I have a ListView which uses a custom adapter as shown:
private class CBAdapter extends BaseAdapter implements OnCheckedChangeListener{
Context context;
public String[] englishNames;
LayoutInflater inflater;
CheckBox[] checkBoxArray;
LinearLayout[] viewArray;
private boolean[] checked;
public CBAdapter(Context con, String[] engNames){
context=con;
englishNames=engNames;
inflater=(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
checked= new boolean[englishNames.length];
for(int i=0; i<checked.length; i++){
checked[i]=false;
//Toast.makeText(con, checked.toString(),Toast.LENGTH_SHORT).show();
}
checkBoxArray = new CheckBox[checked.length];
viewArray = new LinearLayout[checked.length];
}
public int getCount() {
return englishNames.length;
}
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
public View getView(int position, View convertView, ViewGroup parent) {
if(viewArray[position] == null){
viewArray[position]=(LinearLayout)inflater.inflate(R.layout.record_view_start,null);
TextView tv=(TextView)viewArray[position].findViewById(R.id.engName);
tv.setText(englishNames[position]);
checkBoxArray[position]=(CheckBox)viewArray[position].findViewById(R.id.checkBox1);
}
checkBoxArray[position].setChecked(checked[position]);
checkBoxArray[position].setOnCheckedChangeListener(this);
return viewArray[position];
}
public void checkAll(boolean areChecked){
for(int i=0; i<checked.length; i++){
checked[i]=areChecked;
if(checkBoxArray[i] != null)
checkBoxArray[i].setChecked(areChecked);
}
notifyDataSetChanged();
}
public void onCheckedChanged(CompoundButton cb, boolean isChecked) {
for(int i=0; i<checked.length; i++){
if(cb == checkBoxArray[i])
checked[i]=isChecked;
}
}
public boolean itemIsChecked(int i){
return checked[i];
}
}
The layouts are fairly simple so I won't post them unless anyone thinks they are relevant.
The problem is that some of the CheckBoxes are not responding. It seems to be the ones that are visible when the layout is first displayed. Any that you have to scroll down to work as expected.
Any pointers appreciated.
Your code from the answer works but is inefficient(you can actually see this, just scroll the ListView and check the Logcat to see the garbage collector doing it's work). An improved getView method which will recycle views is the one below:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LinearLayout view = (LinearLayout) convertView;
if (view == null) {
view = (LinearLayout) inflater.inflate(R.layout.record_view_start, parent, false);
}
TextView tv = (TextView) view.findViewById(R.id.engName);
tv.setText(getItem(position));
CheckBox cBox = (CheckBox) view.findViewById(R.id.checkBox1);
cBox.setTag(Integer.valueOf(position)); // set the tag so we can identify the correct row in the listener
cBox.setChecked(mChecked[position]); // set the status as we stored it
cBox.setOnCheckedChangeListener(mListener); // set the listener
return view;
}
OnCheckedChangeListener mListener = new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
mChecked[(Integer)buttonView.getTag()] = isChecked; // get the tag so we know the row and store the status
}
};
Regarding your code from your question, at first I thought it was wrong because of the way you setup the rows but I don't see why the adapter will have that behavior as you detached the row view from the list. Also, I even tested the code and it works quite well regarding CheckBoxes(but with very poor memory handling). Maybe you're doing something else that makes the adapter to not work?
Let me first say that you have thrown away one of the main benefits of using an adapter: Reusable views. Holding a hard reference to each created View holds a high risk of hitting the memory ceiling. You should be reusing convertView when it is non-null, and creating your view when convertView is null. There are many tutorials around which show you how to do this.
Views used in an adapter typically have an OnClickListener attached to them by the parent View so that you can set a OnItemClickListener on the ListView. This will supersede any touch listeners on the individual views. Try setting android:clickable="true" on the CheckBox in XML.
This may not be the most elegant or efficient solution but it works for my situation. For some reason attempting to reuse the views either from an array of views or using convertView makes every thing go wobbley and the CheckBoxes fail to respond.
The only thing that worked was creating a new View everytime getView() is called.
public View getView(final int position, View convertView, ViewGroup parent) {
LinearLayout view;
view=(LinearLayout)inflater.inflate(R.layout.record_view_start,null);
TextView tv=(TextView)view.findViewById(R.id.engName);
tv.setText(englishNames[position]);
CheckBox cBox=(CheckBox)view.findViewById(R.id.checkBox1);
cBox.setChecked(checked[position]);
cBox.setOnCheckedChangeListener(new OnCheckedChangeListener(){
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
checked[position]=isChecked;
}
});
return view;
}
Finding this solution was also hampered by the fact that I was calling a separately defined onCheckedChangedListener, that then identified which CheckBox by id, rather than having a new listener for each CheckBox.
