Develop Reference

(Android GridView) CheckBox of the first item not work when I recycled convertView

I deleted almost all code in my project to find a hiding bug. There was a GridView that containing a frame layout, and the layout contained CheckBox. But I couldn't check the first check box.(others worked)
Finally (I think) I found an answer. But this is so weird. When I deleted lines for recycling convertView, the bug was gone. I changed from :
if(convertView == null) {
layout = (FrameLayout)View.inflate(maincon, R.layout.taste_brand, null);
} else {
layout = (FrameLayout) convertView;
}
to FrameLayout layout = (FrameLayout)View.inflate(maincon, R.layout.taste_brand, null);.
I really have no idea of this stuation. I attach rest codes.
TasteGridAdapter.java:
public class TasteGridAdapter extends BaseAdapter {
Context maincon;
public TasteGridAdapter(Context context) {
maincon = context;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
FrameLayout layout;
if(convertView == null) {
layout = (FrameLayout)View.inflate(maincon, R.layout.taste_brand, null);
} else {
layout = (FrameLayout) convertView;
}
layout.setLayoutParams(new GridView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.MATCH_PARENT));
return layout;
}
#Override
public int getCount() {
return 3;
}
#Override
public Object getItem(int position) {
return position;
}
#Override
public long getItemId(int position) {
return position;
}
}
onCreate of the activity :
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.taste);
TasteGridAdapter adapter = new TasteGridAdapter(this);
GridView grid = (GridView) findViewById(R.id.taste_grid);
grid.setAdapter(adapter);
}
taste.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<GridView
android:layout_weight="1"
android:id="#+id/taste_grid"
android:layout_width="match_parent"
android:layout_height="0dip"
android:columnWidth="87dip"
android:gravity="center"
android:horizontalSpacing="4dip"
android:numColumns="auto_fit"
android:padding="2dip"
android:stretchMode="columnWidth"
android:verticalSpacing="4dip" />
</LinearLayout>
taste_brand.xml:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="87dp"
android:layout_height="58dp">
<CheckBox
android:id="#+id/taste_brand_check"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</FrameLayout>

I encountered similar problem with first item in GridView. To resolve issue, remove 'new' keyword, and change existing views LayoutParams like that:
LayoutParams lp = layout.getLayoutParams();
lp.height = someHeight;
...do something with these LayoutParams. This hack resolves my issues. Conclusion, try to avoid creation of new LayoutParams object through "new".

layout.setLayoutParams(new GridView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.MATCH_PARENT));
put this line in this condition,
if(convertView == null) {
}
I was faced same problem, but i try this and its work for me. I hope it also work for you.

What you're experiencing has to do with the way Android recycles views in ListView, GridView, etc. You mention that your first checkbox is uncheckable, while your others remain working. I think you'll notice that the others only appear to work properly, since you haven't handled the recycling properly.
The reason your line
FrameLayout layout = (FrameLayout)View.inflate(maincon, R.layout.taste_brand, null);
seems to fix the problem is because this now inflates the views again each time they are used. I'll admit, when I started with this, re-inflating the views seemed to be the best solution; it entirely defeats the purpose of recycling, however, and you lose all the performance benefits otherwise gained.
So now to fix your problem:
First, I highly recommend using the ViewHolder pattern in conjunction with your BaseAdapter. More information on that can be found here.
Second, you should probably create a boolean array to match all the items in your GridView, and use it to determine whether or not an item should be clicked. Set the value of the corresponding boolean inside your checkbox listener and use that value inside getView(..) to check or uncheck that particular box.
An overall better solution might be to use an array (or list) of models inside your adapter class, each of these containing a boolean field accessible through isChecked and setChecked(boolean). Again, you would use this inside your getView(..) to display the views properly and change the value inside your checkbox OnCheckedChangeListener.
Hope that helps.

As jonstaff says, it's to do with View recycling.
If you're using a custom Adapter class for your GridView View binding, try modifying its getView() method to always instantiate a new View like:
public View getView(int position, View convertView, ViewGroup parent){
SomeView v = new SomeView(context); // <--- here
...
return v;
}
Instead of the typical:
public View getView(int position, View convertView, ViewGroup parent){
SomeView v;
if (convertView == null)
v = new SomeView (context);
else
v= (SomeView)convertView;
...
return v;
}
This may affect performance, but it solved my problem for a small GridView of Buttons.

