UXCollectionView

UXCollectionView is the icon grid: items of a fixed size flow left to right and wrap into rows to fill the width, the layout the Finder desktop and icon browsers use. The grid arithmetic (how many columns fit, each item’s rectangle, the total content height a scroll view asks for) and the hit test are pure geometry, unit-tested without a window. Multi-selection rides UXIndexSet, the same machinery the table uses.

#use <UXKit>

Overview

UXCollectionView* grid = new UXCollectionView();
for (i32 i = (i32)0; i < docs.count(); i = i + (i32)1) {
    grid.addItem(docs.get(i), docs.nameAt(i));
}
grid.setAction(&controller.onPick);
scroll.document().addSubview(grid, UXGeom.make(0, 0, 400, 0));
scroll.setDocumentHeight(grid.contentHeightFor(400));

A plain click selects one item; a shift-click toggles it into the selection; a click in the gaps deselects everything. The action fires on selection; the handler reads it back:

void onPick(UXControl* sender) {
    UXCollectionView* g = (UXCollectionView* ?)sender;
    open(g.itemAt(g.firstSelected()).obj);
}

Conforms to

Inherits UXControl: the weak: callback action, enablement, the fire path.

Topics

Items · addItem · clear · count · itemAt Grid · setItemSize · setSpacing · setInset · columnsFor · layout · contentHeightFor · itemAtPoint Selection · selectItem · addToSelection · toggleSelection · deselectAll · isSelected · selectionCount · firstSelected

addItem

void addItem(Object* obj, u8* label)

Appends an item: your object (returned untouched at selection time) and the label drawn under its tile.

clear

void clear(void)

Empties the grid and the selection.

count

i32 count(void)

How many items the grid holds.

itemAt

UXCollectionItem* itemAt(i32 i)

The item: your obj, the label, and the laid-out frame (see UXCollectionItem).

setItemSize

void setItemSize(i16 w, i16 h)

The fixed tile size (64×64 by default).

setSpacing

void setSpacing(i16 h, i16 v)

The gaps between tiles, horizontally and vertically.

setInset

void setInset(i16 v)

The margin around the whole grid.

columnsFor

i32 columnsFor(i16 width)

How many columns fit in width, never fewer than one.

layout

void layout(i16 width)

Places every item into its row and column and computes the content height. Pure geometry; the tests call it with no window.

contentHeightFor

i32 contentHeightFor(i16 width)

The total height the laid-out grid needs at width, the value you pass to a UXScrollView’s setDocumentHeight.

itemAtPoint

i32 itemAtPoint(i16 px, i16 py)

The item under a local point, -1 in the gaps. A click between tiles deselects, as in an icon view.

selectItem

void selectItem(i32 i)

Selects this item and no other (the plain-click behaviour).

addToSelection

void addToSelection(i32 i)

Adds without clearing: the programmatic half of multi-selection.

toggleSelection

void toggleSelection(i32 i)

Flips the item in or out (the shift-click behaviour).

deselectAll

void deselectAll(void)

Clears the selection.

isSelected

bool isSelected(i32 i)

Whether the item is in the selection.

selectionCount

i32 selectionCount(void)

How many items are selected.

firstSelected

i32 firstSelected(void)

The lowest selected index, -1 when nothing is.