聊聊GridView实现拖拽排序及数据交互的问题

在研究项目中的一个效果的时候，查找资料过程中发现有人有这么一种需求，就是GridView在实现拖拽排序的基础上，如果是两个GridView之间实现拖拽效果，并要实现数据交互。

一、效果图：

实现这个效果需要考虑的事情：

　　① 这个UI整体的构建以及事件的传递

　　② 如何实现View的共享，穿过边界

二、实现思路：

　　对于单个GridView的拖拽效果实现是参考网上的一篇文章，很抱歉没能及时保存地址，所以这里就不贴了。

　　整体实现： 一个容器（DragChessView）里放置两个DragView(可拖拽排序Item的View)，事件全部交给DragChessView去处理，然后由他去控制事件的分配和处理。在这个容器中还在这两个DragView上面覆盖一层FrameLayout，来放置要移动的那个View，然后根据手势去移动View。DragView里面进行View的动态交换以及数据交换。

三、实现代码：

1. DragChessView代码

public class DragChessView extends FrameLayout {
private GestureDetector detector;
/**
* 点击拖动
*/
public static final int DRAG_WHEN_TOUCH = 0;
/**
* 长按拖动
*/
public static final int DRAG_BY_LONG_CLICK = 1;
private int mDragMode = DRAG_WHEN_TOUCH;
private boolean hasSendDragMsg = false;
private Handler handler = new Handler(new Handler.Callback() {
@Override
public boolean handleMessage(Message msg) {
switch (msg.what) {
case 0x123:
// 启动拖拽模式
isDragable = true;
// 根据点击的位置生成该位置上的view镜像
if (isTouchInTop(msg.arg2)) {
mDragTop.setCurrentDragPosition(msg.arg1);
copyView(mDragTop);
} else {
mDragBottom.setCurrentDragPosition(msg.arg1);
copyView(mDragBottom);
}
hasSendDragMsg = false;
break;
default:
break;
}
return false;
}
});
private boolean isDragable = true;
private float[] lastLocation = null;
private View mCopyView;
private OnTouchListener l;
// 转交给GridView一些常用监听器
private AdapterView.OnItemLongClickListener itemLongClickListener;
private int mTouchArea = 0;
private View dragSlider;
private Point mMovePoint; // 记录移动走向，上到下，还是下到上
/**
* @param itemClickListener
* @描述:item 转交给gridview一些常用监听器
*/
public void setOnItemClickListener(AdapterView.OnItemClickListener itemClickListener) {
mDragBottom.setOnItemClickListener(itemClickListener);
}
/**
* 长按监听器自己触发,点击拖动模式不存在长按
*
* @param
*/
public void setOnItemLongClickListener(AdapterView.OnItemLongClickListener itemLongClickListener) {
this.itemLongClickListener = itemLongClickListener;
}
private boolean canAddViewWhenDragChange = true;
private int mStartPoint;
private int START_DRAG_TOP = 0;
private int START_DRAG_BOTTOM = 1;
/**
* 手势监听器,滚动和单击
*/
private GestureDetector.SimpleOnGestureListener simpleOnGestureListener = new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
if (hasSendDragMsg) {
hasSendDragMsg = false;
handler.removeMessages(0x123);
}
if (isDragable && mCopyView != null) {
if (lastLocation == null && e1 != null) {
lastLocation = new float[]{e1.getRawX(), e1.getRawY()};
}
if (lastLocation == null)
lastLocation = new float[]{0, 0};
distanceX = lastLocation[0] - e2.getRawX();
distanceY = lastLocation[1] - e2.getRawY();
lastLocation[0] = e2.getRawX();
lastLocation[1] = e2.getRawY();
mCopyView.setX(mCopyView.getX() - distanceX);
mCopyView.setY(mCopyView.getY() - distanceY);
int to = eventToPosition(e2);
mCopyView.invalidate();
if (isDragInTop()) {
if (isDragFromBottom()) {
if (isDragBack(isDragInTop())) { //针对已经进入bottom区域，但是又返回来的情况
mStartPoint = START_DRAG_BOTTOM; //切换，保证移动过程中只执行一次
canAddViewWhenDragChange = true;
}
if (canAddViewWhenDragChange) {// 保证移动过程中，数据只有一次的添加
mDragTop.addSwapView(mDragBottom.getSwapData());
mDragBottom.removeSwapView();
canAddViewWhenDragChange = false;
if (hideView != null)
