public interface ListModel<T>
Known subtypesContactsModel, DefaultListModel, FilterProxyListModel, MultipleSelectionListModel
Represents the data structure of the list, thus allowing a list to represent any potential data source by referencing different implementations of this interface, notice that we strongly discourage usage of lists.. E.g. a list model can be implemented in such a way that it retrieves data directly from storage (although caching would be recommended).
It is the responsibility of the list to notify observers (specifically the view
com.codename1.ui.List of any changes to its state (items removed/added/changed etc.)
thus the data would get updated on the view.
class GRMMModel implements ListModel> {
@Override
public Map getItemAt(int index) {
int idx = index % 7;
switch(idx) {
case 0:
return createListEntry("A Game of Thrones " + index, "1996");
case 1:
return createListEntry("A Clash Of Kings " + index, "1998");
case 2:
return createListEntry("A Storm Of Swords " + index, "2000");
case 3:
return createListEntry("A Feast For Crows " + index, "2005");
case 4:
return createListEntry("A Dance With Dragons " + index, "2011");
case 5:
return createListEntry("The Winds of Winter " + index, "2016 (please, please, please)");
default:
return createListEntry("A Dream of Spring " + index, "Ugh");
}
}
@Override
public int getSize() {
return 1000000;
}
@Override
public int getSelectedIndex() {
return 0;
}
@Override
public void setSelectedIndex(int index) {
}
@Override
public void addDataChangedListener(DataChangedListener l) {
}
@Override
public void removeDataChangedListener(DataChangedListener l) {
}
@Override
public void addSelectionListener(SelectionListener l) {
}
@Override
public void removeSelectionListener(SelectionListener l) {
}
@Override
public void addItem(Map item) {
}
@Override
public void removeItem(int index) {
}
}
A ListModel can be used in conjunction with an com.codename1.components.ImageViewer
to fetch images dynamically into the view:
Form hi = new Form("ImageViewer", new BorderLayout());
final EncodedImage placeholder = EncodedImage.createFromImage(
FontImage.createMaterial(FontImage.MATERIAL_SYNC, s).
scaled(300, 300), false);
class ImageList implements ListModel {
private int selection;
private String[] imageURLs = {
"http://awoiaf.westeros.org/images/thumb/9/93/AGameOfThrones.jpg/300px-AGameOfThrones.jpg",
"http://awoiaf.westeros.org/images/thumb/3/39/AClashOfKings.jpg/300px-AClashOfKings.jpg",
"http://awoiaf.westeros.org/images/thumb/2/24/AStormOfSwords.jpg/300px-AStormOfSwords.jpg",
"http://awoiaf.westeros.org/images/thumb/a/a3/AFeastForCrows.jpg/300px-AFeastForCrows.jpg",
"http://awoiaf.westeros.org/images/7/79/ADanceWithDragons.jpg"
};
private Image[] images;
private EventDispatcher listeners = new EventDispatcher();
public ImageList() {
this.images = new EncodedImage[imageURLs.length];
}
public Image getItemAt(final int index) {
if(images[index] == null) {
images[index] = placeholder;
Util.downloadUrlToStorageInBackground(imageURLs[index], "list" + index, (e) -> {
try {
images[index] = EncodedImage.create(Storage.getInstance().createInputStream("list" + index));
listeners.fireDataChangeEvent(index, DataChangedListener.CHANGED);
} catch(IOException err) {
err.printStackTrace();
}
});
}
return images[index];
}
public int getSize() {
return imageURLs.length;
}
public int getSelectedIndex() {
return selection;
}
public void setSelectedIndex(int index) {
selection = index;
}
public void addDataChangedListener(DataChangedListener l) {
listeners.addListener(l);
}
public void removeDataChangedListener(DataChangedListener l) {
listeners.removeListener(l);
}
public void addSelectionListener(SelectionListener l) {
}
public void removeSelectionListener(SelectionListener l) {
}
public void addItem(Image item) {
}
public void removeItem(int index) {
}
};
ImageList imodel = new ImageList();
ImageViewer iv = new ImageViewer(imodel.getItemAt(0));
iv.setImageList(imodel);
hi.add(BorderLayout.CENTER, iv);
Methods
Method details
getItemAt
public abstract T getItemAt(int index)Returns the item at the given offset
Parameters
indexint- an index into this list
Returns
the item at the specified index
getSize
public abstract int getSize()Returns the number of items in the list
Returns
the number of items in the list
getSelectedIndex
public abstract int getSelectedIndex()Returns the selected list offset
Returns
the selected list index
setSelectedIndex
public abstract void setSelectedIndex(int index)Sets the selected list offset can be set to -1 to clear selection
Parameters
indexint- an index into this list
addDataChangedListener
public abstract void addDataChangedListener(DataChangedListener l)Invoked to indicate interest in future change events
Parameters
lDataChangedListener- a data changed listener
removeDataChangedListener
public abstract void removeDataChangedListener(DataChangedListener l)Invoked to indicate no further interest in future change events
Parameters
lDataChangedListener- a data changed listener
addSelectionListener
public abstract void addSelectionListener(SelectionListener l)Invoked to indicate interest in future selection events
Parameters
lSelectionListener- a selection listener
removeSelectionListener
public abstract void removeSelectionListener(SelectionListener l)Invoked to indicate no further interest in future selection events
Parameters
lSelectionListener- a selection listener
addItem
public abstract void addItem(T item)Adds the specified item to the end of this list.
An optional operation for mutable lists, it can throw an unsupported operation
exception if a list model is not mutable.
Parameters
itemT- the item to be added
removeItem
public abstract void removeItem(int index)Removes the item at the specified position in this list.
Parameters
indexint- the index of the item to removed