I would like to have a listView that the first list item will have a red background and the second will have black.Is that possible?And if yes,how will i create the custom list adapter?
thanks!!
|Black item|
|Red item|
|Black item|
|Red item|
|Black item|
etc.
You should Override getView in your arrayadapter. One of the parameters passed into this method is a position. So you can just do the position % 2 to determine if the row is even or odd. Depending on what you want to do you can change you can inflate two totally different layouts there.
When you have the public View getView(int position, View convertView, ViewGroup parent) method make it apply different style for each position %2 == 0. This way you can easily make those items differ from each other :)
I hope this helped.
here's the getView from my latest project's adapter. I've simplified it to highlight a couple of things: 1. that you can use whatever criteria you like to decide what kind of view will be returned, and 2. that you can use LayoutInflater.inflate to get any kind of view at all, whatever the case may be.
public View getView(final int position, View convertView, ViewGroup parent)
{
View v;
int n = itemList.get(position);
if (n < 0)
{
v = inflator.inflate(R.layout.layout1, null);
}
else if (n > 0)
{
v = inflator.inflate(R.layout.layout2, null);
}
else
v = inflator.inflate(R.layout.layout3, null);
return v;
}
Related
This is my listView
I want to add a February header on top of 2016-02-02 and January in 2016-01-31. Is it possible?
Yes, you can do this by returning a different view in your getView() method in your adapter class. In your master list, that you pass to your adapter, you can add a divider item, a String or however you are holding all this data, I assume a custom class, that you know is meant to show a Month title. You can do a quick check in your getView() method and return a different view that displays the month..
In your getView() method, you can do this...
#Override
public View getView(final int position, View convertView, ViewGroup parent){
LayoutInflater mInflator = LayoutInflater.from(getContext());
View customView = mInflator.inflate(R.layout.times_layout, parent, false);
Time temp = getItem(position);
//Check to see if the time is supposed to be a header
//This is where you check to see if it meant to be a section header
if(temp.getDate.equals("HEADER")){
//Header, return section view instead of normal view
View sectionHeader = mInflator.inflate(R.layout.layout_list_divider, parent, false);
TextView txt_Section = (TextView) sectionHeader.findViewById(R.id.txt_Header);
sectionHeader.setClickable(false);
return sectionHeader;
}
//Normal View... do what you would do normally
return customView;
}
I hope this helps! Let me know.. it worked for me
In android It's called ExpandableListView
You can try this tutorial:
http://www.androidhive.info/2013/07/android-expandable-list-view-tutorial/
It also has a sample to download.
I'm Noob at Java Android.
I searched more about my question and I found that I can use
listView.getFirstVisiblePosition();
To get my first visible position. How can I implement a new Background Resource only to my first visible position?
I tried to do that by far.
View get = lv.getFirstVisiblePosition()
get.setBackgroundResource(R.drawable.newconversation);
Thanks.
There is a method in your adapter which controls your list items views
#Override
public View getView(int position, View convertView, ViewGroup parent) {
You can just use this condition :
if(position == 0)
//set your background
After convertView has been inflated
getFirstVisiblePosition() returns an Integer position. You want to get the view at that position.
Try
View view = list.getChildAt(list.getFirstVisiblePosition());
Then set your background on the view.
I have a question.
how to make highlight selection of row in List View by different colors? but I want to do it correct with list selectors.
Please provide some simple for few colors
thank you
You may set up colors in your Adapter.getView() method:
public View getView(int position, View convertView, ViewGroup parent) {
View result = ...
// check convertView, inflate new layout, bla-bla-bla
if (position % 2 == 0) {
result.setBackgroundResource(R.drawable.even);
} else {
result.setBackgroundResource(R.drawable.odd);
}
return result;
}
Android GridView is quite interesting, it reuses the child views. The ones scrolled up comes back from bottom. So there is no method from GridView to get the child view by its position. But I really need to get view by its position and do some work on it. So to do that, I created an SparseArray and put views by their position in it from getView of BaseAdapter.
SparseArray<View> ViewArray = new SparseArray<View>();
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (view == null)
view = li.inflate(layoutID, null);
ViewArray.put(position, view);
}
Now, I can get all visible views by their position. Everything works perfect as it should but in some devices, the first child view(position 0) is not same as the one in array. I logged the getView and found that for position 0, getView got called many times and each time array was set with different view. I have no idea why GridView is calling getView for position 0 many times and that happens only on few devices. Any solution ?
After reading source of getPositionForView, I have wrote this method in own GridView, works perfect by API 18
public View GetViewByPosition(int position) {
int firstPosition = this.getFirstVisiblePosition();
int lastPosition = this.getLastVisiblePosition();
if ((position < firstPosition) || (position > lastPosition))
return null;
return this.getChildAt(position - firstPosition);
}
You can't reach the views directly because of the recycling. The view at position 0 may be re-used for the position 10, so you can't be sure of the data present in a specific view.
The way to go is to use the underlying data. If you need to modify data at position 10, then do it in the List or array under your adapter and call notifyDataSetChanged() on the adapter.
if you need to have different views for different data subtypes, you can override the two following method in your adapter: getItemViewType() and getViewTypeCount()
Then, in getView() you can 1) decide which layout to inflate 2) know the type of view recycled using getItemViewType()
You can find an example here:
https://stackoverflow.com/a/5301093/990616
There was an issue reported for this. Here is the link. This issue has been closed as WorkingAsIntended. Wish means we can expect the GridView to call getView() on pos 0 multiple times.
My work around is as follow:
public class GridAdapter extends BaseAdapter {
...
int previouslyDisplayedPosition = -1;
...
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if(previouslyDisplayedPosition != position) {
....
previouslyDisplayedPosition = position;
}
return convertedView;
}
What I am trying to do here is returning the same 'convertView' if same pos is called again and again. There by preventing any logic within getView() (eg setting image view etc)to be executed again and again.
I have a row in a listview that I need to change its layout dynamically. In my array adapter I have the following (simplified) code
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView == null) {
convertView = inflater.inflate(R.layout.default);
}
...
if(condition) {
View view = inflater.inflate(R.layout.new);
...
return view; // doesn't work
}
return convertView;
}
My actual listview is actually pretty complex and I am also using the getViewType for the two different layouts. But the above code should be enough to make my point that the new layout won't display correctly when I want to switch layout dynamically.
My question is, how can I refresh the convertView, or trigger a reload of the adapter/listview to the point that the convertViews will be cleared? I've tried calling notifyDataSetChanged, or calling the listview invalidateViews() but they all didn't worked. My last resort seems to restart the whole activity but I don't think this is an elegant solution.