hideView.setVisibility(VISIBLE);
}
if (mDragTop.isViewInitDone()) {
mDragTop.setCurrentDragPosition(mDragTop.getGridChildCount() - 1);
hideView = mDragTop.getGridChildAt(mDragTop.getCurrentDragPosition());
if (hideView != null)
hideView.setVisibility(INVISIBLE);
mMovePoint = getDragViewCenterPoint(mDragTop);
}
}
if (mDragTop.isViewInitDone())
dragChangePosition(mDragTop, to);
} else {
if (isDragFromTop()) {
if (isDragBack(isDragInTop())) {
mStartPoint = START_DRAG_TOP;
canAddViewWhenDragChange = true;
}
if (canAddViewWhenDragChange) {
mDragBottom.addSwapView(mDragTop.getSwapData());
mDragTop.removeSwapView();
canAddViewWhenDragChange = false;
if (hideView != null)
hideView.setVisibility(VISIBLE);
}
if (mDragBottom.isViewInitDone()) {
mDragBottom.setCurrentDragPosition(mDragBottom.getGridChildCount() - 1);
hideView = mDragBottom.getGridChildAt(mDragBottom.getCurrentDragPosition());
if (hideView != null)
hideView.setVisibility(INVISIBLE);
Log.e("mMovePoint", mMovePoint.x + "-----------" + mMovePoint.y);
mMovePoint = getDragViewCenterPoint(mDragBottom);
}
}
if (mDragBottom.isViewInitDone())
dragChangePosition(mDragBottom, to);
}
}
return true;
}
@Override
public void onShowPress(MotionEvent e) {
/** 响应长按拖拽 */
if (mDragMode == DRAG_BY_LONG_CLICK) {
// 启动拖拽模式
// isDragable = true;
// 通知父控件不拦截我的事件
getParent().requestDisallowInterceptTouchEvent(true);
// 根据点击的位置生成该位置上的view镜像
int position = eventToPosition(e);
if (isCanDragMove(isTouchInTop(e) ? mDragTop : mDragBottom, position)) {
// copyView(currentDragPosition = position);
Message msg = handler.obtainMessage(0x123, position, (int) e.getY());
// showpress本身大概需要170毫秒
handler.sendMessageDelayed(msg, dragLongPressTime - 170);
mMovePoint = new Point((int) e.getX(), (int) e.getY());
mStartPoint = isTouchInTop(e) ? START_DRAG_TOP : START_DRAG_BOTTOM;
hasSendDragMsg = true;
}
}
}
};
private boolean isDragBack(boolean dragInTop) {
return (dragInTop && mStartPoint == START_DRAG_TOP) || (!dragInTop && mStartPoint == START_DRAG_BOTTOM);
}
private boolean isDragFromTop() {
if (mMovePoint != null && mDragTop != null) {
if ((mMovePoint.x > mDragTop.getX() && mMovePoint.x < (mDragTop.getX() + mDragTop.getWidth())) 　　　　　　　　　　&& (mMovePoint.y > mDragTop.getY() && mMovePoint.y < (mDragTop.getY() + mDragTop.getHeight()))) {
return true;
}
}
return false;
}
private Point getDragViewCenterPoint(DragView dragView) {
Point result = new Point();
if (dragView != null) {
int height = dragView.getHeight();
int width = dragView.getWidth();
float x = dragView.getX();
float y = dragView.getY();
result.set((int) (x + width / 2), (int) (y + height / 2));
}
return result;
}
private boolean isDragFromBottom() {
if (mMovePoint != null && mDragBottom != null) {
if ((mMovePoint.x > mDragBottom.getX() && mMovePoint.x < (mDragBottom.getX() + mDragBottom.getWidth())) 　　　　　　　　　　　&& (mMovePoint.y > mDragBottom.getY() && mMovePoint.y < (mDragBottom.getY() + mDragBottom.getHeight()))) {
return true;
}
}
return false;
}
private boolean isTouchInTop(MotionEvent event) {
float y = event.getY();
return isTouchInTop(y);
}
private boolean isTouchInTop(float y) {
return y > mDragTop.getY() && y < (mDragTop.getY() + mDragTop.getHeight());
