Unity中的UGUI源码解析之事件系统(8)-输入模块(中)
接上一篇文章, 继续介绍输入模块.
Unity中主要处理的是指针事件, 也就是在2d平面上跟踪指针设备输入坐标的的事件, 这一类事件有鼠标事件, 触摸事件等.
PointerInputModule
Unity将使用抽象类PointerInputModule定义指针输入的基本信息和基本函数, 由其子类StandaloneInputModule来具体实现.
相关类
TouchPhase
TouchPhase用来描述触摸阶段.
Began
: 开始触摸Moved
: 移动Stationary
: 触摸, 静止Ended
: 抬起Canceled
: 取消(通过导航事件)
MouseButtonEventData
MouseButtonEventData用来封装鼠标按钮事件数据, 封装按钮事件数据和状态, 提供状态函数.
public class MouseButtonEventData
{
/// 前面文章介绍过的按钮状态枚举, 表示每个按钮在当前帧的状态
public PointerEventData.FramePressState buttonState;
/// 指针事件数据
public PointerEventData buttonData;
/// 当前帧是否被按下
public bool PressedThisFrame()
{
return buttonState == PointerEventData.FramePressState.Pressed || buttonState == PointerEventData.FramePressState.PressedAndReleased;
}
/// 当前帧是否被放开
public bool ReleasedThisFrame()
{
return buttonState == PointerEventData.FramePressState.Released || buttonState == PointerEventData.FramePressState.PressedAndReleased;
}
}
ButtonState
ButtonState用来封装按钮状态.
protected class ButtonState
{
/// 前面文章介绍过的按钮枚举
private PointerEventData.InputButton m_Button = PointerEventData.InputButton.Left;
/// 鼠标事件数据封装体
private MouseButtonEventData m_EventData;
public MouseButtonEventData eventData
{
get { return m_EventData; }
set { m_EventData = value; }
}
public PointerEventData.InputButton button
{
get { return m_Button; }
set { m_Button = value; }
}
}
MouseState
MouseState用来封装鼠标状态. 主要跟踪所有的鼠标按钮, 提供设置和获取按钮状态的函数, 还有提供查询按下和放开的函数.
protected class MouseState
{
private List<ButtonState> m_TrackedButtons = new List<ButtonState>();
public bool AnyPressesThisFrame()
{
for (int i = 0; i < m_TrackedButtons.Count; i++)
{
if (m_TrackedButtons[i].eventData.PressedThisFrame())
return true;
}
return false;
}
public bool AnyReleasesThisFrame()
{
for (int i = 0; i < m_TrackedButtons.Count; i++)
{
if (m_TrackedButtons[i].eventData.ReleasedThisFrame())
return true;
}
return false;
}
/// 获取按钮状态, 如果没有则新建空白按钮状态
public ButtonState GetButtonState(PointerEventData.InputButton button)
{
ButtonState tracked = null;
for (int i = 0; i < m_TrackedButtons.Count; i++)
{
if (m_TrackedButtons[i].button == button)
{
tracked = m_TrackedButtons[i];
break;
}
}
if (tracked == null)
{
tracked = new ButtonState { button = button, eventData = new MouseButtonEventData() };
m_TrackedButtons.Add(tracked);
}
return tracked;
}
public void SetButtonState(PointerEventData.InputButton button, PointerEventData.FramePressState stateForMouseButton, PointerEventData data)
{
var toModify = GetButtonState(button);
toModify.eventData.buttonState = stateForMouseButton;
toModify.eventData.buttonData = data;
}
}
字段和属性
public abstract class PointerInputModule : BaseInputModule
{
// --------------------
// 鼠标按键标识, 都是负数, 触摸的标识都是正数
/// 左键
public const int kMouseLeftId = -1;
/// 右键
public const int kMouseRightId = -2;
/// 中键
public const int kMouseMiddleId = -3;
// --------------------
/// 缓存的指针事件数据
protected Dictionary<int, PointerEventData> m_PointerData = new Dictionary<int, PointerEventData>();
/// 鼠标状态
private readonly MouseState m_MouseState = new MouseState();
}
公开函数
PointerInputModule的公开函数比较少, 一个是检测指针是给定id的指针是否位于某个对象区域, 一个是ToString.
