I have a list view that uses different layout sheets for different rows. Each sheet has different variables on them. So, when I want to implement the click listener for my list I need to know which type of row I am clicking on so that I can try to access to the correct values. For example:
list.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
//do this for layout A
//......
// do that for layout B
//......
}
});
How can I access to the layout information and the corresponding values ?
Make sure that you have a variable in your activity where you've kept the data with which you've populated the adapter.
Then, based on the position variable, you'll be able to get the exact row which was clicked. Then based on the row, you'll be able to figure out what type of row it is, right? :)
you can use the method:
public abstract int getItemViewType (int position) of your custom adapter.
Related
I have a GridView adapter displaying a grid of Buttons. Now I want to set up an OnClickListener for my buttons but of course they don't have their own R.id I can access as they are added to the grid via the adapter, rather than a layout.xml.
I tried to use OnItemClickListener as follows:
m_onItemClickListener = new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int pos, long l) {
switch(pos) {
case MyConstants.POS_OF_BUTTON_1:
// Do stuff...
break;
case MyConstants.POS_OF_BUTTON_2:
// Do stuff...
break;
}
}
};
But to my understanding you can't use a clickable or focusable item with OnItemClickListener. How do I get round this? Thanks!
There are more elegant ways to do this whole thing (starting from using a RecyclerView with a GridLayoutManager instead of a GridView), but if you're looking for the quick and easy solution to use with what you already have, this is what you can do:
First of all, you should set some ID on your buttons, they don't have to come from R.id (although it would be preferable if you inflated the views from a layout, with an ID defined there, and used a ViewHolder).
Worst case, you can just define constants in your adapter for the IDs you want to use for each kind of button (e.g. static final int DELETE_BUTTON = 1;), and then set these IDs on the buttons manually, in code.
Then you can pass a simple OnClickListener (not OnItemClickListener), which handles clicks of all these different buttons in a single item, to your adapter, and make the adapter set the listener on each of these buttons, for each of the item views in the grid.
You will also need to set the position of the item as a tag on the button view itself, so that when the click happens, you can determine for which item the click happened.
Sample code as follows:
View.OnClickListener listener = new View.OnClickListener() {
#Override
public void onClick(View v) {
Object tag = v.getTag();
if (!(tag instanceof Integer)) {
// Show error message or just throw an exception.
}
int position = (Integer) tag;
// We get the item at this position, to know which one to use
Item item = adapter.getItem(position);
switch (v.getId()) {
case DELETE_BUTTON:
// Delete stuff here
break;
case EDIT_BUTTON:
// Edit stuff here
break;
...
}
}
};
adapter.setOnClickListener(listener);
Then, in the getView method of the adapter, you need to set this listener on each of the buttons and also set the position of the item as a tag on the buttons. This way, you will be able to figure out to which item the button belongs to, in the listener code above.
#Override
public View getView(int i, View view, ViewGroup viewGroup) {
...
deleteButton.setId(DELETE_BUTTON);
deleteButton.setOnClickListener(listener);
deleteButton.setTag(i);
...
}
In general, I sincerely urge you to also look into the ViewHolder pattern, and RecyclerView and GridLayoutManager when you have time. Most of this will translate there as well.
EDIT
In order to make multiple Views clickable/focusable inside a list/grid item, you need to set the descendantFocusability attribute to blocksDescendants on the root view of the item, either simply in the XML, or in code via:
viewGroup.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
I have a listview itemClickListener that should get the model instance associated with the row clicked.
I read about tags in http://developer.android.com/reference/android/view/View.html#setTag(int, java.lang.Object)
I know that listview recycles rows, so it would not be a good idea to use v.setTag(currentItem), because that would result in an earlier row being associated with a later item.
So to solve my original problem, it looks like I need to use setTag(int, object) where the body of my click handler needs to know the unique key. The documentation states to use a resource id value, but that is not unique amongst multiple rows. How do I get the model instance for the row I clicked on?
You should just be able to grab the item out of your adapter like this:
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id)
{
ListAdapter a = (ListAdapter)parent.getAdapter();
Object itemAtPosition = a.getItem(position);
}
I have a custom ListView with two TextViews both containing different values. What I want to be able to do it get the contents from one of these TextViews when an item is clicked.
