axmol/core/ui/UIListView.h

/****************************************************************************
Copyright (c) 2013-2016 Chukong Technologies Inc.
Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

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#ifndef __UILISTVIEW_H__
#define __UILISTVIEW_H__

#include "ui/UIScrollView.h"
#include "ui/GUIExport.h"

/**
 * @addtogroup ui
 * @{
 */
NS_CC_BEGIN

namespace ui
{

/**
 *@brief ListView is a view group that displays a list of scrollable items.
 *The list items are inserted to the list by using `addChild` or  `insertDefaultItem`.
 * @warning The list item in ListView doesn't support cell reuse at the moment, if you have a large amount of data need
 *to be displayed, use  `TableView` instead. ListView is a subclass of  `ScrollView`, so it shares many features of
 *ScrollView.
 */
class CC_GUI_DLL ListView : public ScrollView
{

    DECLARE_CLASS_GUI_INFO
public:
    /**
     * Gravity for docking elements in ListView.
     */
    enum class Gravity
    {
        LEFT,
        RIGHT,
        CENTER_HORIZONTAL,
        TOP,
        BOTTOM,
        CENTER_VERTICAL
    };

    /**
     * ListView element item click event.
     */
    enum class EventType
    {
        ON_SELECTED_ITEM_START,
        ON_SELECTED_ITEM_END
    };

    /**
     * ListView supports magnetic scroll.
     * With CENTER type, ListView tries to align its items in center of current view.
     * With BOTH_END type, ListView tries to align its items in left or right end if it is horizontal, top or bottom in
     * vertical. The aligning side (left or right, top or bottom) is determined by user's scroll direction.
     */
    enum class MagneticType
    {
        NONE,
        CENTER,
        BOTH_END,
        LEFT,
        RIGHT,
        TOP,
        BOTTOM,
    };

    /**
     * ListView item click callback.
     */
    typedef std::function<void(Ref*, EventType)> ccListViewCallback;

    /**
     * Default constructor
     * @js ctor
     * @lua new
     */
    ListView();

    /**
     * Default destructor
     * @js NA
     * @lua NA
     */
    virtual ~ListView();

    /**
     * Create an empty ListView.
     *@return A ListView instance.
     */
    static ListView* create();

    /**
     * Set an item model for listview.
     *
     * When calling `pushBackDefaultItem`, the model will be used as a blueprint and new model copy will be inserted
     * into ListView.
     * @param model  Model in `Widget*`.
     */
    void setItemModel(Widget* model);

    /**
     * Insert a default item(create by a cloned model) at the end of the listview.
     */
    void pushBackDefaultItem();

    /**
     * Insert a default item(create by cloning model) into listview at a give index.
     *@param index  An index in ssize_t.
     */
    void insertDefaultItem(ssize_t index);

    /**
     * Insert a  custom item into the end of ListView.
     *@param item An item in `Widget*`.
     */
    void pushBackCustomItem(Widget* item);

    /**
     * @brief Insert a custom widget into ListView at a given index.
     *
     * @param item A widget pointer to be inserted.
     * @param index A given index in ssize_t.
     */
    void insertCustomItem(Widget* item, ssize_t index);

    /**
     *  Removes the last item of ListView.
     */
    void removeLastItem();

    /**
     * Remove an item at given index.
     *
     * @param index A given index in ssize_t.
     */
    void removeItem(ssize_t index);

    /**
     * @brief Remove all items in current ListView.
     *

     */
    void removeAllItems();

    /**
     * Return an item at a given index.
     *
     * @param index A given index in ssize_t.
     * @return A widget instance.
     */
    Widget* getItem(ssize_t index) const;

    /**
     * Return all items in a ListView.
     *@returns A vector of widget pointers.
     */
    Vector<Widget*>& getItems();

    /**
     * Return the index of specified widget.
     *
     * @param item  A widget pointer.
     * @return The index of a given widget in ListView.
     */
    ssize_t getIndex(Widget* item) const;

    /**
     * Set the gravity of ListView.
     * @see `ListViewGravity`
     */
    void setGravity(Gravity gravity);

    /**
     * Set magnetic type of ListView.
     * @see `MagneticType`
     */
    void setMagneticType(MagneticType magneticType);

    /**
     * Get magnetic type of ListView.
     */
    MagneticType getMagneticType() const;

