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Each SwipeCard consists of three UI components: its content view, footer view, and overlay view(s).
The content view is the card's primary view. You can include your own card template here. The content view is set assigning the content variable.
The card's footer view is set just below the card's content view. If the footer is transparent, the card's content continue past the footer view. The footer's height is modified with footerHeight. The card's footer is set by assigning the footer variable.
An overlay view is the view whose alpha value reacts to the user's dragging. The overlays are laid out above the card's footer, regardless if the footer is transparent or not.
The card's overlays are set by assigning the leftOverlay, upOverlay, rightOverlay, and downOverlay variables.
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