This is the code I have so far:
listView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String value;
// value = (get value of TextView here)
}
});
I want to be able to assign value to the text of one of the TextView's.
Although #Sam's suggestions will work fine in most scenarios, I actually prefer using the supplied AdapterView in onItemClick(...) for this:
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Person person = (Person) parent.getItemAtPosition(position);
// ...
}
I consider this to be a slightly more fool-proof approach, as the AdapterView will take into account any header views that may potentially be added using ListView.addHeaderView(...).
For example, if your ListView contains one header, tapping on the first item supplied by the adapter will result in the position variable having a value of 1 (rather than 0, which is the default case for no headers), since the header occupies position 0. Hence, it's very easy to mistakenly retrieve the wrong data for a position and introduce an ArrayIndexOutOfBoundsException for the last list item. By retrieving the item from the AdapterView, the position is automatically correctly offset. You can of course manually correct it too, but why not use the tools provided? :)
Just FYI and FWIW.
You have a few options. I reference the code from your previous question.
You can access this data from the row's layout view:
ViewHolder holder = (ViewHolder) view.getTag();
// Now use holder.name.getText().toString() and holder.description as you please
You can access the Adapter with position:
Person person = mAdapter.getItem(position);
// Now use person.name and person.description as you please
(By the way in your Person class, name and description are public so you don't need the get methods.)
Override following method in adaterclass.
public String[] getText() {
return text;
}
I have onItemClick listener, and I'd like to use the id value. But it has the same value as position.
public void onItemClick(AdapterView<?> a, View view, int position, long id) {
DBh.something(id);
}
I'm using a custom ArrayAdapter similar to the one described here:
onItemClickListener with custom adapter and listview
I also tried to use row.setId(), but its int not long.
I am not asking why you're trying to do this (you probably have your reasons), so will just explain how to do it. As you are already implementing a custom adapter, all you need to do is override the getItemId method:
#Override
public long getItemId(int position) {
//return ID based on the position
return ...;
}
Then this value will be passed into other methods that receive item IDs. Note that if you know how to get the ID from the position, then you can just do it straight in the onItemClickListener, as the position is passed into it.
What exactly is it you want to achieve? In your adapter, you can override "getItemId(int position)", and make it return any Id that you want to give the item. But why use the id value, why not simply use the position?
I have a list of players whos name are displayed listview. and each row of listview contains button, textview and imageview. How can I get the value of textview?
If you are using Custom Adapter class to populate the listview,then in your adapter,you can use HashMap for saving key-value pair,saving position of listitem with the data into that textview.and then you can easily retrieve it on OnItemClickListener of listview.
Depending on the specifics of your implementation, I would go with one of the following approaches.
Option A.
Use setOnItemClickListener to register a click listener with the list (or if you're using a ListActivity or ListFragment simply use [onListItemClick](http://developer.android.com/reference/android/app/ListActivity.html#onListItemClick%28android.widget.ListView, android.view.View, int, long%29)). onItemClick gets passed in the View that was clicked and can be used to retrieve nested views, e.g. the TextView you're looking for.
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
TextView tv = (TextView) view.findViewById(R.id.textview);
String tvText = tv.getText();
}
}
Option B
Assuming you fill your list from some sort of data collection, you may be able to do something similar to above, but use the passed position parameter as an index to directly get the text from the objects in your collection; i.e.:
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
SomeObject so = myCollection.get(position);
String tvText = so.getTextViewText();
}
}
There are lots of more options though. I kind of like creating my own extension of ArrayAdapter to hold the models for the views of the items in the list. That way you could also call getItemAtPosition(int position) or getItem(int position) and cast the returned object to your data type.
Is it a static list or a dynamically generated one? If its a static one you can assign a different id to each textview in the xml itself, and then use FindViewById to access it. If it's not this is what you've got to do: you will obviously have one row and display it many times. So multiple textviews will have same ID. Use a for loop, inside which use FindViewById(Remember FindViewByID will only access the first element with mentioned Id, set its Id to something else, in the next iteration the next textview is selected, set its Id to something) then use these new ids to access them, thus you can access each textview