    /**
     * Set magnetic allowed out of boundary.
     */
    void setMagneticAllowedOutOfBoundary(bool magneticAllowedOutOfBoundary);

    /**
     * Query whether the magnetic out of boundary is allowed.
     */
    bool getMagneticAllowedOutOfBoundary() const;

    /**
     * Set the margin between each item in ListView.
     *
     * @param margin A margin in float.
     */
    void setItemsMargin(float margin);

    /**
     * @brief Query margin between each item in ListView.
     *

     * @return A margin in float.
     */
    float getItemsMargin() const;

    /**
     * Change padding with left, top, right, and bottom padding.
     * @param l Left padding in float.
     * @param t Top margin in float.
     * @param r Right margin in float.
     * @param b Bottom margin in float.
     */
    void setPadding(float l, float t, float r, float b);

    /**
     * Change padding with left padding
     * @param l Left padding in float.
     */
    void setLeftPadding(float l);

    /**
     * Change padding with top padding
     * @param t Top padding in float
     */
    void setTopPadding(float t);

    /**
     * Change padding with right padding
     * @param r Right padding in float
     */
    void setRightPadding(float r);

    /**
     * Change padding with bottom padding
     * @param b Bottom padding in float
     */
    void setBottomPadding(float b);

    /**
     * Get the left padding in ListView
     * @return Left padding in float
     */
    float getLeftPadding() const;

    /**
     * Get the top padding in ListView
     * @return Top padding in float
     */
    float getTopPadding() const;

    /**
     * Get the right padding in ListView
     * @return Right padding in float
     */
    float getRightPadding() const;

    /**
     * Get the bottom padding in ListView
     * @return Bottom padding in float
     */
    float getBottomPadding() const;

    /**
     * Set the time in seconds to scroll between items.
     * Subsequent calls of function 'scrollToItem', will take 'time' seconds for scrolling.
     * @param time The seconds needed to scroll between two items. 'time' must be >= 0
     * @see scrollToItem(ssize_t, const Vec2&, const Vec2&)
     */
    void setScrollDuration(float time);

    /**
     * Get the time in seconds to scroll between items.
     * @return The time in seconds to scroll between items
     * @see setScrollDuration(float)
     */
    float getScrollDuration() const;

    // override methods
    virtual void doLayout() override;
    virtual void requestDoLayout() override;
    virtual void addChild(Node* child) override;
    virtual void addChild(Node* child, int localZOrder) override;
    virtual void addChild(Node* child, int zOrder, int tag) override;
    virtual void addChild(Node* child, int zOrder, std::string_view name) override;
    virtual void removeAllChildren() override;
    virtual void removeAllChildrenWithCleanup(bool cleanup) override;
    virtual void removeChild(Node* child, bool cleanup = true) override;

    /**
     * @brief Query the closest item to a specific position in inner container.
     *
     * @param targetPosition Specifies the target position in inner container's coordinates.
     * @param itemAnchorPoint Specifies an anchor point of each item for position to calculate distance.
     * @return An item instance if list view is not empty. Otherwise, returns null.
     */
    Widget* getClosestItemToPosition(const Vec2& targetPosition, const Vec2& itemAnchorPoint) const;

    /**
     * @brief Query the closest item to a specific position in current view.
     * For instance, to find the item in the center of view, call
     * 'getClosestItemToPositionInCurrentView(Vec2::ANCHOR_MIDDLE, Vec2::ANCHOR_MIDDLE)'.
     *
     * @param positionRatioInView Specifies the target position with ratio in list view's content size.
     * @param itemAnchorPoint Specifies an anchor point of each item for position to calculate distance.
     * @return An item instance if list view is not empty. Otherwise, returns null.
     */
    Widget* getClosestItemToPositionInCurrentView(const Vec2& positionRatioInView, const Vec2& itemAnchorPoint) const;

    /**
     * @brief Query the center item
     * @return An item instance.
     */
    Widget* getCenterItemInCurrentView() const;

    /**
     * @brief Query the leftmost item in horizontal list
     * @return An item instance.
     */
    Widget* getLeftmostItemInCurrentView() const;

    /**
     * @brief Query the rightmost item in horizontal list
     * @return An item instance.
     */
    Widget* getRightmostItemInCurrentView() const;

    /**
     * @brief Query the topmost item in horizontal list
     * @return An item instance.
     */
    Widget* getTopmostItemInCurrentView() const;

