问题
I have found a mysterious problem that may be a bug! I have a list in my fragment. Each row has a button. List shouldn't respond to click however buttons are clickable.
In order to get which button has clicked I have created a listener and implement it in my fragment. This is the code of my adapter.
public class AddFriendsAdapter extends BaseAdapter {
public interface OnAddFriendsListener {
public void OnAddUserClicked(MutualFriends user);
}
private final String TAG = "*** AddFriendsAdapter ***";
private Context context;
private OnAddFriendsListener listener;
private LayoutInflater myInflater;
private ImageDownloader imageDownloader;
private List<MutualFriends> userList;
public AddFriendsAdapter(Context context) {
this.context = context;
myInflater = LayoutInflater.from(context);
imageDownloader = ImageDownloader.getInstance(context);
}
public void setData(List<MutualFriends> userList) {
this.userList = userList;
Log.i(TAG, "List passed to the adapter.");
}
@Override
public int getCount() {
try {
return userList.size();
} catch (Exception e) {
e.printStackTrace();
return 0;
}
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = myInflater.inflate(R.layout.list_add_friends_row, null);
holder = new ViewHolder();
Typeface font = Typeface.createFromAsset(context.getAssets(), "fonts/ITCAvantGardeStd-Demi.ttf");
holder.tvUserName = (TextView) convertView.findViewById(R.id.tvUserName);
holder.tvUserName.setTypeface(font);
holder.ivPicture = (ImageView) convertView.findViewById(R.id.ivPicture);
holder.btnAdd = (Button) convertView.findViewById(R.id.btnAdd);
holder.btnAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.e(TAG, "Item: " + position);
listener.OnAddUserClicked(userList.get(position));
}
});
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.tvUserName.setText(userList.get(position).getName());
imageDownloader.displayImage(holder.ivPicture, userList.get(position).getPhotoUrl());
return convertView;
}
public void setOnAddClickedListener(OnAddFriendsListener listener) {
this.listener = listener;
}
static class ViewHolder {
TextView tvUserName;
ImageView ivPicture;
Button btnAdd;
}
}
When I run the app, I can see my rows however since my list is long and has over 200 items when i goto middle of list and click an item then returned position is wrong (it's something like 7, sometimes 4 and etc.).
Now what is the mystery? If I active on item listener of list from my fragment and click on row then correct row position will be displayed while on that row if I click on button then wrong position will be displayed.
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Log.e(TAG, "item " + position + " clicked.");
}
});
Result in logcat:
05-09 10:22:25.228: E/AddFriendsFragment(20296): item 109 clicked.
05-09 10:22:34.453: E/*** AddFriendsAdapter ***(20296): Item: 0
Any suggestion would be appreciated. Thanks
回答1:
Because the convertView and holder will be recycled to use, move your setOnClickListener out of the if else statement:
if (convertView == null) {
convertView = myInflater.inflate(R.layout.list_add_friends_row, null);
holder = new ViewHolder();
Typeface font = Typeface.createFromAsset(context.getAssets(), "fonts/ITCAvantGardeStd-Demi.ttf");
holder.tvUserName = (TextView) convertView.findViewById(R.id.tvUserName);
holder.tvUserName.setTypeface(font);
holder.ivPicture = (ImageView) convertView.findViewById(R.id.ivPicture);
holder.btnAdd = (Button) convertView.findViewById(R.id.btnAdd);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.btnAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
Log.e(TAG, "Item: " + position);
listener.OnAddUserClicked(userList.get(position));
}
});
It is not the best solution for that,because there will be some performance issue. I suggest you create a Map for your view and create a new view for your item then just use the relative view for each view.
I think it will be a better solution with best performance:
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = myInflater.inflate(R.layout.list_add_friends_row, null);
holder = new ViewHolder();
Typeface font = Typeface.createFromAsset(context.getAssets(), "fonts/ITCAvantGardeStd-Demi.ttf");
holder.tvUserName = (TextView) convertView.findViewById(R.id.tvUserName);
holder.tvUserName.setTypeface(font);
holder.ivPicture = (ImageView) convertView.findViewById(R.id.ivPicture);
holder.btnAdd = (Button) convertView.findViewById(R.id.btnAdd);
holder.btnAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Integer pos = (Integer)v.getTag();
Log.e(TAG, "Item: " + pos);
listener.OnAddUserClicked(userList.get(pos));
}
});
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.tvUserName.setText(userList.get(position).getName());
imageDownloader.displayImage(holder.ivPicture, userList.get(position).getPhotoUrl());
holder.btnAdd.setTag(position);
return convertView;
}
You can also manage your view by yourself. Create every unique view for your item, don't recycle view.
//member various
private Map<Integer, View> myViews = new HashMap<Integer, View>();
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
ViewHolder holder;
View view = myViews.get(position);
if (view == null) {
view = myInflater.inflate(R.layout.list_add_friends_row, null);
//don't need use the holder anymore.
Typeface font = Typeface.createFromAsset(context.getAssets(), "fonts/ITCAvantGardeStd-Demi.ttf");
holder.tvUserName = (TextView) convertView.findViewById(R.id.tvUserName);
holder.tvUserName.setTypeface(font);
holder.ivPicture = (ImageView) convertView.findViewById(R.id.ivPicture);
holder.btnAdd = (Button) convertView.findViewById(R.id.btnAdd);
holder.btnAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Integer pos = (Integer)v.getTag();
Log.e(TAG, "Item: " + pos);
listener.OnAddUserClicked(userList.get(pos));
}
});
holder.tvUserName.setText(userList.get(position).getName());
imageDownloader.displayImage(holder.ivPicture,
userList.get(position).getPhotoUrl());
myViews.put(position, view);
}
return view;
}
回答2:
Did you tried doing something like this:
holder.btnAdd.setTag(Integer.valueOf(position));
And then retrieve wich row was clicked in the callback for the button, like this:
public void btnAddClickListener(View view)
{
position = (Integer)view.getTag();
Foo foo = (Foo)foos_adapter.getItem(position); //get data of row(position)
//do some
}
回答3:
Another approach I found useful (if you are using the ViewHolder pattern of course) is to set the index on a separate attribute whenever getView() is called, then inside your onClickListener you just have to reference your holder's position attribute, something like this:
@Override
public View getView(int position, View convertView, ViewGroup parent) {
final ViewHolder holder;
if(convertView == null){
convertView = View.inflate(mContext, R.layout.contact_picker_row,null);
holder = new ViewHolder();
holder.body = (RelativeLayout)convertView.findViewById(R.id.numberBody);
convertView.setTag(holder);
}else{
holder = (ViewHolder)convertView.getTag();
}
holder.position = position;
holder.body.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(mContext,"Clicked on: "+holder.position,Toast.LENGTH_LONG).show();
}
});
return convertView;
}
private class ViewHolder{
RelativeLayout body;
int position;
}
来源：https://stackoverflow.com/questions/16453379/android-list-adapter-returns-wrong-position-in-getview