Double AddView on adapter

I have made linear layout and add view on it, however, the view appear twice, I dont know why it happen.Can anyone fix it??
I have problem about the adapter and I look few time and I find no strange here. But I delete the statement of addView it will not appear any View I have added before.
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
if(convertView == null)
{
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
// inflater.inflate(R.layout. parent,false);
convertView = inflater.inflate(R.layout.exerciseui_item,parent,false);
}
Exercise question = exercises.get(position);
TextView question_view = (TextView) convertView.findViewById(R.id.exercise_question);
String question_test = question.getOrder() + " " + question.getText() ;
question_view.setText(question_test);
int answer_num = question.getAnswer().size();
LinearLayout linear = (LinearLayout) convertView.findViewById(R.id.exercise_answer);
ExerciseAnswer answer = question.getAnswer().get(0);
int answer_order = answer.getOrder();
String answer_text = answer.getText();
String answer_final = answer_order + " " + answer_text;
TextView answer_view = new TextView(linear.getContext());
answer_view.setPadding(20, 5, 5, 5);
answer_view.setTextSize(30);
answer_view.setText(answer_final);
linear.addView(answer_view);
return convertView;
}
The following is the xml of the exerciseui_item
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:id="#+id/exercise_answer" >
<TextView
android:id="#+id/exercise_question"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="13dp"
></TextView>
</LinearLayout>

It sounds like view re-cycling might be behind this. Your adapter is responsible for creating the view of each item in the data set (that is the purpose of the getView method). Android, in order to conserve resources, will re-cycle views. That is why the getView method is passed a View. If the passed-in view is non-null, that means it has already been used to display data in this list.
Thus it is the responsibility of the adapter, to "clean up" the view. In your case, that means that you have to account for the fact that you may have already dynamically added the TextView element to this view (in a previous getView call). Failure to "clean up" your view means that each time a view is re-cycled, your method will be adding yet another TextView to the layout.
In your case, I would suggest searching the LinearLayout for the answer TextEdit. (Give this TextEdit an id so that you can find it by using findViewById()). If it already exists, then you do not need to add it.
An other approach would be to include the 2nd TextEdit right in your XML layout. It is not clear to me why this needs to be added dynamically.

How use ArrayAdapter<T> with complex Layout?

This is the first time I need to use the ArrayAdapter<T> to show a multi-item Row-Layout. After a lot of successful work with different adapters this one is driving me crazy.
getView(..., position, ...) always returns 0-7[EDIT] so I never see elements in my ArrayList that are on position >= 7[/EDIT]. I know, this is the visible position, but how do I select the correct object in the ArrayList?
EDIT: Currently I only get the first 8 elements out of my array because position only comes in from 0-7 - even on a 50 element ArrayList. I don't see a way to position within the ArrayList without a "real" position.
The docs say the following - but I don't get it. Did somebody successfully implement an ArrayAdapter<T> with a complex layout? What do the doc mean and how should I implement it?
If you want to use a more complex
layout, use the constructors that also
takes a field id. That field id should
reference a TextView in the larger
layout resource. However the TextView
is referenced, it will be filled with
the toString() of each object in the
array. You can add lists or arrays of
custom objects. Override the
toString() method of your objects to
determine what text will be displayed
for the item in the list. To use
something other than TextViews for the
array display, for instance,
ImageViews, or to have some of data
besides toString() results fill the
views, override getView(int, View,
ViewGroup) to return the type of view
you want.
Many thanks in advance
hjw
Here's the code so far:
public class HappyAdapter extends ArrayAdapter<Happy> {
static class ViewHolder {
private ImageView imageView;
private TextView textViewBottom;
private TextView textViewTop;
}
private ArrayList<Happy> arrayListHappy;
private DrawableCache drawableCache = DrawableCache.getInstance();
private int layout;
#Override
public int getCount() {
return arrayListHappy.size();
}
#Override
public View getView(int position, View contentView, ViewGroup viewGroup) {
// position always 0-7
View view = null;
ViewHolder viewHolder = null;
if (contentView == null) {
LayoutInflater layoutInflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = layoutInflater.inflate(layout, null);
if (view != null) {
viewHolder = new ViewHolder();
viewHolder.imageView = (ImageView) view.findViewById(R.id.happyactivity_row_image_left);
viewHolder.textViewBottom = (TextView) view.findViewById(R.id.happyactivity_row_text_bottom);
viewHolder.textViewTop = (TextView) view.findViewById(R.id.happyactivity_row_text_top);
view.setTag(viewHolder);
}
} else {
view = contentView;
viewHolder = (ViewHolder) contentView.getTag();
}
if (viewHolder != null) {
Happy happy = arrayListHappy.get(position);
if (happy != null) {
viewHolder.imageView.setUrl(happy.getImageThumbnail());
drawableCache.fetchDrawable(happy.getImageThumbnail(), viewHolder.imageView);
viewHolder.textViewBottom.setText(String.valueOf(position));
viewHolder.textViewTop.setText(String.valueOf(viewHolder.position));
}
}
return view;
}
public HappyAdapter(Context context, int layout, ArrayList<Happy> arrayListHappy) {
super(context, layout, arrayListHappy);
this.arrayListHappy = arrayListHappy;
this.layout = layout;
}
}
This is part of the Row-Layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:orientation="horizontal" >
<ImageView
android:id="#+id/happyactivity_row_image_left"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_width="fill_parent" />
<TextView
style="#style/TextViewStandard"
android:id="#+id/happyactivity_row_text_top"
android:layout_weight="1" />
<TextView
style="#style/TextViewStandard"
android:id="#+id/happyactivity_row_text_bottom"
android:layout_weight="1" />
</LinearLayout>
</LinearLayout>