    /**
     * @brief Query the bottommost item in horizontal list
     * @return An item instance.
     */
    Widget* getBottommostItemInCurrentView() const;

    /**
     * Override functions
     */
    virtual void jumpToBottom() override;
    virtual void jumpToTop() override;
    virtual void jumpToLeft() override;
    virtual void jumpToRight() override;
    virtual void jumpToTopLeft() override;
    virtual void jumpToTopRight() override;
    virtual void jumpToBottomLeft() override;
    virtual void jumpToBottomRight() override;
    virtual void jumpToPercentVertical(float percent) override;
    virtual void jumpToPercentHorizontal(float percent) override;
    virtual void jumpToPercentBothDirection(const Vec2& percent) override;

    /**
     * @brief Jump to specific item
     * @param itemIndex Specifies the item's index
     * @param positionRatioInView Specifies the position with ratio in list view's content size.
     * @param itemAnchorPoint Specifies an anchor point of each item for position to calculate distance.
     */
    void jumpToItem(ssize_t itemIndex, const Vec2& positionRatioInView, const Vec2& itemAnchorPoint);

    /**
     * @brief Scroll to specific item
     * @param positionRatioInView Specifies the position with ratio in list view's content size.
     * @param itemAnchorPoint Specifies an anchor point of each item for position to calculate distance.
     * @param timeInSec Scroll time
     */
    void scrollToItem(ssize_t itemIndex, const Vec2& positionRatioInView, const Vec2& itemAnchorPoint);
    void scrollToItem(ssize_t itemIndex, const Vec2& positionRatioInView, const Vec2& itemAnchorPoint, float timeInSec);

    /**
     * @brief Query current selected widget's index.
     *

     * @return An index of a selected item.
     */
    ssize_t getCurSelectedIndex() const;

    /**
     * @brief Set current selected widget's index and call TouchEventType::ENDED event.
     * @param itemIndex A index of a selected item.
     */
    void setCurSelectedIndex(int itemIndex);

    /**
     * Add an event click callback to ListView, then one item of Listview is clicked, the callback will be called.
     *@param callback A callback function with type of `ccListViewCallback`.
     */
    void addEventListener(const ccListViewCallback& callback);
    using ScrollView::addEventListener;

    /**
     * Changes scroll direction of scrollview.
     *
     *  Direction Direction::VERTICAL means vertical scroll, Direction::HORIZONTAL means horizontal scroll.
     * @param dir Set the list view's scroll direction.
     */
    virtual void setDirection(Direction dir) override;

    virtual std::string getDescription() const override;

    CC_CONSTRUCTOR_ACCESS : virtual bool init() override;

protected:
    virtual void handleReleaseLogic(Touch* touch) override;

    virtual void onItemListChanged();

    virtual void remedyLayoutParameter(Widget* item);
    void updateInnerContainerSize();
    void remedyVerticalLayoutParameter(LinearLayoutParameter* layoutParameter, ssize_t itemIndex);
    void remedyHorizontalLayoutParameter(LinearLayoutParameter* layoutParameter, ssize_t itemIndex);

    virtual void onSizeChanged() override;
    virtual Widget* createCloneInstance() override;
    virtual void copySpecialProperties(Widget* model) override;
    virtual void copyClonedWidgetChildren(Widget* model) override;
    void selectedItemEvent(TouchEventType event);
    virtual void interceptTouchEvent(Widget::TouchEventType event, Widget* sender, Touch* touch) override;

    virtual Vec2 getHowMuchOutOfBoundary(const Vec2& addition = Vec2::ZERO) override;

    virtual void startAttenuatingAutoScroll(const Vec2& deltaMove, const Vec2& initialVelocity) override;

    void startMagneticScroll();
    Vec2 calculateItemDestination(const Vec2& positionRatioInView, Widget* item, const Vec2& itemAnchorPoint);

protected:
    Widget* _model;

    Vector<Widget*> _items;

    Gravity _gravity;

    MagneticType _magneticType;
    bool _magneticAllowedOutOfBoundary;

    float _itemsMargin;

    float _leftPadding;
    float _topPadding;
    float _rightPadding;
    float _bottomPadding;

    float _scrollTime;

    ssize_t _curSelectedIndex;

    bool _innerContainerDoLayoutDirty;
    ccListViewCallback _eventCallback;
};

}  // namespace ui
NS_CC_END
// end of ui group
/// @}

#endif /* defined(__ListView__) */