public override bool IsPointerOverGameObject(int pointerId)
{
// 通过获取指针的事件数据, 判断事件数据
var lastPointer = GetLastPointerEventData(pointerId);
if (lastPointer != null)
return lastPointer.pointerEnter != null;
return false;
}
public override string ToString()
{
var sb = new StringBuilder("<b>Pointer Input Module of type: </b>" + GetType());
sb.AppendLine();
foreach (var pointer in m_PointerData)
{
if (pointer.Value == null)
continue;
sb.AppendLine("<B>Pointer:</b> " + pointer.Key);
sb.AppendLine(pointer.Value.ToString());
}
return sb.ToString();
}
私有函数
// 判断是否开始拖拽, 可以使用EventSystem组件上的pixelDragThreshold
private static bool ShouldStartDrag(Vector2 pressPos, Vector2 currentPos, float threshold, bool useDragThreshold)
{
if (!useDragThreshold)
return true;
return (pressPos - currentPos).sqrMagnitude >= threshold * threshold;
}
受保护函数
// 获取指定指针id的事件数据
protected bool GetPointerData(int id, out PointerEventData data, bool create)
{
if (!m_PointerData.TryGetValue(id, out data) && create)
{
data = new PointerEventData(eventSystem)
{
pointerId = id,
};
m_PointerData.Add(id, data);
return true;
}
return false;
}
// 删除指定指针id的事件数据
protected void RemovePointerData(PointerEventData data)
{
m_PointerData.Remove(data.pointerId);
}
// 获取指定指针id的事件数据, 不新建
protected PointerEventData GetLastPointerEventData(int id)
{
PointerEventData data;
GetPointerData(id, out data, false);
return data;
}
// 获取触摸类型的事件数据
protected PointerEventData GetTouchPointerEventData(Touch input, out bool pressed, out bool released)
{
// 初始化指针数据
PointerEventData pointerData;
var created = GetPointerData(input.fingerId, out pointerData, true);
pointerData.Reset();
// 新建或者触摸开始阶段, 判断为按下
pressed = created || (input.phase == TouchPhase.Began);
// 取消或者触摸结束, 判断为按下且抬起
released = (input.phase == TouchPhase.Canceled) || (input.phase == TouchPhase.Ended);
// 如果是新建, 记录输入位置以便记录相对位移
if (created)
pointerData.position = input.position;
if (pressed) // 如果是按下, 清空相对位移
pointerData.delta = Vector2.zero;
else // 否则, 记录相对位移
pointerData.delta = input.position - pointerData.position;
// 记录输入位置
pointerData.position = input.position;
// 初始化按钮标识
pointerData.button = PointerEventData.InputButton.Left;
// 所有投射器投射此指针数据, 记录结果
eventSystem.RaycastAll(pointerData, m_RaycastResultCache);
// 查找第一个满足要求的被击中的对象
var raycast = FindFirstRaycast(m_RaycastResultCache);
// 记录当前集中对象
pointerData.pointerCurrentRaycast = raycast;
// 清空结果缓存
m_RaycastResultCache.Clear();
return pointerData;
}
// 拷贝事件数据, "@"是为了避免与关键字冲突(虽然这里的两个变量都不是关键字), 本身不是变量名的一部分
protected void CopyFromTo(PointerEventData @from, PointerEventData @to)
{
@to.position = @from.position;
@to.delta = @from.delta;
@to.scrollDelta = @from.scrollDelta;
@to.pointerCurrentRaycast = @from.pointerCurrentRaycast;
@to.pointerEnter = @from.pointerEnter;
}
// 获取鼠标按钮当前帧的状态
protected PointerEventData.FramePressState StateForMouseButton(int buttonId)
{
var pressed = input.GetMouseButtonDown(buttonId);
var released = input.GetMouseButtonUp(buttonId);
if (pressed && released)
return PointerEventData.FramePressState.PressedAndReleased;
if (pressed)
return PointerEventData.FramePressState.Pressed;
if (released)
return PointerEventData.FramePressState.Released;
return PointerEventData.FramePressState.NotChanged;
}
protected virtual MouseState GetMousePointerEventData()
{
return GetMousePointerEventData(0);
}
// 获取鼠标指针事件数据, 这里的参数没有用, 设计者是想用来给子类重写的
protected virtual MouseState GetMousePointerEventData(int id)
{
// 初始化指针数据, 默认左键
PointerEventData leftData;
var created = GetPointerData(kMouseLeftId, out leftData, true);
leftData.Reset();
// 如果新建的, 记录鼠标位置, 用于后面计算相对位移
if (created)
leftData.position = input.mousePosition;
Vector2 pos = input.mousePosition;
if (Cursor.lockState == CursorLockMode.Locked)
