[WIP] DragSelectionItemTouchListener

library-extensions/src/main/java/com/mikepenz/fastadapter_extensions/drag/DragSelectionItemTouchListener.java

@@ -0,0 +1,117 @@
+package com.mikepenz.fastadapter_extensions.drag;
+
+import android.content.Context;
+import android.graphics.Rect;
+import android.support.v7.widget.GridLayoutManager;
+import android.support.v7.widget.RecyclerView;
+import android.view.MotionEvent;
+import android.view.View;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class DragSelectionItemTouchListener extends LongPressItemTouchListener implements RecyclerView.OnItemTouchListener {
+    private RecyclerView.ViewHolder mPreviousViewHolder;
+    private Rect mHitRect = new Rect();
+    private List<RecyclerView.ViewHolder> mRangeSelection = new ArrayList<>();
+
+
+    public DragSelectionItemTouchListener(Context context, OnItemInteractionListener listener) {
+        super(context, listener);
+    }
+
+    @Override
+    public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
+        if (e.getAction() == MotionEvent.ACTION_UP || e.getAction() == MotionEvent.ACTION_POINTER_UP) {
+            cancelPreviousSelection();
+            return false;
+        } else {
+            onLongPressedEvent(rv, e);
+        }
+        return mViewHolderLongPressed != null;
+    }
+
+    private void cancelPreviousSelection() {
+        mViewHolderLongPressed = null;
+        mViewHolderInFocus = null;
+        mPreviousViewHolder = null;
+        mRangeSelection.clear();
+    }
+
+    private boolean onActionMove(RecyclerView rv, MotionEvent e) {
+        if (isMotionEventInCurrentViewHolder(e) || mViewHolderLongPressed == null) {
+            return false;
+        }
+        if (mViewHolderLongPressed != null && mPreviousViewHolder == null) {
+            mPreviousViewHolder = mViewHolderLongPressed;
+        }
+        View childViewUnder = rv.findChildViewUnder(e.getX(), e.getY());
+        if (childViewUnder == null) return false;
+        RecyclerView.ViewHolder viewHolder = rv.getChildViewHolder(childViewUnder);
+        if (mPreviousViewHolder == null && viewHolder != null && mViewHolderLongPressed != null && viewHolder.getAdapterPosition() != mViewHolderLongPressed.getAdapterPosition()) {
+            dispatchOnViewHolderHovered(rv, viewHolder);
+            return true;
+        } else if (mPreviousViewHolder != null && viewHolder != null && viewHolder.getAdapterPosition() != mPreviousViewHolder.getAdapterPosition()) {
+            dispatchOnViewHolderHovered(rv, viewHolder);
+            return true;
+        }
+        return false;
+    }
+
+
+    private boolean isMotionEventInCurrentViewHolder(MotionEvent e) {
+        if (mPreviousViewHolder != null) {
+            mPreviousViewHolder.itemView.getHitRect(mHitRect);
+            return mHitRect.contains((int) e.getX(), (int) e.getY());
+        }
+        return false;
+    }
+
+    private void dispatchOnViewHolderHovered(RecyclerView rv, RecyclerView.ViewHolder viewHolder) {
+        if (!checkForSpanSelection(rv, viewHolder)) {
+            if (mListener != null) {
+                mListener.onViewHolderHovered(rv, viewHolder);
+            }
+        }
+        mPreviousViewHolder = viewHolder;
+    }
+
+    private boolean checkForSpanSelection(RecyclerView rv, RecyclerView.ViewHolder viewHolder) {
+        if (rv.getLayoutManager() instanceof GridLayoutManager) {
+            GridLayoutManager.LayoutParams endSelectionParams = (GridLayoutManager.LayoutParams) viewHolder.itemView.getLayoutParams();
+            GridLayoutManager.LayoutParams startSelectionParams = (GridLayoutManager.LayoutParams) mPreviousViewHolder.itemView.getLayoutParams();
+            if (endSelectionParams.getSpanIndex() != startSelectionParams.getSpanIndex()) {
+                dispatchRangeSelection(rv, viewHolder);
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private void dispatchRangeSelection(RecyclerView rv, RecyclerView.ViewHolder viewHolder) {
+        if (mListener != null) {
+            mRangeSelection.clear();
+            int start = Math.min(mPreviousViewHolder.getAdapterPosition() + 1, viewHolder.getAdapterPosition());
+            int end = Math.max(mPreviousViewHolder.getAdapterPosition() + 1, viewHolder.getAdapterPosition());
+            for (int i = start; i <= end; i++) {
+                mRangeSelection.add(rv.findViewHolderForAdapterPosition(i));
+            }
+            mListener.onMultipleViewHoldersSelected(rv, mRangeSelection);
+        }
+    }
+
+
+    @Override
+    public void onTouchEvent(RecyclerView rv, MotionEvent e) {
+        if (e.getAction() == MotionEvent.ACTION_UP || e.getAction() == MotionEvent.ACTION_POINTER_UP) {
+            cancelPreviousSelection();
+        } else if (mViewHolderLongPressed != null) {
+            onActionMove(rv, e);
+        }
+    }
+
+    @Override
+    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
+
+    }
+}