}
private void dragChangePosition(DragView dragView, int to) {
if (to != dragView.getCurrentDragPosition() && isCanDragMove(dragView, to)) {
dragView.onDragPositionChange(dragView.getCurrentDragPosition(), to);
}
}
private boolean isCanDragMove(DragView dragView, int position) {
return position >= dragView.getHeadDragPosition() && position < dragView.getGridChildCount() - dragView.getFootDragPosition();
}
private FrameLayout mDragFrame;
private DragView mDragBottom;
private DragView mDragTop;
private View hideView;
private long dragLongPressTime = 600;
public DragChessView(@NonNull Context context) {
this(context, null);
}
public DragChessView(@NonNull Context context, @Nullable AttributeSet attrs) {
this(context, attrs, -1);
}
public DragChessView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(attrs);
}
private void init(AttributeSet attrs) {
Context context = getContext();
detector = new GestureDetector(context, simpleOnGestureListener);
detector.setIsLongpressEnabled(false);
mDragFrame = new FrameLayout(context);
dragSlider = LayoutInflater.from(context).inflate(R.layout.layout_drag_chess, this, false);
mDragTop = dragSlider.findViewById(R.id.drag_top);
mDragBottom = dragSlider.findViewById(R.id.drag_bottom);
addView(dragSlider, -1, -1);
addView(mDragFrame, -1, -1);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (l != null) {
l.onTouch(this, ev);
}
if (!isViewInitDone()) {
return false;
}
if (isDragable) {
handleScrollAndCreMirror(ev);
} else {
// 交给子控件自己处理
dispatchEvent(isTouchInTop(ev) ? mDragTop : mDragBottom, ev);
}
// 处理拖动
detector.onTouchEvent(ev);
if (ev.getAction() == MotionEvent.ACTION_CANCEL || ev.getAction() == MotionEvent.ACTION_UP) {
lastLocation = null;
if (hasSendDragMsg) {
hasSendDragMsg = false;
handler.removeMessages(0x123);
}
}
return true;
}
private void dispatchEvent(DragView dragView, MotionEvent ev) {
dragView.dispatchEvent(ev);
}
private boolean isDragInTop() {
if (mCopyView == null)
return false;
return (mCopyView.getY() + mCopyView.getHeight()) < (mDragTop.getY() + mDragTop.getBottom());
}
/**
* Description :拦截所有事件
*/
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
return true;
}
/**
* 处理自动滚屏,和单击生成镜像
*/
private void handleScrollAndCreMirror(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
// 通知父控件不拦截我的事件
getParent().requestDisallowInterceptTouchEvent(true);
// 根据点击的位置生成该位置上的view镜像
int position = eventToPosition(ev);
makeCopyView(isTouchInTop(ev) ? mDragTop : mDragBottom, position);
break;
case MotionEvent.ACTION_MOVE:
getParent().requestDisallowInterceptTouchEvent(true);// 通知父控件不拦截我的事件
// 内容太多时,移动到边缘会自动滚动
decodeScrollArea(isDragInTop() ? mDragTop : mDragBottom, ev);
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
if (hideView != null) {
hideView.setVisibility(View.VISIBLE);
if (onDragSelectListener != null) {
onDragSelectListener.onPutDown(hideView);
}
}
mDragFrame.removeAllViews();
// mDragFrame.scrollTo(0, 0);
// isNotifyByDragSort = true;
updateUI(isDragInTop() ? mDragTop : mDragBottom, ev);
mCopyView = null;
canAddViewWhenDragChange = true;
// 放手时取消拖动排序模式
if (mDragMode == DRAG_BY_LONG_CLICK) {
isDragable = false;
}
break;
default:
break;
}
}
