我正在尝试在android C＃中实现拖动并重新安排listview项目。但是我得到一个类未找到错误。有人可以看看它，让我知道我做错了什么？
我的主要XML文件：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/mainLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ListViewAnimations">
<com.example.dragTest.DraggableListView
android:id="@+id/listview"
android:background="#0000"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</RelativeLayout>
我的主要活动类：
protected override void OnCreate (Bundle bundle)
{
base.OnCreate (bundle);
// Set our view from the "main" layout resource
// Set our view from the "main" layout resource
SetContentView (Resource.Layout.Main);
var list = FindViewById<DraggableListView>(Resource.Id.listview);
items = new List<string> {
"Vegetables",
"Fruits",
"Flower Buds",
"Legumes",
"Vegetables",
"Fruits",
"Flower Buds",
"Legumes",
};
list.Adapter = new DraggableListAdapter (this, items);
}
我的自定义DraggableListView类：
public class DraggableListView : ListView, ITypeEvaluator, GestureDetector.IOnGestureListener
{
bool _reorderingEnabled = true;
public bool ReorderingEnabled {
get {
return _reorderingEnabled;
}
set {
if (!value) {
ItemLongClick -= HandleItemLongClick;
} else {
ItemLongClick += HandleItemLongClick;
}
_reorderingEnabled = value;
}
}
const int LINE_THICKNESS = 15;
const int INVALID_ID = -1;
const int INVALID_POINTER_ID = -1;
int mLastEventY = -1;
int mDownY = -1;
int mDownX = -1;
int mTotalOffset = 0;
int mActivePointerId = INVALID_POINTER_ID;
bool mCellIsMobile = false;
long mAboveItemId = INVALID_ID;
long mMobileItemId = INVALID_ID;
long mBelowItemId = INVALID_ID;
View mobileView;
Rect mHoverCellCurrentBounds;
Rect mHoverCellOriginalBounds;
BitmapDrawable mHoverCell;
GestureDetector dectector;
///
/// Constructors
///
public DraggableListView (Context context) : base (context)
{
init (context);
}
public DraggableListView (Context context, IAttributeSet attrs, int defStyle) : base (context, attrs, defStyle)
{
init (context);
}
public DraggableListView (Context context, IAttributeSet attrs) : base (context, attrs)
{
init (context);
}
public void init (Context context)
{
// the detector handles all the gestures
dectector = new GestureDetector (this);
ItemLongClick += HandleItemLongClick;
}
#region Handlers
void HandleItemLongClick (object sender, ItemLongClickEventArgs e)
{
// Long press is handeled in the OnLongPress method of the IOnGestureListener Interface
// for some reason we have to wire this up to detect the long press, otherwise, the gesture gets ignored
}
void HandleHoverAnimatorUpdate (object sender, ValueAnimator.AnimatorUpdateEventArgs e)
{
Invalidate ();
}
void HandleHoverAnimationStart (object sender, EventArgs e)
{
Enabled = false;
}
/// <summary>
/// Resets the global variables and visbility of the mobile view
/// </summary>
void HandleHoverAnimationEnd (object sender, EventArgs e)
{
mAboveItemId = INVALID_ID;
mMobileItemId = INVALID_ID;
mBelowItemId = INVALID_ID;
mHoverCell = null;
Enabled = true;
Invalidate ();
mobileView.Visibility = ViewStates.Visible;
}
#endregion
#region IOnGestureListener Implementation
public bool OnDown (MotionEvent e)
{
return true;
}
/// <summary>
/// Determines if the touch event was right or left swipe
/// </summary>
public bool OnFling (MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
{
return false;
}
public bool OnSingleTapUp (MotionEvent e)
{
return false;
}
/// <summary>
/// Handles the item long click by hiding the selected view, creating the dummy view drawable and adding it to the screen
/// </summary>
public void OnLongPress (MotionEvent e)
{
mTotalOffset = 0;
int position = PointToPosition (mDownX, mDownY);
if (position < 0 || !LongClickable)
return;
int itemNum = position - FirstVisiblePosition;
View selectedView = GetChildAt (itemNum);
mMobileItemId = Adapter.GetItemId (position); // use this varable to keep track of which view is currently moving
mHoverCell = GetAndAddHoverView (selectedView);
selectedView.Visibility = ViewStates.Invisible; // set the visibility of the selected view to invisible
mCellIsMobile = true;
UpdateNeighborViewsForID (mMobileItemId);
}
public bool OnScroll (MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
{
return false;
}
public void OnShowPress (MotionEvent e)
{
}
#endregion
#region Bitmap Drawable Creation
/// <summary>
/// Creates the hover cell with the appropriate bitmap and of appropriate
/// size. The hover cell's BitmapDrawable is drawn on top of the bitmap every
/// single time an invalidate call is made.
