NGUI例子Scroll View场景中item添加点击后自动滑到终点

http://blog.csdn.net/luyuncsd123/article/details/22914497

最近在做一个项目的UI，需求是1、拖动items后当永远有一个item保存在中间位置，2、点击当前item后当前item滑动到终点。 

咱看了NGUI的Scroll View例子后发现第一个要求NGUI自带了，第二个要求没有，所以自己写了个包含这2个需求的脚本。 


把相应的脚本替换成这几个就可以了。如果碰到变量保护之类的错误的话把父类中的方法改成protected就行了。 

using UnityEngine; 
using System.Collections; 

[ExecuteInEditMode] 
public class QRCUICenterOnChild : UICenterOnChild 
{ 
    private Transform moveTarget; 

    protected QRCUIDraggablePanel mQrcDrag; 

    void OnEnable() { Recenter(null); //Recenter(); 
    } 

    void OnDragFinished(GameObject obj) 
    { 
        if (enabled) 
        { 
            //if (obj != null) 
                Recenter(obj); 
            //else 
            //    Recenter(); 
        } 
    } 

    /// <summary> 
    /// Recenter the draggable list on the center-most child. 
    /// </summary> 

    public void Recenter(GameObject obj) 
    { 
        if (mQrcDrag == null) 
        { 
            mQrcDrag = NGUITools.FindInParents<qrcuidraggablepanel>(gameObject); 

            if (mQrcDrag == null) 
            { 
                Debug.LogWarning(GetType() + " requires " + typeof(QRCUIDraggablePanel) + " on a parent object in order to work", this); 
                enabled = false; 
                return; 
            } 
            else 
            { 
                mQrcDrag.onDragFinished = OnDragFinished; 

                //if (mDrag.horizontalScrollBar != null) 
                //    mDrag.horizontalScrollBar.onDragFinished = OnDragFinished; 

                //if (mDrag.verticalScrollBar != null) 
                //    mDrag.verticalScrollBar.onDragFinished = OnDragFinished; 
            } 
        } 
        if (mQrcDrag.panel == null) return; 

        // Calculate the panel's center in world coordinates 
        Vector4 clip = mQrcDrag.panel.clipRange; 
        Transform dt = mQrcDrag.panel.cachedTransform; 
        Vector3 center = dt.localPosition; 
        center.x += clip.x; 
        center.y += clip.y; 
        center = dt.parent.TransformPoint(center); 

        // Offset this value by the momentum 
        Vector3 offsetCenter = center - mQrcDrag.currentMomentum * (mQrcDrag.momentumAmount * 0.1f); 
        mQrcDrag.currentMomentum = Vector3.zero; 

        float min = float.MaxValue; 
        Transform closest = null; 
        Transform trans = transform; 

        //Determine whether the user is to click on or drag 
        if (obj != null) 
        { 
            closest = obj.transform; 
        } 
        else { 
            closest = DetermineCloestChild(trans, offsetCenter, min, closest); 
        } 

        // Spring the panel to this calculated position 
        MoveTargetPosition(closest, dt, center); 
    } 

    /// <summary> 
    /// Determine the closest child 
    /// </summary> 
    public Transform DetermineCloestChild(Transform trans, Vector3 offsetCenter, float min, Transform closest) 
    { 
        for (int i = 0, imax = trans.childCount; i < imax; ++i) 
        { 
            Transform t = trans.GetChild(i); 
            float sqrDist = Vector3.SqrMagnitude(t.position - offsetCenter); 

            if (sqrDist < min) 
            { 
                min = sqrDist; 
                closest = t; 
            } 
        } 
        return closest; 
    } 

    /// <summary> 
    /// Spring the panel to this calculated position 
    /// </summary> 
    public void MoveTargetPosition(Transform closest, Transform dt, Vector3 center) 
    { 
        if (closest != null) 
        { 
            mCenteredObject = closest.gameObject; 

            // Figure out the difference between the chosen child and the panel's center in local coordinates 
            Vector3 cp = dt.InverseTransformPoint(closest.position); 
            Vector3 cc = dt.InverseTransformPoint(center); 
            Vector3 offset = cp - cc; 

