NULL Exception in my android program

问题:

Merged with Getting a NullException [duplicate].

i have a crash:

03-16 17:47:57.058: ERROR/AndroidRuntime(609): FATAL EXCEPTION: main
03-16 17:47:57.058: ERROR/AndroidRuntime(609): java.lang.RuntimeException: Unable to      destroy activity {com.TravelPharmacy/com.TravelPharmacy.CountryView}: java.lang.NullPointerException
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:2636)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:2654)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at android.app.ActivityThread.access$2100(ActivityThread.java:117)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:961)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at android.os.Looper.loop(Looper.java:123)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at android.app.ActivityThread.main(ActivityThread.java:3647)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at java.lang.reflect.Method.invokeNative(Native Method)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at java.lang.reflect.Method.invoke(Method.java:507)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at dalvik.system.NativeStart.main(Native Method)
03-16 17:47:57.058: ERROR/AndroidRuntime(609): Caused by: java.lang.NullPointerException
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at com.TravelPharmacy.CountryView.onDestroy(CountryView.java:117)
03-16 17:47:57.058: ERROR/AndroidRuntime(609):     at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:2623)
03-16 17:47:57.058: ERROR/AndroidRuntime(609): 
    ... 11 more

That is the onCreate of First activity, when you press on the button (fromButton) that will call the other activity and expect to get back the name of the country

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);  
    setContentView(R.layout.home);

   // final int recquestCode = 0;
    final Button btnCountryfrom = (Button) findViewById(R.id.fromButton);
    btnCountryfrom.setOnClickListener(new OnClickListener()
    {

        public void onClick(View v)
        {


            Intent pingIntent = new Intent(getApplicationContext(),CountryView.class);
            pingIntent.putExtra("btnText", " ");
            pingIntent.setClass(TravelPharmacy.this, CountryView.class);
            startActivityForResult(pingIntent, RECEIVE_MESSAGE);
            Log.i("tag for easy filter in logcat 6","I am Working!!!");
            ButtonFromPressed=true;

         }



    }); 
}

when getting back the name of the country that be choose in the other activity Override onActivityResult and set the name of country in the button

     @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
    super.onActivityResult(requestCode, resultCode, data);

     Button btnCountryfrom = (Button) findViewById(R.id.fromButton);


        CharSequence seq = data.getCharSequenceExtra("response");
        btnCountryfrom.setText(seq);
        ButtonFromPressed=false;



    }
}

the onCreate of my second Activity

    @Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.country);

    mListUsers = getCountry();
    lvUsers = (ListView) findViewById(R.id.countrylistView);
    lvUsers.setAdapter(new ListAdapter(this, R.id.countrylistView, mListUsers)); 



    lvUsers.setOnItemClickListener(new OnItemClickListener()
    {

        public void onItemClick(AdapterView<?> parent, View view,int position, long id)
        {



            Intent pongIntent = new Intent();

            Log.i("tag for easy filter in logcat 1", "information you provide");

            Log.i("tag for easy filter in logcat 2",mListUsers.get(position).pays);

            pongIntent.putExtra("response",mListUsers.get(position).pays);
            setResult(Activity.RESULT_OK,pongIntent);

            finish();
            Log.i("tag for easy filter in logcat 3",mListUsers.get(position).pays);



        }
     });

}

i will appreciate help!!!

thanks!