library-extensions/src/main/java/com/mikepenz/fastadapter_extensions/drag/LongPressItemTouchListener.java

@@ -0,0 +1,60 @@
+package com.mikepenz.fastadapter_extensions.drag;
+
+import android.content.Context;
+import android.support.v7.widget.RecyclerView;
+import android.view.GestureDetector;
+import android.view.MotionEvent;
+import android.view.View;
+
+public abstract class LongPressItemTouchListener extends RecyclerView.SimpleOnItemTouchListener {
+
+    private final GestureDetector mGestureDetector;
+    protected final OnItemInteractionListener mListener;
+    protected RecyclerView.ViewHolder mViewHolderLongPressed;
+    public RecyclerView.ViewHolder mViewHolderInFocus;
+
+    public LongPressItemTouchListener(Context context, OnItemInteractionListener listener) {
+        mGestureDetector = new GestureDetector(context, new LongPressGestureListener());
+        mGestureDetector.setIsLongpressEnabled(true);
+        mListener = listener;
+    }
+
+
+    public boolean onLongPressedEvent(RecyclerView rv, MotionEvent e) {
+
+        if (mViewHolderLongPressed != null) {
+            return false;
+            // long pressed happened, my job here is done.
+        }
+        View childViewUnder = rv.findChildViewUnder(e.getX(), e.getY());
+        if (childViewUnder != null) {
+            mViewHolderInFocus = rv.findContainingViewHolder(childViewUnder);
+            if (mGestureDetector.onTouchEvent(e) && mListener != null) {
+                mListener.onItemClicked(rv, mViewHolderInFocus, rv.getChildAdapterPosition(childViewUnder));
+            }
+            return mViewHolderLongPressed != null;
+        }
+        return false;
+    }
+
+    class LongPressGestureListener extends GestureDetector.SimpleOnGestureListener {
+        @Override
+        public boolean onSingleTapUp(MotionEvent e) {
+            return true;
+        }
+
+        @Override
+        public boolean onSingleTapConfirmed(MotionEvent e) {
+            return true;
+        }
+
+        @Override
+        public void onLongPress(MotionEvent e) {
+            if (mViewHolderInFocus != null && mListener != null) {
+                RecyclerView recyclerView = (RecyclerView) mViewHolderInFocus.itemView.getParent();
+                mListener.onLongItemClicked(recyclerView, mViewHolderInFocus, mViewHolderInFocus.getAdapterPosition());
+                mViewHolderLongPressed = mViewHolderInFocus;
+            }
+        }
+    }
+}

library-extensions/src/main/java/com/mikepenz/fastadapter_extensions/drag/OnItemInteractionListener.java

@@ -0,0 +1,15 @@
+package com.mikepenz.fastadapter_extensions.drag;
+
+import android.support.v7.widget.RecyclerView;
+
+import java.util.List;
+
+public interface OnItemInteractionListener {
+    void onLongItemClicked(RecyclerView recyclerView, RecyclerView.ViewHolder mViewHolderTouched, int position);
+
+    void onItemClicked(RecyclerView recyclerView, RecyclerView.ViewHolder mViewHolderTouched, int position);
+
+    void onViewHolderHovered(RecyclerView rv, RecyclerView.ViewHolder viewHolder);
+
+    void onMultipleViewHoldersSelected(RecyclerView rv, List<RecyclerView.ViewHolder> selection);
+}