private void updateUI(DragView dragView, MotionEvent ev) {
if (dragView.isHasPositionChange()) {
dragView.setHasPositionChange(false);
dragView.getAdapter().notifyDataSetChanged();
} else if (mDragMode == DRAG_BY_LONG_CLICK && itemLongClickListener != null) {
dragView.onItemLongClick(itemLongClickListener);
}
// 停止滚动
if (dragView.isCanScroll()) {
int scrollStates2 = dragView.decodeTouchArea(ev);
if (scrollStates2 != 0) {
dragView.onTouchAreaChange(0);
mTouchArea = 0;
}
}
}
private void decodeScrollArea(DragView dragView, MotionEvent ev) {
if (dragView.isCanScroll()) {
int touchArea = dragView.decodeTouchArea(ev);
if (touchArea != mTouchArea) {
dragView.onTouchAreaChange(touchArea);
mTouchArea = touchArea;
}
}
}
private void makeCopyView(DragView dragView, int position) {
if (position >= dragView.getHeadDragPosition() && position < dragView.getGridChildCount() - dragView.getFootDragPosition()) {
dragView.setCurrentDragPosition(position);
copyView(dragView);
}
}
/**
* 得到事件触发点, 摸到的是哪一个item
*/
public int eventToPosition(MotionEvent ev) {
if (ev != null) {
if (isTouchInTop(ev))
return mDragTop.eventToPosition(ev);
return mDragBottom.eventToPosition(ev);
}
return 0;
}
/**
* 复制一个镜像,并添加到透明层
*/
private void copyView(DragView dragView) {
// TODO: 2018/4/2 创建可移动的 item
hideView = dragView.getGridChildAt(dragView.getCurrentDragPosition());
int realPosition = dragView.getGridChildPos(hideView);
DragAdapter adapter = dragView.getAdapter();
if (!adapter.isUseCopyView()) {
mCopyView = adapter.getView(realPosition, mCopyView, mDragFrame);
} else {
mCopyView = adapter.copyView(realPosition, mCopyView, mDragFrame);
}
hideView.setVisibility(View.INVISIBLE);
if (mCopyView.getParent() == null)
mDragFrame.addView(mCopyView, dragView.getmColWidth(), dragView.getmColHeight());
int[] l1 = new int[2];
int[] l2 = new int[2];
hideView.getLocationOnScreen(l1);
mDragFrame.getLocationOnScreen(l2);
// mCopyView.setX(hideView.getLeft());
// mCopyView.setY(hideView.getTop() - mCurrentY);
mCopyView.setX(l1[0] - l2[0]);
mCopyView.setY(l1[1] - l2[1]);
if (onDragSelectListener == null) {
mCopyView.setScaleX(1.2f);
mCopyView.setScaleY(1.2f);
} else {
onDragSelectListener.onDragSelect(mCopyView);
}
}
private DragSortGridView.OnDragSelectListener onDragSelectListener;
/**
* @描述:一个item view刚被拖拽和放下时起来生成镜像时调用.
*/
public void setOnDragSelectListener(DragSortGridView.OnDragSelectListener onDragSelectListener) {
this.onDragSelectListener = onDragSelectListener;
}
/**
* @param mode int类型
* @描述:设置拖动的策略是点击还是长按
*/
public void setDragModel(int mode) {
this.mDragMode = mode;
isDragable = mode == DRAG_WHEN_TOUCH;
}
public void setAnimFrame(ListenFrameLayout mDragFrame) {
this.mDragFrame = mDragFrame;
}
/**
* 设置长按需要用时
*
* @param time
*/
public void setDragLongPressTime(long time) {
dragLongPressTime = time;
}
public void setBottomAdapter(@NotNull DragAdapter adapter) {
mDragBottom.setAdapter(adapter);
}
public boolean isViewInitDone() {
boolean result = mDragBottom.isViewInitDone();
if (mDragTop.getVisibility() == VISIBLE)
result &= mDragTop.isViewInitDone();
return result;
}
public void setTopAdapter(@NotNull DragAdapter adapter) {
mDragTop.setAdapter(adapter);
}
}