As yet I haven't marked this as the correct answer as I'm hoping that others may have some input regarding the rather wasteful rebuilding the view every time.
Related
My objective is to convert a working spinner (populated via a cursor adapter) to have alternating backgrounds. Similar to :-
Currently I have this, where everything works fine :-
This is the relevant working code within the cursor adpater (i.e. with the plain dropdowns) :-
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
return LayoutInflater.from(context).inflate(R.layout.activity_aisle_shop_list_selector, parent, false);
}
#Override
public void bindView(View view,Context context, Cursor cursor) {
determineViewBeingProcessed(view,"BindV",-1);
TextView shopname = (TextView) view.findViewById(R.id.aaslstv01);
shopname.setText(cursor.getString(shops_shopname_offset));
}
I have tried adding an override of the getDropDownView (code as below). I get the alternating row colors as I want but the dropdown views are blank. However, if I click outside of the selector, then they get populated with data (hence how I managed to get the screen shot, shown above, of what I want). Selection sets the correct Item.
If I remove the return after inflating the layout, then the dropdown views are populated but with data from other rows (however,selection selects the correct item)
public View getDropDownView(int position, View convertview, ViewGroup parent) {
View v = convertview;
determineViewBeingProcessed(v,"GetDDV",position);
if( v == null) {
v = LayoutInflater.from(parent.getContext()).inflate(R.layout.activity_aisle_shop_list_entry, parent, false);
return v;
}
Context context = v.getContext();
TextView shopname = (TextView) v.findViewById(R.id.aasletv01);
shopname.setText(getCursor().getString(shops_shopname_offset));
if(position % 2 == 0) {
v.setBackgroundColor(ContextCompat.getColor(context,R.color.colorlistviewroweven));
} else {
v.setBackgroundColor(ContextCompat.getColor(context,R.color.colorlistviewrowodd));
}
return v;
}
The clues were they I just didn't think hard enough. The issue is with the cursor being in the wrong position because the cursor needs to be obtained via getCursor().
Additionally, the return after the inflate, is premature (this has been commented out).
Adding getCursor().moveToPosition(position); before accessing data from the cursor resolves the problem.
Alternately (perhaps more correctly, comments appreciated on whether or not one method is more correct than the other). Adding:-
Cursor cursor = getCursor();
cursor.moveToPosition(position);
and then replacing subsequent getCursor() with cursor (not mandatory) also works.
So the final code for getDropDownView method could be:-
public View getDropDownView(int position, View convertview, ViewGroup parent) {
View v = convertview;
determineViewBeingProcessed(v,"GetDDV",position);
if( v == null) {
v = LayoutInflater.from(parent.getContext()).inflate(R.layout.activity_aisle_shop_list_entry, parent, false);
//return v;
}
Context context = v.getContext();
Cursor cursor = getCursor();
cursor.moveToPosition(position);
TextView shopname = (TextView) v.findViewById(R.id.aasletv01);
shopname.setText(cursor.getString(shops_shopname_offset));
if(position % 2 == 0) {
v.setBackgroundColor(ContextCompat.getColor(context,R.color.colorlistviewroweven));
} else {
v.setBackgroundColor(ContextCompat.getColor(context,R.color.colorlistviewrowodd));
}
return v;
}
I am new to android. I have implemented custom ArrayAdapter in my Android Application using view holder.
The getView() function of my ArrayAdapter is as follows for reference:
#Override
public View getView(int position, View convertView, final ViewGroup parent) {
View row = convertView;
MyClassViewHolder myClassViewHolder;
MyClass myClass;
if(row == null) {
LayoutInflater inflater = ((Activity)mContext).getLayoutInflater();
row = inflater.inflate(resourceId, parent, false);
if(resourceId == R.layout.my_row_item) {
myClassViewHolder = new MyClassViewHolder();
myClassViewHolder.title = (EditText) row.findViewById(R.id.title);
myClassViewHolder.switch = (Switch) row.findViewById(R.id.switch);
}
} else {
myViewHolder = (MyViewHolder) row.getTag();
}
if(resourceId == R.layout.my_row_item) {
myClass = (MyClass) myClassList.get(position); //myClassList sent as parameter to constructor of adapter
if(myClassViewHolder != null && myClass != null) {
myClassViewHolder.title.setText(myClass.getTitle());
myClassViewHolder.switch.setChecked(myClass.isEnabled());
myClassViewholder.id = myClass.getId();
myClassViewHolder.switch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
//GET ID OF THE ROW ITEM HERE
}
});
}
}
}
First of all I want to associate an id which is from database to
every row item to perform actions on them. So please confirm if the
way I have done is is right or wrong.
Secondly in the above code I have a String as title and a Switch in every row
item. I want to set an onClickListener on each switch. On toggling
the switch i want to get the id of the row item which is associated as per point 1.
Thanks in advance. Please let me know if I haven't described my problem properly.