/// </summary>
BitmapDrawable GetAndAddHoverView (View v)
{
int w = v.Width;
int h = v.Height;
int top = v.Top;
int left = v.Left;
Bitmap b = GetBitmapWithBorder (v);
BitmapDrawable drawable = new BitmapDrawable (Resources, b);
mHoverCellOriginalBounds = new Rect (left, top, left + w, top + h);
mHoverCellCurrentBounds = new Rect (mHoverCellOriginalBounds);
drawable.SetBounds (left, top, left + w, top + h);
return drawable;
}
/// <summary>
/// Draws a red border over the screenshot of the view passed in.
/// </summary>
static Bitmap GetBitmapWithBorder (View v)
{
Bitmap bitmap = GetBitmapFromView (v);
Canvas can = new Canvas (bitmap);
Rect rect = new Rect (0, 0, bitmap.Width, bitmap.Height);
Paint paint = new Paint ();
paint.SetStyle (Paint.Style.Stroke);
paint.StrokeWidth = LINE_THICKNESS;
paint.Color = Color.Red;
can.DrawBitmap (bitmap, 0, 0, null);
can.DrawRect (rect, paint);
return bitmap;
}
/// <summary>
/// Returns a bitmap showing a screenshot of the view passed in
/// </summary>
static Bitmap GetBitmapFromView (View v)
{
try {
Bitmap bitmap = Bitmap.CreateBitmap (v.Width, v.Height, Bitmap.Config.Argb8888);
Canvas canvas = new Canvas (bitmap);
v.Draw (canvas);
return bitmap;
} catch (Exception ex) {
Console.WriteLine (ex.Message);
}
return default(Bitmap);
}
#endregion
/// <summary>
/// Stores a reference to the views above and below the item currently
/// corresponding to the hover cell. It is important to note that if this
/// item is either at the top or bottom of the list, mAboveItemId or mBelowItemId
/// may be invalid.
void UpdateNeighborViewsForID (long itemID)
{
int position = GetPositionForID (itemID);
mAboveItemId = Adapter.GetItemId (position - 1);
mBelowItemId = Adapter.GetItemId (position + 1);
}
/// <summary>
/// Retrieves the view in the list corresponding to itemID
/// </summary>
public View GetViewForID (long itemID)
{
for (int i = 0; i < ChildCount; i++) {
View v = GetChildAt (i);
int position = FirstVisiblePosition + i;
long id = Adapter.GetItemId (position);
if (id == itemID) {
return v;
}
}
return null;
}
/// <summary>
/// Retrieves the position in the list corresponding to itemID
/// </summary>
public int GetPositionForID (long itemID)
{
View v = GetViewForID (itemID);
if (v == null) {
return -1;
} else {
return GetPositionForView (v);
}
}
/// <summary>
/// DispatchDraw gets invoked when all the child views are about to be drawn.
/// By overriding this method, the hover cell (BitmapDrawable) can be drawn
/// over the listview's items whenever the listview is redrawn.
/// </summary>
protected override void DispatchDraw (Canvas canvas)
{
base.DispatchDraw (canvas);
if (mHoverCell != null) {
mHoverCell.Draw (canvas);
}
}
/// <summary>
/// Gets data related to touch events, moves the bitmap drawable to location of touch, and calls the HandleCellSwitch method to animate cell swaps
/// </summary>
public override bool OnTouchEvent (MotionEvent e)
{
try {
dectector.OnTouchEvent (e);
switch (e.Action) {
case MotionEventActions.Down:
mDownX = (int)e.GetX ();
mDownY = (int)e.GetY ();
mActivePointerId = e.GetPointerId (0);
break;
case MotionEventActions.Move:
if (mActivePointerId == INVALID_POINTER_ID)
break;
int pointerIndex = e.FindPointerIndex (mActivePointerId);
mLastEventY = (int)e.GetY (pointerIndex);
int deltaY = mLastEventY - mDownY;
if (mCellIsMobile) { // Responsible for moving the bitmap drawable to the touch location
Enabled = false;
mHoverCellCurrentBounds.OffsetTo (mHoverCellOriginalBounds.Left,
mHoverCellOriginalBounds.Top + deltaY + mTotalOffset);
mHoverCell.SetBounds (mHoverCellCurrentBounds.Left, mHoverCellCurrentBounds.Top, mHoverCellCurrentBounds.Right, mHoverCellCurrentBounds.Bottom);
Invalidate ();
HandleCellSwitch ();
}
break;
case MotionEventActions.Up:
TouchEventsEnded ();
break;
case MotionEventActions.Cancel:
TouchEventsCancelled ();
break;
default:
break;
}
} catch (Exception ex) {
Console.WriteLine ("Error Processing OnTouchEvent in DynamicListView.cs - Message: {0}", ex.Message);
Console.WriteLine ("Error Processing OnTouchEvent in DynamicListView.cs - Stacktrace: {0}", ex.StackTrace);
}
return base.OnTouchEvent (e);
}
/// <summary>
/// This Method handles the animation of the cells switching as also switches the underlying data set
/// </summary>
void HandleCellSwitch ()
{
try {
int deltaY = mLastEventY - mDownY; // total distance moved since the last movement
int deltaYTotal = mHoverCellOriginalBounds.Top + mTotalOffset + deltaY; // total distance moved from original long press position
