Getting a NullException [duplicate]

This question already exists: Closed 11 years ago.

Possible Duplicate:

NULL Exception in my android program

Have an Exception:

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", "informati开发者_如何转开发on 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);



        }
     });

}

The onDestroy() for my second Activity.

    @Override
public void onDestroy()
 {

    //     adapter.imageLoader.stopThread();
    //mListUsers=null;


   lv.setAdapter(null);
   super.onDestroy();
 }

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
android:id="@+id/widget142"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
xmlns:android="http://schemas.android.com/apk/res/android"
>
<RelativeLayout
android:id="@+id/widget143"
android:layout_height="33px"
android:background="@color/blue"
android:layout_width="fill_parent">
<ImageButton
android:id="@+id/homeImageButton"
android:layout_width="47px"
android:layout_height="34px"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
>
</ImageButton>
<TextView
android:id="@+id/countryTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Country"
android:textSize="20sp"
android:textStyle="bold"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
>
</TextView>
</RelativeLayout>
<ListView
    android:id="@+id/countrylistView" 
android:layout_width="match_parent" android:layout_height="250px">
</ListView>
</LinearLayout>

i will appreciate help!!!

thanks!

---

Check if the ListAdapter exist on R.layout.country where it looks like you are getting the problem:

findViewById(R.id.countrylistView);

Because your listView have not been instatiated. Can you post the country layout

---

ListAdapter is an interface so you can't new a ListAdapter unless you have created a class named ListAdapter somewhere, that's probably a bad idea and you should use a different name.

When creating an Adapter you pass in a layout for the list item, not the id of the ListView.

---

Since you have posted your question in another thread, it is clear that the problem is that lv is never initialized in your activity before you call setAdapter in onDestroy(), causing a NullPointerException since it is null, as it is shown in this snippet of your code:

@Override
public void onDestroy()
 {

    //     adapter.imageLoader.stopThread();
    //mListUsers=null;


   lv.setAdapter(null);
   super.onDestroy();
 }

Also, when you want to post more data about your problem, just edit your question instead of creating a new one :) I hope this helps.

---

Could it be, that

mListUser is null or mListUsers.get(position) is null?