Yes your code looks fine as for second part you should make a listener on switch and then get the id form the row and do switch from one id to another.
You may need to set a tag for each row item and thus you can identify each row. Here is an example -
row.setTag(1);
and to retrive the tag -
row.getTag();
I'm creating a custom adapter and using the getView method in attempt to display a default text only ONCE. Now I'm having a problem such that when I click the first Item in the list, the default text is kept but that doesn't hold for any other items? Any suggestions?
Thanks! (My code is a bit messy as I was just trying to debug)
boolean firstTime = true;
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if (firstTime) {
firstTime = false;
TextView firstView = new TextView(ForgotPasswordActivity.this);
firstView.setText("Please select School");
return firstView;
}
TextView view = new TextView(ForgotPasswordActivity.this);
view.setText("Hello");
return view;
}
You must play with the getCount function :
#Override
public int getCount() {
return super.getCount() -1; // This makes the trick;
}
this trick will not show last item that you've added inside your spinner(so when you finish adding your text inside the spinner, add the text that will not be shown in the spinner, and by that it will be show as a default value before clicking the spinner).
Good luck
I'm not exactly sure what your trying to do but you could force the top row to always show the select message by checking if the position is 0. Also notice in the code below that I'm reusing the convertView if it is not null. It's faster to reuse the convertView if it is available than to recreate a new view every time.
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView == null) {
convertView = new TextView(ForgotPasswordActivity.this);
}
if(position == 0) {
convertView.setText("Please select School");
} else {
convertView.setText("Hello");
}
return convertView;
}
Also remember that by forcing position zero to show the select message you are not showing the actual data in the adapter at position 0. Make sure this is what you want to do or insert a dummy piece of data in the first position of the backing data array.
I have a simple array of Strings that I was displaying in a horizontal ListView with an ArrayAdapter. What I'm looking to do is: when the user selects an item from the ListView, make that item not clickable and change the background color of that item. Perhaps like a "grayed-out" look to it. I was looking into creating a custom Adapter and overriding the isEnabled(int position) method but I don't know how I would go about this. Any advice, suggestions, or help will be greatly appreciated thanks!
I was looking into creating a custom Adapter and overriding the isEnabled(int position) method but I don't know how I would go about this.
This is quite easy to do. I recommend a SparseBooleanArray to track the enabled items for efficiency:
public class MyAdapter extends ArrayAdapter<String> {
private SparseBooleanArray enabledItems = new SparseBooleanArray();
public MyAdapter(Context context, int textViewResourceId, List<String> objects) {
super(context, textViewResourceId, objects);
}
#Override
public boolean areAllItemsEnabled() {
return false;
}
#Override
public boolean isEnabled(int position) {
return enabledItems.get(position, true);
}
public void toggleItem(int position) {
boolean state = enabledItems.get(position, true);
enabledItems.put(position, !state);
}
}
The AutoComplete feature of Eclipse did must of the work, but here are some quick notes:
You must override areAllItemsEnabled() along with isEnabled()
I designed toggle() to be used by an onItemClickListener() you only need to call adapter.toggle(position)
If you want to change the row's appearance (more than what enabling and disabling does by default) simply override getView(). Don't forget to cover both cases:
public View getView(int position, View convertView, ViewGroup parent) {
convertView = super.getView(position, convertView, parent);
if(!isEnabled(position)) {
/* change to disabled appearance */
}
else {
/* restore default appearance */
}
return convertView;
}
Hope that helps!
pass position to adapter class when you click on list item
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id)
{
adapter.setSelectedIndex(position);
}
add method of setSelectedIndex to adapter class
public void setSelectedIndex(int ind)
{
selectedIndex = ind;
notifyDataSetChanged();
}
Now check the postion of this listview if same then enable and disable value in getView me method
if(selectedIndex!= -1 && position == selectedIndex)
{
holder.tv.setBackgroundColor(Color.BLACK);
}
else
{
holder.tv.setBackgroundColor(selectedColor);
}
holder.tv.setText("" + (position + 1) + " " + testList.get(position).getTestText());
Reference from here
Use setEnabled(bool) property:
yourlistview.setEnabled(false);
Not sure whether it will work or not
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
// your code
view.setBackgroundColor(Color.BLUE);
view.setEnabled(false);
}
So I had my listview working perfectly then I decided to add a context menu. As soon as I did that whenever I normal clicked an item in my listview, the entire list gets inverted on the first click. Subsequent clicks do nothing to the order, but when the first item is de-selected again the list returns to normal. When I take out the context menu logic that I added, the list view problem does not go away.