{ // 如果光标被锁定, 那么忽略位置信息
// We don't want to do ANY cursor-based interaction when the mouse is locked
leftData.position = new Vector2(-1.0f, -1.0f);
leftData.delta = Vector2.zero;
}
else
{ // 计算相对位移和记录鼠标位置
leftData.delta = pos - leftData.position;
leftData.position = pos;
}
// 记录鼠标滚动量
leftData.scrollDelta = input.mouseScrollDelta;
// 标记为左键
leftData.button = PointerEventData.InputButton.Left;
// 获取投射结果
eventSystem.RaycastAll(leftData, m_RaycastResultCache);
// 查找第一个满足要求的被击中的对象
var raycast = FindFirstRaycast(m_RaycastResultCache);
// 记录当前集中对象
leftData.pointerCurrentRaycast = raycast;
// 清空结果缓存
m_RaycastResultCache.Clear();
// --------------------------------------------------------------
// -- 复制左键数据到右键和中键
PointerEventData rightData;
GetPointerData(kMouseRightId, out rightData, true);
CopyFromTo(leftData, rightData);
rightData.button = PointerEventData.InputButton.Right;
PointerEventData middleData;
GetPointerData(kMouseMiddleId, out middleData, true);
CopyFromTo(leftData, middleData);
middleData.button = PointerEventData.InputButton.Middle;
// --------------------------------------------------------------
// 分别查询和设置左中右建的当前按钮状态
m_MouseState.SetButtonState(PointerEventData.InputButton.Left, StateForMouseButton(0), leftData);
m_MouseState.SetButtonState(PointerEventData.InputButton.Right, StateForMouseButton(1), rightData);
m_MouseState.SetButtonState(PointerEventData.InputButton.Middle, StateForMouseButton(2), middleData);
return m_MouseState;
}
// 处理移动事件, 在移动的过程中可能会触发进入和离开事件
protected virtual void ProcessMove(PointerEventData pointerEvent)
{
// 如果光标锁定, 只处理离开事件
var targetGO = (Cursor.lockState == CursorLockMode.Locked ? null : pointerEvent.pointerCurrentRaycast.gameObject);
HandlePointerExitAndEnter(pointerEvent, targetGO);
}
// 处理拖拽事件
protected virtual void ProcessDrag(PointerEventData pointerEvent)
{
// 如果未处于移动状态, 或者光标被锁定, 或者没有被拖拽的对象则不处理拖拽
if (!pointerEvent.IsPointerMoving() ||
Cursor.lockState == CursorLockMode.Locked ||
pointerEvent.pointerDrag == null)
return;
// 如果未处理过拖拽并且允许处理, 则向被拖拽对象发送开始拖拽事件, 并记录已处理状态
if (!pointerEvent.dragging
&& ShouldStartDrag(pointerEvent.pressPosition, pointerEvent.position, eventSystem.pixelDragThreshold, pointerEvent.useDragThreshold))
{
ExecuteEvents.Execute(pointerEvent.pointerDrag, pointerEvent, ExecuteEvents.beginDragHandler);
pointerEvent.dragging = true;
}
// 处理拖拽过程中的事件
if (pointerEvent.dragging)
{
// 在处理拖拽之前, 向上一个按下对象发送抬起事件(如果两个对象不一样), 并清空事件的点击状态
// [这里是可以同时处理拖拽和点击的关键点]
if (pointerEvent.pointerPress != pointerEvent.pointerDrag)
{
ExecuteEvents.Execute(pointerEvent.pointerPress, pointerEvent, ExecuteEvents.pointerUpHandler);
// 后面在处理点击事件时无法进入
pointerEvent.eligibleForClick = false;
pointerEvent.pointerPress = null;
pointerEvent.rawPointerPress = null;
}
// 发送拖拽事件
ExecuteEvents.Execute(pointerEvent.pointerDrag, pointerEvent, ExecuteEvents.dragHandler);
}
}
// 清空所有被选中的对象, 输入模块被反激活时使用
protected void ClearSelection()
{
var baseEventData = GetBaseEventData();
foreach (var pointer in m_PointerData.Values)
{
// 向所有悬停对象发送离开事件
HandlePointerExitAndEnter(pointer, null);
}
// 清空指针事件数据
m_PointerData.Clear();
// 向当前焦点对象发送取消选择事件
eventSystem.SetSelectedGameObject(null, baseEventData);
}
// 如果选择的对象发生变化, 则向当前焦点对象发送取消选择事件
protected void DeselectIfSelectionChanged(GameObject currentOverGo, BaseEventData pointerEvent)
{
var selectHandlerGO = ExecuteEvents.GetEventHandler<ISelectHandler>(currentOverGo);
if (selectHandlerGO != eventSystem.currentSelectedGameObject)
eventSystem.SetSelectedGameObject(null, pointerEvent);
}
总结
今天详细介绍了PointerInputModule, 内容不是很多, 相比大家都能看明白.
下篇文章介绍StandaloneInputModule, 应该是事件系统的最后一篇文章了, 只是在今天内容的基础上重写和添加了少量的内容, 也不是很复杂, 应该说Unity的C#层都不是很复杂, 复杂的是Cpp层.
好了, 今天就是这样了, 希望对大家有所帮助.