2. DragView的实现：

public class DragView<T> extends FrameLayout {
private static final int TAG_KEY = R.id.first;
private NoScrollGridView mGridView;
private List<View> mChilds = new ArrayList<View>();
protected int mNumColumns = 3;
protected int mColHeight = 0;
protected int mColWidth = 0;
protected int mChildCount = 0;
protected int mMaxHeight = 0;
private boolean isViewInitDone = false;
private ListenScrollView mScrollView;
private int mCurrentY = 0;
/**
* 自动滚屏的动画
*/
private ValueAnimator animator;
private DragAdapter adapter;
private int headDragPosition = 0;
private int footDragPosition = 0;
private int currentDragPosition = -1;
/**
* 是否有位置发生改变,否则不用重绘
*/
private boolean hasPositionChange = false;
/**
* gridview能否滚动,是否内容太多
*/
private boolean canScroll = true;
/**
* 动画时间
*/
private static final long ANIM_DURING = 250;
private Object swapeData;
public DragView(@NonNull Context context) {
this(context, null);
}
public DragView(@NonNull Context context, @Nullable AttributeSet attrs) {
this(context, attrs, -1);
}
public DragView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
Context context = getContext();
mGridView = new NoScrollGridView(context);
mGridView.setVerticalScrollBarEnabled(false);
mGridView.setStretchMode(GridView.STRETCH_COLUMN_WIDTH);
mGridView.setSelector(new ColorDrawable());
// View的宽高之类必须在测量,布局,绘制一系列过程之后才能获取到
mGridView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
if (mChilds.isEmpty()) {
for (int i = 0; i < mGridView.getChildCount(); i++) {
View view = mGridView.getChildAt(i);
view.setTag(TAG_KEY, new int[]{0, 0});
view.clearAnimation();
mChilds.add(view);
}
}
if (!mChilds.isEmpty()) {
mColHeight = mChilds.get(0).getHeight();
}
mColWidth = mGridView.getColumnWidth();
if (mChildCount % mNumColumns == 0) {
mMaxHeight = mColHeight * mChildCount / mNumColumns;
} else {
mMaxHeight = mColHeight * (mChildCount / mNumColumns + 1);
}
canScroll = mMaxHeight - getHeight() > 0;
// 告知事件处理,完成View加载,许多属性也已经初始化了
isViewInitDone = true;
}
});
mScrollView = new ListenScrollView(context);
mGridView.setNumColumns(mNumColumns);
mScrollView.addView(mGridView, -1, -1);
addView(mScrollView, -1, -1);
}
private DataSetObserver observer = new DataSetObserver() {
@Override
public void onChanged() {
mChildCount = adapter.getCount();
// 下列属性状态清除,才会在被调用notifyDataSetChange时,在gridview测量布局完成后重新获取
mChilds.clear();
mColHeight = mColWidth = mMaxHeight = 0;
isViewInitDone = false;
}
@Override
public void onInvalidated() {
mChildCount = adapter.getCount();
}
};
/**
* 控制自动滚屏的动画监听器.
*/
private ValueAnimator.AnimatorUpdateListener animUpdateListener = new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
int targetY = Math.round((Float) animation.getAnimatedValue());
if (targetY < 0) {
targetY = 0;
} else if (targetY > mMaxHeight - getHeight()) {
targetY = mMaxHeight - getHeight();
}
// mGridView.scrollTo(0, targetY);
mScrollView.smoothScrollTo(0, targetY);
// mCurrentY = targetY;
}
};
public void setAdapter(DragAdapter adapter) {
if (this.adapter != null && observer != null) {
this.adapter.unregisterDataSetObserver(observer);
}
this.adapter = adapter;
mGridView.setAdapter(adapter);
adapter.registerDataSetObserver(observer);
mChildCount = adapter.getCount();
}
/**
* @param from
* @param to
* @描述:动画效果移动View
*/
public void translateView(int from, int to) {
View view = mChilds.get(from);
int fromXValue = ((int[]) view.getTag(TAG_KEY))[0];
int fromYValue = ((int[]) view.getTag(TAG_KEY))[1];
int toXValue = to % mNumColumns - from % mNumColumns + fromXValue;
int toYValue = to / mNumColumns - from / mNumColumns + fromYValue;
Animation animation = new TranslateAnimation(1, fromXValue, 1, toXValue, 1, fromYValue, 1, toYValue);
animation.setDuration(ANIM_DURING);
animation.setFillAfter(true);
view.setTag(TAG_KEY, new int[]{toXValue, toYValue});
view.startAnimation(animation);
}
/**
* @param from
* @param to
* @描述:拖动View使位置发生改变时
*/
public void onDragPositionChange(int from, int to) {
if (from > to) {
for (int i = to; i < from; i++) {
translateView(i, i + 1);
}
} else {
for (int i = to; i > from; i--) {
translateView(i, i - 1);
}
}
if (!hasPositionChange) {
hasPositionChange = true;
}
if ((from >= mChilds.size() || from < 0) || (to >= mChilds.size() || to < 0))
