java.lang.ClassCastException,尝试使用相同的自定义适配器有两个活动
问题描述:
我有两个活动,NewContact.java
和ViewContact.java
,我想使用相同的custom adapter
,因为两个活动非常相似。java.lang.ClassCastException,尝试使用相同的自定义适配器有两个活动
但我收到以下错误,我的应用程序崩溃:
AndroidRuntime: FATAL EXCEPTION: main
java.lang.ClassCastException: com.example.chris.tutorialspoint.ViewContact cannot be cast to com.example.chris.tutorialspoint.NewContact
我和科目AndroidRuntime: FATAL EXCEPTION:
,java.lang.ClassCastException
这里看了不少帖子,但我不知道如何调整的答案,以适应我的需求。
这里是我的适配器的getView
代码。我知道这个问题是与线:
viewHolder.check.setOnCheckedChangeListener((NewContact) _c);
viewHolder.check.setOnCheckedChangeListener((ViewContact) _c);
如果我删除,则线custom adapter
作品剩下的活动之一,但我想有工作两个活动,NewContact
和ViewContact
。
@Override
public View getView(int i, View convertView, ViewGroup viewGroup) {
System.out.println("getView number is :" + i + "convertView is : " + convertView);
//we're naming our convertView as view
// View view = convertView;
ViewHolder viewHolder = null;
if (convertView == null) {
//if there is nothing there (if it's null) inflate the view with the layout
LayoutInflater li = (LayoutInflater) _c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = li.inflate(R.layout.phone_inflate_listview, null);
viewHolder = new ViewHolder();
// So, for example, title is cast to the name id, in phone_inflate_listview,
// phone is cast to the id called no etc
viewHolder.title = (TextView) convertView.findViewById(R.id.name);
viewHolder.phone = (TextView) convertView.findViewById(R.id.no);
viewHolder.invite = (Button) convertView.findViewById(R.id.btnInvite);
viewHolder.check = (CheckBox) convertView.findViewById(R.id.checkBoxContact);
// viewHolder.check.setVisibility(View.GONE);
//remember the state of the checkbox
viewHolder.check.setOnCheckedChangeListener((NewContact) _c);
viewHolder.check.setOnCheckedChangeListener((ViewContact) _c);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
// store the holder with the view
final SelectPhoneContact data = (SelectPhoneContact) arraylist.get(i);
//in the listview for contacts, set the name
viewHolder.title.setText(data.getName());
//in the listview for contacts, set the number
viewHolder.phone.setText(data.getPhone());
////*********************
//for every phone number in the MatchingContactsAsArrayList array list...
for (int number = 0; number < MatchingContactsAsArrayList.size(); number++) {
//if a phone number is in our array of matching contacts
if (MatchingContactsAsArrayList.contains(data.getPhone()))
{
//if a matching contact, no need to show the Invite button
viewHolder.invite.setVisibility(View.GONE);
System.out.println("it's a match: phoneNumberofContact is : " + data.getPhone());
//once a matching contact is found, no need to keep looping x number of time, move onto next contact
break;
}
else {
//if not a matching contact, no need to show the check box
viewHolder.check.setVisibility(View.GONE);
}
}
viewHolder.check.setChecked(data.isSelected());
viewHolder.check.setTag(data);
// Return the completed view to render on screen
return convertView;
}
答
你并不需要强制转换Context
具体Activity
类型。该setOnCheckedChangeListener()
方法只需要一个OnCheckedChangeListener
,如果这两个类实现这个接口,你只需要一个呼叫铸Context
到OnCheckedChangeListener
。
viewHolder.check.setOnCheckedChangeListener((OnCheckedChangeListener) _c);
这可能是谨慎的做法是在构造函数中添加instanceof
检查,以确保传递Context
确实是一个OnCheckedChangeListener
,这将有故障的更快,并且让您有机会的好处也许抛出Exception
与更丰富的信息。
如果两个'Activity'类实现'OnCheckedChangeListener',那么你只需要一个'setOnCheckedChangeListener()'调用,铸造'_c'到'OnCheckedChangeListener'。 –
是的。这不好吗。请张贴的答案,我会很乐意接受。 – CHarris