CheckBox changes value twice
I have an Android ListView
whose items have a checkbox.
The checkbox is checked by default. Once unchecked it should be removed from the list.
The problem is that onCheckedChanged
is being fired twice: when I tap the checkbox to uncheck it (with isChecked
false
) and after I remove the item (with isChecked
true
).
This is the relevant code of my ArrayAdapte开发者_如何学Gor:
public View getView(final int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.item, parent, false);
holder = new ViewHolder();
holder.check = (CheckBox) convertView.findViewById(R.id.check);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
final Object item = this.getItem(position);
holder.check.setOnCheckedChangeListener(new CheckBox.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (!isChecked) {
remove(item); // This somehow calls onCheckedChanged again
}
}
});
return convertView;
}
What am I doing wrong?
I had a similar issue and just resolved it properly without having to avoid using the intended OnCheckedChangeListener
.
Problem Code
holder.someCheckBox.setChecked(false);
holder.someCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
...
}
});
Note I set the check status before I set the listener, this was to prevent the listener from firing on creation.
But, the listener started firing the on-check event exactly twice only after the adapter was forced to be re-created or through use of notifyDataSetChanged
.
Solution
Clear the listener before setting the check state, even during creation here.
holder.someCheckBox.setOnCheckedChangeListener(null);
holder.someCheckBox.setChecked(false);
holder.someCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
...
}
});
Now any residual listeners will not be fired when setting the initial value of the checkbox.
I encountered the same problem, it seems to be an Android bug this twice execution of onCheckChanged method.
My solution: implement onClickListener
, instead of onCheckedChangedListener
.
Something like this:
private final class CheckUpdateListener implements OnClickListener {
private Group parent;
private boolean isChecked;
private CheckUpdateListener(Group parent) {
this.parent = parent;
}
@Override
public void onClick(View box) {
this.isChecked = !parent.isChecked();
parent.setChecked(isChecked);
notifyDataSetChanged();
}
}
I encounter the same issue.
After some research i found out that there is a similar behaviour in RadioGroup for the setCheckChangeListener.
Tagging messes things up, seems like a bug.
My workaround was setting the tag to null at the end of the listener It worked for me.
private OnCheckedChangeListener checkBoxitemClickListener = new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if(isChecked)
{
//do smth
}else
{
//do smth
}
buttonView.setTag(null);
}
};
If you need to update your ListView after, don't forget to call "notifyDataSetChanged" on your adapter.
Cheers
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