仿微信朋友圈图片拖拽更换位置,拖拽删除hzqit520的博客-

这是使用ItemTouchHelper技术实现一个选择相册后,仿微信朋友圈图片拖拽更换位置,拖拽删除的一个功能.希望可以帮到大家.

完整项目地址:https://download.csdn.net/download/hzqit520/12342742

项目演示如下图:

主要的代码如下:

 mItemTouchHelper = new ItemTouchHelper(new ItemTouchHelper.Callback() {             @Override             public boolean isLongPressDragEnabled () {                 return true;             }              @Override             public void onSwiped (@NonNull RecyclerView.ViewHolder viewHolder, int direction) {             }              @Override             public int getMovementFlags (@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder) {                 int itemViewType = viewHolder.getItemViewType();                 if (itemViewType != GridImageAdapter.TYPE_CAMERA) {                     viewHolder.itemView.setAlpha(0.7f);                 }                 return makeMovementFlags(ItemTouchHelper.DOWN | ItemTouchHelper.UP                                                  | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT, 0);             }              @Override             public boolean onMove (@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder target) {                 //得到item原来的position                 try {                     int fromPosition = viewHolder.getAdapterPosition();                     //得到目标position                     int toPosition = target.getAdapterPosition();                     int itemViewType = target.getItemViewType();                     if (itemViewType != GridImageAdapter.TYPE_CAMERA) {                         if (fromPosition < toPosition) {                             for (int i = fromPosition; i < toPosition; i++) {                                 Collections.swap(mAdapter.getData(), i, i + 1);                             }                         } else {                             for (int i = fromPosition; i > toPosition; i--) {                                 Collections.swap(mAdapter.getData(), i, i - 1);                             }                         }                         mAdapter.notifyItemMoved(fromPosition, toPosition);                     }                 } catch (Exception e) {                     e.printStackTrace();                 }                 return true;             }              @Override             public void onChildDraw (@NonNull Canvas c, @NonNull RecyclerView recyclerView,                                      @NonNull RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {                 int itemViewType = viewHolder.getItemViewType();                 if (itemViewType != GridImageAdapter.TYPE_CAMERA) {                     if (null == mDragListener) {                         return;                     }                     if (needScaleBig) {                         //如果需要执行放大动画                         viewHolder.itemView.animate().scaleXBy(0.1f).scaleYBy(0.1f).setDuration(100);                         //执行完成放大动画,标记改掉                         needScaleBig = false;                         //默认不需要执行缩小动画，当执行完成放大 并且松手后才允许执行                         needScaleSmall = false;                     }                     int sh = recyclerView.getHeight() + mTvDeleteText.getHeight();                     int ry = mTvDeleteText.getTop() - sh;                     if (dY >= ry) {                         //拖到删除处                         mDragListener.deleteState(true);                         if (isUpward) {                             //在删除处放手，则删除item                             viewHolder.itemView.setVisibility(View.INVISIBLE);                             mAdapter.delete(viewHolder.getAdapterPosition());                             resetState();                             return;                         }                     } else {//没有到删除处                         if (View.INVISIBLE == viewHolder.itemView.getVisibility()) {                             //如果viewHolder不可见，则表示用户放手，重置删除区域状态                             mDragListener.dragState(false);                         }                         if (needScaleSmall) {//需要松手后才能执行                             viewHolder.itemView.animate().scaleXBy(1f).scaleYBy(1f).setDuration(100);                         }                         mDragListener.deleteState(false);                     }                     super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);                 }             }              @Override             public void onSelectedChanged (@Nullable RecyclerView.ViewHolder viewHolder, int actionState) {                 int itemViewType = viewHolder != null ? viewHolder.getItemViewType() : GridImageAdapter.TYPE_CAMERA;                 if (itemViewType != GridImageAdapter.TYPE_CAMERA) {                     if (ItemTouchHelper.ACTION_STATE_DRAG == actionState && mDragListener != null) {                         mDragListener.dragState(true);                     }                     super.onSelectedChanged(viewHolder, actionState);                 }             }              @Override             public long getAnimationDuration (@NonNull RecyclerView recyclerView, int animationType, float animateDx, float animateDy) {                 needScaleSmall = true;                 isUpward = true;                 return super.getAnimationDuration(recyclerView, animationType, animateDx, animateDy);             }              @Override             public void clearView (@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder) {                 int itemViewType = viewHolder.getItemViewType();                 if (itemViewType != GridImageAdapter.TYPE_CAMERA) {                     viewHolder.itemView.setAlpha(1.0f);                     super.clearView(recyclerView, viewHolder);                     mAdapter.notifyDataSetChanged();                     resetState();                 }             }         });           // 绑定拖拽事件         mItemTouchHelper.attachToRecyclerView(mRecyclerView);

底部删除的文字和图片改变是根据拖拽监听,通过接口控制的,代码如下:

 mDragListener = new DragListener() {             @Override             public void deleteState (boolean isDelete) {                 if (isDelete) {                     mTvDeleteText.setText("松手即可删除");                     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {                         mTvDeleteText.setCompoundDrawablesRelativeWithIntrinsicBounds(0, R.mipmap.icon_let_go_delete, 0, 0);                     }                 } else {                     mTvDeleteText.setText("拖动到此处删除");                     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {                         mTvDeleteText.setCompoundDrawablesRelativeWithIntrinsicBounds(0, R.mipmap.picture_icon_delete, 0, 0);                     }                 }             }              @Override             public void dragState (boolean isStart) {                 int visibility = mTvDeleteText.getVisibility();                 if (isStart) {                     if (visibility == View.GONE) {                         mTvDeleteText.animate().alpha(1).setDuration(300).setInterpolator(new AccelerateInterpolator());                         mTvDeleteText.setVisibility(View.VISIBLE);                     }                 } else {                     if (visibility == View.VISIBLE) {                         mTvDeleteText.animate().alpha(0).setDuration(300).setInterpolator(new AccelerateInterpolator());                         mTvDeleteText.setVisibility(View.GONE);                     }                 }             }         };