null exception.
It's easy to make such a stupid mistake if you've been off Java/Android for a while.
First, it's null exception in regards of View.
1: @Override
2: protected void onCreate(Bundle savedInstanceState) {
3: super.onCreate(savedInstanceState);
4: mTextView = (TextView) findViewById(R.id.textview);
5: mTextView.setText("JunEnd");
6: setContentView(R.layout.activity_register);
7: }
setContentView() sets the activity content from a layout resource, so should be called before findViewById(). Otherwise findViewById() will return null because of no layout resource and thus line 5 throws a null exception.Second, it's null exception in regards of Spinner.
1: public class RegisterActivity extends Activity implements OnItemSelectedListener {
2: private Spinner mSpinner;
3: private ArrayList<String> mArrayList_SpinnerList;
4: @Override
5: protected void onCreate(Bundle savedInstanceState) {
6: super.onCreate(savedInstanceState);
7: setContentView(R.layout.activity_register);
8: ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
9: android.R.layout.simple_spinner_item, mArrayList_SpinnerList);
10: adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
11: mSpinner.setAdapter(adapter);
12: mSpinner.setOnItemSelectedListener(this);
13: }
14: @Override
15: public void onItemSelected(AdapterView<?> parent, View view, int pos,
16: long id) {
17: // TODO Auto-generated method stub
19: }
20: @Override
21: public void onNothingSelected(AdapterView<?> arg0) {
22: // TODO Auto-generated method stub
23: }
24: }
I forgot to instantiate mArrayList_SpinnerList and passed it to constructor ArrayAdapter() and then thus gave Spinner this adapter holding an uninstantiated object. I believe this is causing a null exception and killed the app.