            // Offset shouldn't occur if blocked by a zeroed-out scale 
            if (mQrcDrag.scale.x == 0f) offset.x = 0f; 
            if (mQrcDrag.scale.y == 0f) offset.y = 0f; 
            if (mQrcDrag.scale.z == 0f) offset.z = 0f; 

            // Spring the panel to this calculated position 
            SpringPanel.Begin(mQrcDrag.gameObject, dt.localPosition - offset, 8f).onFinished = OnQrcFisished; 
        } 
        else mCenteredObject = null; 
    } 


    public delegate void OnQrcMoveToTragetFisished(GameObject obj); 
    public event OnQrcMoveToTragetFisished OnQrcMoveToTragetFisishedHandler; 
    /// <summary> 
    /// After reaching the target this method will be used. 
    /// </summary> 
    public void OnQrcFisished() { 
        OnQrcMoveToTragetFisishedHandler(mCenteredObject); 
    } 

} 





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using UnityEngine;using System.Collections; 

[ExecuteInEditMode] 
[RequireComponent(typeof(UIPanel))]public class QRCUIDraggablePanel : UIDraggablePanel 
{ 

    public delegate void OnDragFinished(GameObject obj); 

    /// <summary>    /// Event callback to trigger when the drag process finished. Can be used for additional effects, such as centering on some object. 
    /// </summary> 

    public OnDragFinished onDragFinished; 


    public void Press(bool pressed, GameObject obj) 
    {        if (enabled && NGUITools.GetActive(gameObject)) 
        {            if (!pressed && mDragID == UICamera.currentTouchID) mDragID = -10; 

            mCalculatedBounds = false; 
            mShouldMove = shouldMove;            if (!mShouldMove) return; 
            mPressed = pressed; 

            if (pressed)            { 
                // Remove all momentum on press                mMomentum = Vector3.zero; 
                mScroll = 0f; 

                // Disable the spring movement                DisableSpring(); 

                // Remember the hit position 
                mLastPos = UICamera.lastHit.point; 

                // Create the plane to drag along                mPlane = new Plane(mTrans.rotation * Vector3.back, mLastPos); 
            }            else 
            {                if (restrictWithinPanel && mPanel.clipping != UIDrawCall.Clipping.None && dragEffect == DragEffect.MomentumAndSpring) 
                {                    RestrictWithinBounds(false); 
                }                if (onDragFinished != null) onDragFinished(obj); 
            }        } 
    }} 




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using UnityEngine;using System.Collections; 

[ExecuteInEditMode] 
public class QRCUIDragPanelContents : UIDragPanelContents{ 

    private Vector3 previousTouch; 

    /// <summary> 
    /// Create a plane on which we will be performing the dragging.    /// </summary> 
    protected void OnPress(bool pressed)    { 
        bool isClick = false;        Vector3 currentPos = Vector3.zero; 

        //Judge runtime platform 
        if (Application.platform == RuntimePlatform.IPhonePlayer || Application.platform == RuntimePlatform.Android)        { 
            if (Input.touchCount > 0)            { 
                currentPos = Input.GetTouch(0).position;            } 
        }        else { 
            currentPos = Input.mousePosition;        } 

        //Calculation is click ? 
        if (pressed)        { 
            previousTouch = currentPos;        } 
        else {            if (Vector3.Distance(previousTouch, currentPos) < 20.0f) { isClick = true; } 
        } 

        if (enabled && NGUITools.GetActive(gameObject) && draggablePanel != null)        { 
            QRCUIDraggablePanel qrcDraggablePanel = draggablePanel as QRCUIDraggablePanel;             
            if (isClick)            { 
                qrcDraggablePanel.Press(false, gameObject);            } 
            else {                qrcDraggablePanel.Press(pressed, null); 
            }        } 

        isClick = false; 
    } 

    private bool IsClick() {        if (Application.platform == RuntimePlatform.IPhonePlayer || Application.platform == RuntimePlatform.Android) { 
            if (Input.touchCount > 0)            { 
                previousTouch = Input.GetTouch(0).position;            } 
        }        return true; 
    } 

    //protected void OnClick()    //{ 
    //    if (enabled && NGUITools.GetActive(gameObject) && draggablePanel != null)    //    { 
    //        QRCUIDraggablePanel qrcDraggablePanel = draggablePanel as QRCUIDraggablePanel;    //        qrcDraggablePanel.Press(false, gameObject); 
    //    }    //} 

}