使用 xlue 实现 tips

经常遇到如下的需求

鼠标hover到目标对象一定时间后，弹出tips或者窗口;

鼠标离开目标对象一定时间后，隐藏tips或者窗口;

鼠标从目标对象移动到弹出的窗口上，这种状况下不隐藏窗口;

考虑到这种需求，绘制如下的状态图：

如上图所示，将tips的状态分为hide,showing,show,hiding,enter 五个状态；

hide: tips没有显示

showing: 准备显示tips

show: 显示tips

hiding: 准备隐藏tips

enter: 鼠标进入了tips控件，这种状况下仍然显示 tips

使用上面的状态图，清晰地描述了tips可能存在的各种状态，并确定了驱动事件有哪些。理清了思路。

hide状态时：hover到目标控件会进入 showing 状态；

showing 状态时：离开目标控件会返回到 hide 状态；

进入 showing 状态后，开启一个timer，当timer结束后，如果仍然是 showing 状态，则转到 show 状态并显示tips

show 状态时：离开目标控件会进入hiding状态；

hiding 状态时：hover到目标控件会返回到 show 状态；

进入 hiding 状态后，开启一个timer，当timer结束后，如果仍然是 hiding 状态，则转到 hide 状态并隐藏tips

鼠标从目标控件移动到tips上，会使得状态从 show 转到 hiding 转到 enter, 此时tips仍然显示，当离开tips控件后，状态又转移回 hiding ，此时开启一个timer，timer结束后，同样根据是否仍然是 hiding 状态来隐藏tips

编程实现：

function AddWindowTip(tippedObj, text, callback)

    local function showTipsFunc(tippedObj, x, y)
        -- 创建tips窗口
        local hostwndId = "TipsHelper.TipsHostWnd.Instance." .. tippedObj:GetID()
        local objtreeId = "TipsHelper.TipsTree.Instance." .. tippedObj:GetID()
        local hostwndTemplateId = "TipsWndTemplate"
        local objtreeTemplateId = "TipsTreeTemplate"

        local hostwndManager = XLGetObject("Xunlei.UIEngine.HostWndManager")
        local hostwnd = hostwndManager:GetHostWnd(hostwndId)
        if hostwnd then
            local objtree = hostwnd:GetBindUIObjectTree()
            if objtree then
                hostwnd:UnbindUIObjectTree()
                local objtreeManager = XLGetObject("Xunlei.UIEngine.TreeManager")
                objtreeManager:DestroyTree(objtree)
            end
            hostwndManager:RemoveHostWnd(hostwndId)
        end
        local templateManager = XLGetObject("Xunlei.UIEngine.TemplateManager")
        local wndTemplate = templateManager:GetTemplate(hostwndTemplateId, "HostWndTemplate")
        if not wndTemplate then
            return
        end
        local hostwnd = wndTemplate:CreateInstance(hostwndId)
        if not hostwnd then
            return
        end
        local objtreeTemplate = templateManager:GetTemplate(objtreeTemplateId, "ObjectTreeTemplate")
        local objtree = objtreeTemplate:CreateInstance(objtreeId)
        if not objtree then
            return
        end
        hostwnd:BindUIObjectTree(objtree)
        hostwnd:Create()

        -- 设定text
        local rootObj = objtree:GetRootObject()
        local textObj = objtree:GetUIObject("text")
        textObj:SetText(text)
        local width, height = textObj:GetTextExtent()
        textObj:SetObjPos(4,3,width,height)
        width,height = width + 8, height + 6
        rootObj:SetObjPos(0,0,width+8,height+6)
        
        -- 移动窗口位置
        local tippedOwner = tippedObj:GetOwner()
        local tippedHostWnd = tippedOwner:GetBindHostWnd()
        local l,t,r,b = tippedObj:GetObjPos()
        local left = l+(r-l-width)/2
        local top = b
        left,top = tippedHostWnd:HostWndPtToScreenPt(left,top)
        hostwnd:Move(left,top,width,height)
        
        return rootObj
    end
    local function hideTipsFunc(tippedObj)
        -- 销毁tips窗口
        local hostwndId = "TipsHelper.TipsHostWnd.Instance." .. tippedObj:GetID()

        local hostwndManager = XLGetObject("Xunlei.UIEngine.HostWndManager")
        local hostwnd = hostwndManager:GetHostWnd(hostwndId)
        if not hostwnd then
            return
        end
        
        local objtree = hostwnd:GetBindUIObjectTree()
        if objtree then
            hostwnd:UnbindUIObjectTree()
            local objtreeManager = XLGetObject("Xunlei.UIEngine.TreeManager")
            objtreeManager:DestroyTree(objtree)
        end
        hostwndManager:RemoveHostWnd(hostwndId)
        
        return true
    end
    
    -- state: tip 的状态, hide隐藏,showing正在显示,show显示,hiding正在隐藏,enter进入tips中
    local state = "hide"    -- 使用状态控制 tips 在各个状态间转换
    tippedObj:AttachListener("OnMouseMove", true, function(obj, x, y, flags)
        if state == "hide" then
            state = "showing"
            local timerMgr = XLGetObject("Xunlei.UIEngine.TimerManager")
            timerMgr:SetOnceTimer(function()
                if state == "showing" then
                    local tipsObj = showTipsFunc(obj, x, y)
                    if tipsObj then
                        state = "show"
                        
                        --[[ 这段代码，使得移动到弹出的窗口上时，窗口不会被隐藏
                        tipsObj:AttachListener("OnMouseMove", true, function()
                            if state == "hiding" then
                                state = "enter"
                            end
                        end)
                        tipsObj:AttachListener("OnMouseLeave", true, function()
                            if state == "enter" then
                                state = "hiding"
                                local timerMgr = XLGetObject("Xunlei.UIEngine.TimerManager")
                                timerMgr:SetOnceTimer(function()
                                    if state == "hiding" then
                                        if hideTipsFunc(obj) then
                                            state = "hide"
                                            if callback and type(callback) == "function" then
                                                callback(tippedObj, false)
                                            end
                                        end
                                    end
                                end, 300)
                            end
                        end)
                        --]]
                        
                        if callback and type(callback) == "function" then
                            callback(obj, true)
                        end
                    end
                end
            end, 300)
        elseif state == "hiding" then
            state = "show"
        end
    end)
    tippedObj:AttachListener("OnMouseLeave", true, function(obj, x, y, flags)
        if state == "show" then
            state = "hiding"
            local timerMgr = XLGetObject("Xunlei.UIEngine.TimerManager")
            timerMgr:SetOnceTimer(function()
                if state == "hiding" then
                    if hideTipsFunc(obj) then
                        state = "hide"
                        if callback and type(callback) == "function" then
                            callback(tippedObj, false)
                        end
                    end
                end
            end, 300)
        elseif state == "showing" then
            state = "hide"
        end
    end)
    
end