Hi, I think you should put setWidgetReferences() first to initialize the members, then addWidgetListeners()
On Wed, Jun 8, 2011 at 3:20 PM, goAndroid <[email protected]> wrote: > I encounter a crash "java.lang.NullPointerException" whenever I run my > app. please help: > > > ------------------------------------------------------------------------------------------------------------------------------ > package Botton.radio; > > import android.app.Activity; > import android.os.Bundle; > import android.view.View; > import android.view.View.OnClickListener; > import android.widget.Button; > import android.widget.RadioButton; > import android.widget.RadioGroup; > import android.widget.TextView; > import android.widget.RadioGroup.OnCheckedChangeListener; > > public class RadioButtonWidget extends Activity { > public class ClearButtonListener implements OnClickListener { > @Override > public void onClick(View aArg0) { > mRadioGroup.clearCheck(); > mTextView.setText(getString(R.string.selection) + " " > + getString(R.string.none)); > } > } > > public class RadioGroupListener implements OnCheckedChangeListener > { > @Override > public void onCheckedChanged(RadioGroup radioButton, > int idOfSelectedRadioButton) { > if (idOfSelectedRadioButton != -1) { > mRadioButton = (RadioButton) > findViewById(idOfSelectedRadioButton); > mTextView.setText(getString(R.string.selection) + " " > + mRadioButton.getText()); > } > } > > } > > private Button mClearButton; > private RadioButton mRadioButton; > private RadioGroup mRadioGroup; > private TextView mTextView; > > @Override > public void onCreate(Bundle savedInstanceState) { > super.onCreate(savedInstanceState); > setContentView(R.layout.main); > addWidgetListeners(); > setWidgetReferences(); > > } > > private void addWidgetListeners() { > ClearButtonListener aListener = new ClearButtonListener(); > RadioGroupListener rListener = new RadioGroupListener(); > mClearButton.setOnClickListener(aListener); > mRadioGroup.setOnCheckedChangeListener(rListener); > } > > private void setWidgetReferences() { > mClearButton = (Button) findViewById(R.id.clear); > mRadioGroup = (RadioGroup) findViewById(R.id.menu); > mTextView = (TextView) findViewById(R.id.choice); > } > } > > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