I can't add comments yet so have to answer. As others have noted it isn't really clear what's not working. However, you are only seeing positions 0-7 being inflated as this is the only portion of the list that is currently visible, as you noted yourself. Other rows (with higher position numbers) won't be inflated until you scroll down the list.
Although it uses the BaseAdapter class, rather than ArrayAdapter that you are using, you could look at List14.java in the ApiDemos sample code (ApiDemos/src/com/example/android/apis/view/List14.java) as the principle is the same. When using ArrayAdapter though, you don't need to override all the methods that this sample code does (just getView).

Custom list adapter repeats entries

I am trying to create a ListView that will be populated with the entries from an array.
So this is my item layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="60dip" >
<ImageView android:id="#+id/list_item_image"
android:layout_height="wrap_content"
android:padding="2dip"
android:layout_gravity="center_vertical|center_horizontal"
android:layout_width="50dip"/>
<TextView android:id="#+id/list_item"
android:layout_height="fill_parent"
android:textSize="25sp"
android:layout_width="fill_parent"
android:ellipsize="marquee"
android:gravity="center_vertical"
android:padding="5dip" >
</TextView>
</LinearLayout>
I tried changing the layout_height of the LinearLayout but I ran into some problems. If I keep the height at wrap_content, my list is displayed with the correct entries -- Item 1, Item 2, Item 3, and so on until Item 12. However if I change the height to 60dip, the entries repeat after the sixth entry (I get Item 1, Item 2, Item 3, Item 4, Item 5, Item 6, Item 1, Item 2, Item 3...). If I keep on making it larger, the entries repeat more frequently.
This is a snippet from the ListAdapter where I set the list entries:
public View getView(int position, View convertView, ViewGroup parent) {
LinearLayout layout;
if (convertView == null){
layout = (LinearLayout) LayoutInflater.from(mContext).inflate(R.layout.items_list_item, parent, false);
TextView title = (TextView) layout.findViewById(R.id.list_item);
title.setText(menuItems[position]);
ImageView icon = (ImageView) layout.findViewById(R.id.list_item_image);
int logo = getResources().getIdentifier(menuIcons[position], "drawable", getPackageName());
icon.setImageResource(logo);
} else {
layout = (LinearLayout) convertView;
}
return layout;
}
Anybody else encountered this problem? I do not understand what is going on since I thought it should be straight-forward grabbing from the array.
EDIT: included the whole of my getView() method. Pardon the ugly way of getting the icons, I haven't figured it out yet,

You didn't post enough code, but in your Adapter's getView(...) try to make use of the convertView.
public View getView(int position, View convertView, ViewGroup parent){
if(convertView == null){
convertView = mInflater.inflate(R.layout.my_listitem_row, parent, false);
}
//...fill the TextViews on your layout
return convertView;
}
Fetching the icons should be as easy as
icon.setImageResource(R.drawable.my_icon); //the res/drawable folder has the my_icon.png file

From the little snippet of code I'm going to guess that it's something to do with the views being reused and the text not getting updated. I'm not certain though without seeing all of the code for the ListAdapter.
Take a look at this session from Google I/O 2010 for loads of really helpful information on how to use ListViews (and by extension adapters). It contains lots of tips and advice on the best way of using them. If you have time watch the video, if not the slides are avaliable.
Good Luck :)

Android: How to hide a ListView Item

How can you hide an item in a ListView or at least set its height to zero?
I have tried setting the visibility of the View to GONE but it still maintains the item's space (height).

Ressurecting an old question, but I just had this issue where I wanted to hide list items temporarily based upon criteria outside of the list data. What I ended up doing was creating a "null item" layout in xml and returned that based upon my criteria instead of the convert view in getView()...
instead of returning the convertView, I returned my null_item...
return inflater.inflate(R.layout.null_item, null);
null_item.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</LinearLayout>

if you want to hide the item like this:
convertView.setLayoutParams(new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,1));
convertView.setVisibility(View.GONE);
can't be AbsListView.LayoutParams(-1,0);
if convertview are reused you should add this below to set it height back:
if(convertView.getVisibility() == View.GONE) {
convertView.setLayoutParams(new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, AbsListView.LayoutParams.WRAP_CONTENT));
convertView.setVisibility(View.VISIBLE);
}