I've attached a debugger and the elements in my list adapter are never reordered, and the ListView itself is never set to reverse with .setStackFromBottom()
Here is my onClick listener registered to handle the click events of the list view items:
public void onClick(View v) {
ViewHolder holder = (ViewHolder) v.getTag();
CheckBox b = holder.box;
Boolean check = b.isChecked();
b.setChecked(!check);
if (!check) {
mChecked.add(holder.fu);
if (mChecked.size() == 1) {
buttonLayout.setVisibility(View.VISIBLE);
}
} else {
mChecked.remove(holder.fu);
if (mChecked.size() == 0) {
buttonLayout.setVisibility(View.GONE);
}
}
}
The viewholder class just holds references to objects I use in the listview for optimizations. I cannot figure out why this is causing my list to invert when displayed, I've tried moving the listener to a different view in the layout, I've tried re-writing the listener, nothing seems to work! Any advice would be appreciated.
Edit: here is the code for the view holder
/** Class to provide a holder for ListViews. Used for optimization */
private class ViewHolder {
TextView date;
TextView gallons;
TextView cost;
TextView cpg;
TextView mpg;
CheckBox box;
FillUp fu;
}
as well as the adapter:
public class FillUpAdapter extends BaseAdapter {
ArrayList<FillUp> mElements;
ArrayList<FillUp> mChecked;
Context mContext;
public FillUpAdapter(Context c, ArrayList<FillUp> data) {
mContext = c;
mElements = data;
mChecked = new ArrayList<FillUp>();
}
public void clearChecked() {
mChecked.clear();
}
public ArrayList<FillUp> getChecked() {
return mChecked;
}
public boolean remove(FillUp f) {
mChecked.remove(f);
return mElements.remove(f);
}
#Override
public int getCount() {
return mElements.size();
}
#Override
public Object getItem(int arg0) {
return mElements.get(arg0);
}
#Override
public long getItemId(int arg0) {
return mElements.get(arg0).getId();
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LinearLayout layout;
ViewHolder holder;
if (convertView != null) {
layout = (LinearLayout) convertView;
holder = (ViewHolder) layout.getTag();
} else {
layout = (LinearLayout) LayoutInflater.from(mContext).inflate(
R.layout.fillup_list_item, parent, false);
holder = new ViewHolder();
holder.cost = (TextView) layout
.findViewById(R.id.fillUpListTotalValue);
holder.cpg = (TextView) layout
.findViewById(R.id.fillUpListCostPerGal);
holder.gallons = (TextView) layout
.findViewById(R.id.fillUpListGalValue);
holder.mpg = (TextView) layout
.findViewById(R.id.fillUpMPGText);
holder.date = (TextView) layout
.findViewById(R.id.fillUpListDate);
holder.box = (CheckBox) layout
.findViewById(R.id.fillUpListCheckBox);
holder.fu = (FillUp) getItem(position);
layout.setTag(holder);
}
holder.date.setText(holder.fu.getDate());
holder.gallons.setText(holder.fu.getGallonsText());
holder.cpg.setText(holder.fu.getCostText());
holder.cost.setText(holder.fu.getTotalText());
holder.mpg.setText(String.format("%03.1f MPG",holder.fu.getMPG()));
if (convertView != null) {
holder.box.setChecked(mChecked.contains(holder.fu));
}
layout.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
ViewHolder holder = (ViewHolder) v.getTag();
CheckBox b = holder.box;
Boolean check = b.isChecked();
b.setChecked(!check);
if (!check) {
mChecked.add(holder.fu);
if (mChecked.size() == 1) {
buttonLayout.setVisibility(View.VISIBLE);
}
} else {
mChecked.remove(holder.fu);
if (mChecked.size() == 0) {
buttonLayout.setVisibility(View.GONE);
}
}
}
});
return layout;
}
}
UPDATE:
Ok, so I've narrowed it down to the visibility change on the buttonLayout view, which is a linear layout of buttons on the bottom of the Activity's layout, underneath the ListView. Whenever I change that view's visibility to View.VISIBLE (which happens when the first item is checked) the list's order is reversed. The order is restored when the view's visibility is set to View.GONE
I have no idea what would cause that though :(
After narrowing the scope a bit more, I discovered the problem was not the changing of the visibility of my button bar, but actually the passing around of FillUp objects in holder.fu of my ViewHolder class. By changing that to instead reference the adapter's getItem(position) method, everything seemed to work out. Quite an odd bug, since the adapter itself was not having the order of the elements changed, but passing around a reference to the object made it very unhappy.
If your listview background color changes when you click on it, I think it is about your theme. Just play with the cache color parameters of your listview, here is an example:
<ListView
android:layout_width="fill_parent"
android:id="#android:id/list"
android:scrollingCache="true"
android:persistentDrawingCache="all"
android:cacheColorHint="#0000"
android:layout_height="wrap_content"
android:fastScrollEnabled="true"
android:stackFromBottom="true"
android:smoothScrollbar="true"
android:paddingTop="115dip">
</ListView>