Can't set OnCheckedChangeListener to a Checkbox
You can't set the listener for your CheckBox
from the ListView
like that(it will probably throw a NullPointerException
), instead set the listener in the getView()
method(you'll also have to keep the CheckBox
status so you don't end up with strange rows status). Bellow is an example:
public class ListViewActivity extends ListActivity {
public class MyCustomAdapter extends ArrayAdapter<String> {
private ArrayList<Boolean> status = new ArrayList<Boolean>();
public MyCustomAdapter(Context context, int textViewResourceId,
String[] objects) {
super(context, textViewResourceId, objects);
for (int i = 0; i < objects.length; i++) {
status.add(false);
}
}
@Override
public View getView(final int position, View convertView,
ViewGroup parent) {
View row = convertView;
if (row == null) {
LayoutInflater inflater = getLayoutInflater();
row = inflater.inflate(R.layout.adapters_listviewactivity_row,
parent, false);
}
TextView label = (TextView) row.findViewById(R.id.weekofday);
label.setText(month[position]);
CheckBox checkBox = (CheckBox) row.findViewById(R.id.checkBox);
checkBox.setOnCheckedChangeListener(new OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
Toast.makeText(getApplicationContext(), "" + position,
Toast.LENGTH_SHORT).show();
if (isChecked) {
status.set(position, true);
} else {
status.set(position, false);
}
}
});
checkBox.setChecked(status.get(position));
return row;
}
}
String[] month = { "January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December" };
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setListAdapter(new MyCustomAdapter(ListViewActivity.this,
R.layout.main, month));
}
}
For the TextView
you'll have to do the same thing.
Implement CheckBox Listener for your class this way, especially if you have more than one CheckBox to deal with, you can handle in switch case blocks and makes your code neater:
public class MyClass extends AppCompatActivity implements
CompoundButton.OnCheckedChangeListener,{
CheckBox myCheckBox;
}
In your onCreate() method put this:
myCheckBox = (CheckBox)findViewById(R.Id.myCheckBoxName_in_XML_layout);
mmyCheckBox.setOnCheckedChangeListener(this);
Listern for your checkbox view event like this:
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
switch (buttonView.getId()){
case R.id.myCheckBoxName_in_XML_layout:
if(isChecked == true) {
Toast.makeText(this, "Checked", Toast.LENGTH_SHORT).show();
} else{
Toast.makeText(this, "Unchecked", Toast.LENGTH_SHORT).show();
}
break;
}
}