When it comes to ListView, to make it efficient, we use ViewHolder pattern. The way to use ViewHolder Pattern and R.layout.row_null of the following xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</LinearLayout>
is to use with getViewTypeCount() and getItemViewType(int position) as follow.
#Override
public int getViewTypeCount() {
return 2;
}
#Override
public int getItemViewType(int position) {
return (hideStatusCheck(position)) ? 1 : 0;
}
#Override
public View getView(int pos, View convertView, ViewGroup parent) {
View rowView = convertView;
if (hideStatusCheck(pos)) {
if (rowView == null || rowView.getTag() != null) {
LayoutInflater inflater = mActivity.getLayoutInflater();
rowView = inflater.inflate(R.layout.row_null, parent, false);
}
} else {
if (rowView == null) {
rowView = inflateNormalView(parent);
} else if (rowView.getTag() == null) {
rowView = inflateNormalView(parent);
} else {
ViewHolder holderToCheck = (ViewHolder) rowView.getTag();
Integer storedPos = (Integer) holderToCheck.getTag(POSITION);
if (storedPos == null || storedPos != pos)
rowView = inflateNormalView(parent);
}
ViewHolder holder = (ViewHolder) rowView.getTag();
holder.setTag(POSITION,pos);
/*
Populate data
*/
return rowView;
}
private View inflateNormalView(ViewGroup parent) {
View rowView;
LayoutInflater inflater = mActivity.getLayoutInflater();
rowView = inflater.inflate(R.layout.normal_item, parent, false);
ViewHolder viewHolder = new ViewHolder();
assert rowView != null;
/* Initiate normal findViewById thing*/
rowView.setTag(viewHolder);
return rowView;
}
We do the checking of the item's View type and if it meets the hide check, it will return 1, otherwise 0. The ListView knows that there will be 2 types of View from getViewTypeCount. Now, the getView will return the approriate View depending on the hideStatusCheck. To make a robust ListView, we want to use the ViewHolder pattern. We don't need to use ViewHolder when it is hidden. We simply inflate the R.layout.row_null and return it. We will use the ViewHolder for the R.layout.normal_item. Here is the tricky part assuming the hiding check is not static. The first check of rowView==null is standard. The second check of rowView.getTag()==null is to see if the View is coming back to normal
from hiding. The third check in the last else clause is to check if the ViewHolder retained in the tag is the right ViewHolder. If these conditions are met, we always inflate the view again. Yes, it is true that, the ViewHolder pattern is not used throughout but it uses to certain extends. It is better than nothing.

I did some tinkering with a drag and drop list from here. When an item is popped out of the list to be moved around the cell space it occupied has it's height set to 1px (see line 238) so it appears "gone". I couldn't find a way to handle this better as setting height to 0 fails as does visibility GONE.
That said, If you really want to get rid of a row less temporarily, it might be a good idea to change the backing of the Adapter and call notifyDataSetChanged() on it.

I have look at source code. And there is only one way to hide item without notifyDataSetChanged(). You must set visibility GONE for all inner views and remove background image and paddings for item's view.
Note: Row with such invisible element will be selectable.
P.S: This is very usefull for ExpandableListView if you want to hide group view it self.

add to your ListView object:
android:dividerHeight="0px"
android:divider="#FFFFFF"
Divider color doesn't matter
only setting dividerHeight doesn't work
This does remove the divider though...

I think I have a much easier / safer solution: you just have to "embed" your item in a Layout, and change the visibility of this parent layout.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<!-- Embed ListView Item into a "parent" Layout -->
<LinearLayout
android:id="#+id/parentLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<!-- This is the normal content of your ListView Item -->
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="World" />
</LinearLayout>
</LinearLayout>
Then in your code just do:
public View getView(int position, View view, ViewGroup parent) {
if (view == null) {
LayoutInflater li = mActivity.getLayoutInflater();
view = li.inflate(R.layout.my_listview_item, null);
}
LinearLayout parentLayout = (LinearLayout) view.findViewById(R.id.parentLayout);
if (shouldDisplayItem(position)) {
parentLayout.setVisibility(View.VISIBLE);
} else {
parentLayout.setVisibility(View.GONE);
}
return view;
}
This way you always use/reuse the same item, and just hide/show it.

To Hide whole raw from listview in android:-
RelativeLayout parentLayout = (RelativeLayout) view.findViewById(R.id.relative);
if (productPojoList.get(position).getSERSERVICETYPE().toString().equals("Group|Promotional")){
view.setLayoutParams(new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,1));
view.setVisibility(View.GONE);
} else {
if(view.getVisibility() == View.GONE) {
view.setLayoutParams(new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, AbsListView.LayoutParams.WRAP_CONTENT));
view.setVisibility(View.VISIBLE);
}
}