having trouble with 'onTouchEvent' in android

Question

I'm practicing on Android development by watching Thenewboston's videos.

From one of his videos, I'm trying to create an onTouchEvent(), but I'm getting error: Java.lang.NullPointerException.

The newboston 134 number tutorial

What should I do?

now the whole code is:

    package com.chupamobile.android.googlemaps;

import java.util.List;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.MotionEvent;

import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;

public class GoogleMapsActivity extends MapActivity {

    MapView map;
    Long start, stop;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        map = (MapView) findViewById(R.id.mymap);
        map.setBuiltInZoomControls(true);

        Touchy t = new Touchy();
        List<Overlay> overlayList = map.getOverlays();
        overlayList.add(t);
    }

    @Override
    protected boolean isRouteDisplayed() {
        // TODO Auto-generated method stub
        return false;
    }

    class Touchy extends Overlay {
        public boolean onTouchEvent(MotionEvent e, MapView m) { 
            if (e.getAction() == MotionEvent.ACTION_DOWN) {
                start = e.getEventTime();
            }
            if (e.getAction() == MotionEvent.ACTION_UP) {
                stop = e.getEventTime();
            }
            if (stop - start > 1500) {
                AlertDialog alert = new AlertDialog.Builder(
                        GoogleMapsActivity.this).create();
                alert.setTitle("Pick an option");
                alert.setMessage("I told u pick an option");
                alert.setButton("Place a pin",
                        new DialogInterface.OnClickListener() {

                            @Override
                            public void onClick(DialogInterface dialog,
                                    int which) {
                                // TODO Auto-generated method stub

                            }
                        });
                alert.show();
                return true;
            }

            return false;
        }
    }
}

my error list:

Warning: 10-16 10:06:57.106: E/MapActivity(1649): Couldn't get connection factory client


10-16 10:07:03.645: W/dalvikvm(1649): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
10-16 08:17:31.174: W/dalvikvm(1349): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
10-16 08:17:31.334: E/AndroidRuntime(1349): FATAL EXCEPTION: main
10-16 08:17:31.334: E/AndroidRuntime(1349): java.lang.NullPointerException
10-16 08:17:31.334: E/AndroidRuntime(1349):     at com.chupamobile.android.googlemaps.GoogleMapsActivity$Touchy.onTouchEvent(GoogleMapsActivity.java:45)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at com.google.android.maps.OverlayBundle.onTouchEvent(OverlayBundle.java:63)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at com.google.android.maps.MapView.onTouchEvent(MapView.java:679)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.View.dispatchTouchEvent(View.java:5541)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1951)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1712)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1957)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1684)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1957)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1684)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1957)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1684)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1957)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1684)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1912)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1371)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.app.Activity.dispatchTouchEvent(Activity.java:2364)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1860)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.View.dispatchPointerEvent(View.java:5721)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:2890)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2466)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewRootImpl.processInputEvents(ViewRootImpl.java:845)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2475)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.os.Looper.loop(Looper.java:137)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at android.app.ActivityThread.main(ActivityThread.java:4424)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at java.lang.reflect.Method.invokeNative(Native Method)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at java.lang.reflect.Method.invoke(Method.java:511)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
10-16 08:17:31.334: E/AndroidRuntime(1349):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

in my code above i have used Long start, stop; instead of long start, stop; that was the error.

Answer 2

u can do as below.

say you need to fire touch(i.e click event i guess) in button,than in your xml code add this

android:onClick=onClick

and in your activity just after your oncreate method write this

public void onClick(View v){

   switch(v.getId()){

      case R.id.urbuttonid:{

        Log.e("click event fired?","yes");        

        break;

      }

   }

}

after doing this check your log

Answer 3

Try creating an OnTouchListner.

example

    button.setOnTouchListener(new View.OnTouchListener() 
    {

        public void onClick(View v) 
        {
            }