
    public void handleMessage(Message msg) {
        // TODO Auto-generated method stub
        super.handleMessage(msg);
    }

};

public class LargeImageScroller extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
        setContentView(new SampleView(this));

        intent = new Intent(this, WifiScanning.class);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {...}

@Override
public boolean onOptionsItemSelected(MenuItem item) {...}

//this is the class where the program would do all the UI and display images
private static class SampleView extends View {

    public SampleView(Context context) {
                :
    loadMap load = new loadMap();
    load.execute(context);

    scanTask = new Runnable(){
    @Override
    public void run() {
    // TODO Auto-generated method stub
    startService(new Intent(context, WifiScanning.class));  
    };

    handler.removeCallbacks(scanTask);
    handler.postDelayed(scanTask, refreshRate);
}

public boolean onTouchEvent(MotionEvent event) {...}
protected void onDraw(Canvas canvas) {...}
private static Drawable LoadImageFromWebOperations(String url){...}
private static Bitmap decodeFile(File f, int requiredSize){...}
private class loadMap extends AsyncTask>{...}

}//end of SampleView

protected void onResume() {
    // TODO Auto-generated method stub
    Log.e("AndroidRuntime", "onResume");
    handler.removeCallbacks(scanTask);
    handler.postDelayed(scanTask, refreshRate);
    registerReceiver(broadcastReceiver, new IntentFilter(WifiScanning.BROADCAST_ACTION));
    super.onResume();
}

@Override
protected void onStop() {
    // TODO Auto-generated method stub
    Log.e("AndroidRuntime", "onStop");
    unregisterReceiver(broadcastReceiver);
    stopService(new Intent(this, WifiScanning.class));
    handler.removeCallbacks(scanTask);
    super.onStop();
}
}//end of LargeImageScroll

WifiScanning.java (Service)

public static final String BROADCAST_ACTION = "android.wps.wifiscanning.broadcasttest";
int counter = 0;
Intent intent1;
WifiReceiver receiverWifi = new WifiReceiver();
WifiManager wifi;
StringBuilder sb;
List wifiList;

public void onCreate() {
    super.onCreate();

    intent1 = new Intent(BROADCAST_ACTION); 
    Log.e(TAG, "Service creating");
    wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
    registerReceiver(receiverWifi, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
    if(counter==0){
    Log.e("AndroidRuntime", "Scan for the "+counter+" time");
    wifi.startScan();
    counter++;
    }
}

class WifiReceiver extends BroadcastReceiver {
    public void onReceive(Context c, Intent intent) {
        sb = new StringBuilder();
        wifiList = wifi.getScanResults();
        for(int i = 0; i < wifiList.size(); i++){
            sb.append("["+ (wifiList.get(i).SSID).toString() + "][");
            sb.append((wifiList.get(i).BSSID).toString() + "][");
            sb.append((String.valueOf(wifiList.get(i).level)) + "]");
            sb.append("\n");
        }
        Log.e("AndroidRuntime", sb.toString());
        if(counter<4){
            Log.e("AndroidRuntime", "Scan for the "+counter+" time");
            wifi.startScan();
            counter++;
        }else{
            intent1 = new Intent(BROADCAST_ACTION);
            String test = sb.toString();
            intent1.putExtra("data", test);
            sendBroadcast(intent1);
        }
    }
}

@Override
public void onDestroy() {
    // TODO Auto-generated method stub
    unregisterReceiver(receiverWifi);
    super.onDestroy();
}