return;
adapter.onDataModelMove(from, to);
View view = mChilds.remove(from);
mChilds.add(to, view);
currentDragPosition = to;
}
/**
* @param scrollStates
* @描述:触摸区域改变,做相应处理,开始滚动或停止滚动
*/
public void onTouchAreaChange(int scrollStates) {
if (!canScroll) {
return;
}
if (animator != null) {
animator.removeUpdateListener(animUpdateListener);
}
if (scrollStates == 1) {// 从普通区域进入触发向上滚动的区域
int instance = mMaxHeight - getHeight() - mCurrentY;
animator = ValueAnimator.ofFloat(mCurrentY, mMaxHeight - getHeight());
animator.setDuration((long) (instance / 0.5f));
animator.setTarget(mGridView);
animator.addUpdateListener(animUpdateListener);
animator.start();
} else if (scrollStates == -1) {// 进入触发向下滚动的区域
animator = ValueAnimator.ofFloat(mCurrentY, 0);
animator.setDuration((long) (mCurrentY / 0.5f));
animator.setTarget(mGridView);
animator.addUpdateListener(animUpdateListener);
animator.start();
}
}
/**
* @param ev 事件
* @return 0中间区域, 1底部,-1顶部
* @描述: 检查当前触摸事件位于哪个区域, 顶部1/5可能触发下滚,底部1/5可能触发上滚
*/
public int decodeTouchArea(MotionEvent ev) {
if (ev.getY() > (getHeight() + getY()) * 4 / (double) 5) {
return 1;
} else if (ev.getY() < (getHeight() + getY()) / (double) 5) {
return -1;
} else {
return 0;
}
}
public boolean isViewInitDone() {
return isViewInitDone;
}
/**
* 设置前几个item不可以改变位置
*/
public void setNoPositionChangeItemCount(int count) {
headDragPosition = count;
}
/**
* 设置后几个item不可以改变位置
*/
public void setFootNoPositionChangeItemCount(int count) {
footDragPosition = count;
}
public int getHeadDragPosition() {
return headDragPosition;
}
public int getFootDragPosition() {
return footDragPosition;
}
public int getGridChildCount() {
return mChilds.size();
}
public View getGridChildAt(int position) {
if (position < 0 || position >= mChilds.size())
return null;
return mChilds.get(position);
}
public int getGridChildPos(View view) {
return mGridView.indexOfChild(view);
}
public void setCurrentDragPosition(int currentDragPosition) {
this.currentDragPosition = currentDragPosition;
}
public int getCurrentDragPosition() {
return currentDragPosition;
}
public int getmColHeight() {
return mColHeight;
}
public int getmColWidth() {
return mColWidth;
}
public DragAdapter getAdapter() {
return adapter;
}
public boolean isHasPositionChange() {
return hasPositionChange;
}
public void setHasPositionChange(boolean hasPositionChange) {
this.hasPositionChange = hasPositionChange;
}
public boolean isCanScroll() {
return canScroll;
}
public void setOnItemClickListener(AdapterView.OnItemClickListener onItemClickListener) {
mGridView.setOnItemClickListener(onItemClickListener);
}
public void onItemLongClick(AdapterView.OnItemLongClickListener itemLongClickListener) {
itemLongClickListener.onItemLongClick(mGridView, childAt(currentDragPosition), currentDragPosition, 0);
}
public View childAt(int index) {
return mGridView.getChildAt(index);
}
public void dispatchEvent(MotionEvent ev) {
if (canScroll)
mScrollView.dispatchTouchEvent(ev);
else
mGridView.dispatchTouchEvent(ev);
}
public int eventToPosition(MotionEvent ev) {
if (ev != null) {
int m = (int) ev.getX() / mColWidth;
int n = (int) (ev.getY() - getY() + mCurrentY) / mColHeight;
int position = n * mNumColumns + m;
if (position >= mChildCount) {
return mChildCount - 1;
} else {
return position;
}
}
return 0;
}
public void addSwapView(Object data) {
adapter.addNewData(data);
}
public Object getSwapData() {
return adapter.getSwapData(currentDragPosition);
}
public void removeSwapView() {
if (adapter != null) {
adapter.removeData(currentDragPosition);
adapter.notifyDataSetChanged();
}
}
class ListenScrollView extends ScrollView {
public ListenScrollView(Context context) {
super(context);
}
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
mCurrentY = getScrollY();
}
}
class NoScrollGridView extends GridView {
public NoScrollGridView(Context context) {
super(context);
}
/**
* @return
* @描述:兼容老版本的getColumWidth
* @作者 [pWX273343] 2015年7月1日
*/
public int getColumnWidth() {
return getWidth() / getNumColumns();
}
public NoScrollGridView(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int mExpandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, mExpandSpec);
}
}
}