View belowView = GetViewForID (mBelowItemId); // the view currently below the mobile item
View mobileView = GetViewForID (mMobileItemId); // the current mobile item view (this is NOT what you see moving around, thats just a dummy, this is the "invisible" cell on the list)
View aboveView = GetViewForID (mAboveItemId); // the view currently above the mobile item
// Detect if we have moved the drawable enough to justify a cell swap
bool isBelow = (belowView != null) && (deltaYTotal > belowView.Top);
bool isAbove = (aboveView != null) && (deltaYTotal < aboveView.Top);
if (isBelow || isAbove) {
View switchView = isBelow ? belowView : aboveView; // get the view we need to animate
var diff = GetViewForID (mMobileItemId).Top - switchView.Top; // the difference between the top of the mobile view and top of the view we are about to switch with
// Lets animate the view sliding into its new position. Remember: the listview cell corresponding the mobile item is invisible so it looks like
// the switch view is just sliding into position
ObjectAnimator anim = ObjectAnimator.OfFloat (switchView, "TranslationY", switchView.TranslationY, switchView.TranslationY + diff);
anim.SetDuration (100);
anim.Start ();
// Swap out the mobile item id
mMobileItemId = GetPositionForView (switchView);
// Since the mobile item id has been updated, we also need to make sure and update the above and below item ids
UpdateNeighborViewsForID (mMobileItemId);
// One the animation ends, we want to adjust out visiblity
anim.AnimationEnd += (sender, e) => {
// Swap the visbility of the views corresponding to the data items being swapped - since the "switchView" will become the "mobileView"
// mobileView.Visibility = ViewStates.Visible;
// switchView.Visibility = ViewStates.Invisible;
// Swap the items in the data source and then NotifyDataSetChanged()
((IDraggableListAdapter)Adapter).SwapItems (GetPositionForView (mobileView), GetPositionForView (switchView));
};
}
} catch (Exception ex) {
Console.WriteLine ("Error Switching Cells in DynamicListView.cs - Message: {0}", ex.Message);
Console.WriteLine ("Error Switching Cells in DynamicListView.cs - Stacktrace: {0}", ex.StackTrace);
}
}
/// <summary>
/// Resets all the appropriate fields to a default state while also animating
/// the hover cell back to its correct location.
/// </summary>
void TouchEventsEnded ()
{
mobileView = GetViewForID (mMobileItemId);
if (mCellIsMobile) {
mCellIsMobile = false;
mActivePointerId = INVALID_POINTER_ID;
((DraggableListAdapter)Adapter).mMobileCellPosition = int.MinValue;
mHoverCellCurrentBounds.OffsetTo (mHoverCellOriginalBounds.Left, mobileView.Top);
ObjectAnimator hoverViewAnimator = ObjectAnimator.OfObject (mHoverCell, "Bounds", this, mHoverCellCurrentBounds);
hoverViewAnimator.Update += HandleHoverAnimatorUpdate;
hoverViewAnimator.AnimationStart += HandleHoverAnimationStart;
hoverViewAnimator.AnimationEnd += HandleHoverAnimationEnd;
hoverViewAnimator.Start ();
} else {
TouchEventsCancelled ();
}
}
/// <summary>
/// By Implementing the ITypeEvaluator Inferface, we are able to set this as the the ITypeEvaluator for the hoverViewAnimator
/// This method is responsible for animating the drawable to its final location after touch events end.
/// </summary>
public Java.Lang.Object Evaluate (float fraction, Java.Lang.Object startValue, Java.Lang.Object endValue)
{
var startValueRect = startValue as Rect;
var endValueRect = endValue as Rect;
return new Rect (Interpolate (startValueRect.Left, endValueRect.Left, fraction),
Interpolate (startValueRect.Top, endValueRect.Top, fraction),
Interpolate (startValueRect.Right, endValueRect.Right, fraction),
Interpolate (startValueRect.Bottom, endValueRect.Bottom, fraction));
}
/// <summary>
/// Interpolate the specified start, end and fraction for use in the Evaluate method above for a smooth animation
/// </summary>
public int Interpolate (int start, int end, float fraction)
{
return (int)(start + fraction * (end - start));
}
/// <summary>
/// Resets all the appropriate fields to a default state.
/// Resets the visibility of the currently mobile view
/// </summary>
void TouchEventsCancelled ()
{
mobileView = GetViewForID (mMobileItemId);
if (mCellIsMobile) {
mAboveItemId = INVALID_ID;
mMobileItemId = INVALID_ID;
mBelowItemId = INVALID_ID;
mHoverCell = null;
Invalidate ();
}
if (mobileView != null)
mobileView.Visibility = ViewStates.Visible;
Enabled = true;
mCellIsMobile = false;
mActivePointerId = INVALID_POINTER_ID;
}
}
答案 0 :(得分：0)
我在我的包名上犯了一个错误，这应该是我的命名空间，这解决了我的问题。