3. DragAdapter的代码：

public abstract class DragAdapter extends BaseAdapter {
/**
* @param from
* @param to
* @描述:当从from排序被拖到to排序时的处理方式,请对相应的数据做处理。
*/
public abstract void onDataModelMove(int from, int to);
/**
* 复制View使用的方法,默认直接使用getView方法获取
*
* @param position
* @param convertView
* @param parent
* @return
*/
public View copyView(int position, View convertView, ViewGroup parent) {
return null;
}
/**
* 是否启用copyView方法
*
* @return true 使用copyView复制 false 使用getView直接获取镜像
*/
public boolean isUseCopyView() {
return false;
}
public abstract Object getSwapData(int position);
public abstract void removeData(int position);
public void addNewData(Object data) {
}
}

4.使用MainActivity:

class GridDragShortActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
window.attributes.systemUiVisibility = View.SYSTEM_UI_FLAG_FULLSCREEN or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　or View.SYSTEM_UI_FLAG_IMMERSIVE or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
setContentView(R.layout.activity_grid_drag_short)
//长按item响应该item的拖动排序,默认是触摸就开始拖动
drag_main.setDragModel(DragSortGridView.DRAG_BY_LONG_CLICK)
//设置每行个数
//        drag_main.numColumns = 3
var arrayList = ArrayList<String>()
var list = ArrayList<String>()
for (i in 0..29) {
arrayList.add("" + i)
}
for (i in 0..29) {
list.add(('A' + i).toString())
}
drag_main.setBottomAdapter(CustomAdapter(list, this))
drag_main.setTopAdapter(CustomAdapter(arrayList, this))
}
}

布局：activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.mdzz.DragChessView
android:id="@+id/drag_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
</RelativeLayout>

布局 layout_drag_chess.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.chineseall.bookshelf.mdzz.DragView
android:id="@+id/drag_top"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#ffffff" />
<TextView
android:id="@+id/folder_title"
android:layout_width="match_parent"
android:layout_height="40dp"
android:background="#0586F9"
android:gravity="center"
android:text="@string/text"
android:textColor="#ffffff"
android:textSize="18sp" />
<com.chineseall.bookshelf.mdzz.DragView
android:id="@+id/drag_bottom"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#ffffff" />
</LinearLayout>

在实际使用中，可以更据需要再去拓展使用，代码演变过程中的另一个效果，来看看，以它结束这篇：

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