content: /*
   * Copyright (C) 2010 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.lb.launcher;
  
  import android.content.Context;
  import android.util.AttributeSet;
  import android.view.MotionEvent;
  import android.view.View;
  
  
  /* Class that does most of the work of enabling dragging items out of a PagedView by performing a
   * vertical drag. Used by both CustomizePagedView and AllAppsPagedView.
   * Subclasses must do the following:
   *   * call setDragSlopeThreshold after making an instance of the PagedViewWithDraggableItems
   *   * call child.setOnLongClickListener(this) and child.setOnTouchListener(this) on all children
   *       (good place to do it is in syncPageItems)
   *   * override beginDragging(View) (but be careful to call super.beginDragging(View)
   *
   */
  public abstract class PagedViewWithDraggableItems extends PagedView
      implements View.OnLongClickListener, View.OnTouchListener {
      private View mLastTouchedItem;
      private boolean mIsDragging;
      private boolean mIsDragEnabled;
      private float mDragSlopeThreshold;
      private Launcher mLauncher;
  
      public PagedViewWithDraggableItems(Context context) {
          this(context, null);
      }
  
      public PagedViewWithDraggableItems(Context context, AttributeSet attrs) {
          this(context, attrs, 0);
      }
  
      public PagedViewWithDraggableItems(Context context, AttributeSet attrs, int defStyle) {
          super(context, attrs, defStyle);
          mLauncher = (Launcher) context;
      }
  
      protected boolean beginDragging(View v) {
          boolean wasDragging = mIsDragging;
          mIsDragging = true;
          return !wasDragging;
      }
  
      protected void cancelDragging() {
          mIsDragging = false;
          mLastTouchedItem = null;
          mIsDragEnabled = false;
      }
  
      private void handleTouchEvent(MotionEvent ev) {
          final int action = ev.getAction();
          switch (action & MotionEvent.ACTION_MASK) {
              case MotionEvent.ACTION_DOWN:
                  cancelDragging();
                  mIsDragEnabled = true;
                  break;
              case MotionEvent.ACTION_MOVE:
                  if (mTouchState != TOUCH_STATE_SCROLLING && !mIsDragging && mIsDragEnabled) {
                      determineDraggingStart(ev);
                  }
                  break;
          }
      }
  
      @Override
      public boolean onInterceptTouchEvent(MotionEvent ev) {
          handleTouchEvent(ev);
          return super.onInterceptTouchEvent(ev);
      }
  
      @Override
      public boolean onTouchEvent(MotionEvent ev) {
          handleTouchEvent(ev);
          return super.onTouchEvent(ev);
      }
  
      public void trimMemory() {
          mLastTouchedItem = null;
      }
  
      @Override
      public boolean onTouch(View v, MotionEvent event) {
          mLastTouchedItem = v;
          mIsDragEnabled = true;
          return false;
      }
  
      @Override
      public boolean onLongClick(View v) {
          // Return early if this is not initiated from a touch
          if (!v.isInTouchMode()) return false;
          // Return early if we are still animating the pages
          if (mNextPage != INVALID_PAGE) return false;
          // When we have exited all apps or are in transition, disregard long clicks
          if (!mLauncher.isAllAppsVisible() ||
                  mLauncher.getWorkspace().isSwitchingState()) return false;
          // Return if global dragging is not enabled
          if (!mLauncher.isDraggingEnabled()) return false;
  
          return beginDragging(v);
      }
  
      /*
       * Determines if we should change the touch state to start scrolling after the
       * user moves their touch point too far.
       */
      protected void determineScrollingStart(MotionEvent ev) {
          if (!mIsDragging) super.determineScrollingStart(ev);
      }
  
      /*
       * Determines if we should change the touch state to start dragging after the
       * user moves their touch point far enough.
       */
      protected void determineDraggingStart(MotionEvent ev) {
          /*
           * Locally do absolute value. mLastMotionX is set to the y value
           * of the down event.
           */
          final int pointerIndex = ev.findPointerIndex(mActivePointerId);
          final float x = ev.getX(pointerIndex);
          final float y = ev.getY(pointerIndex);
          final int xDiff = (int) Math.abs(x - mLastMotionX);
          final int yDiff = (int) Math.abs(y - mLastMotionY);
  
          final int touchSlop = mTouchSlop;
          boolean yMoved = yDiff > touchSlop;
          boolean isUpwardMotion = (yDiff / (float) xDiff) > mDragSlopeThreshold;
  
          if (isUpwardMotion && yMoved && mLastTouchedItem != null) {
              // Drag if the user moved far enough along the Y axis
              beginDragging(mLastTouchedItem);
  
              // Cancel any pending long press
              if (mAllowLongPress) {
                  mAllowLongPress = false;
                  // Try canceling the long press. It could also have been scheduled
                  // by a distant descendant, so use the mAllowLongPress flag to block
                  // everything
                  final View currentPage = getPageAt(mCurrentPage);
                  if (currentPage != null) {
                      currentPage.cancelLongPress();
                  }
              }
          }
      }
  
      public void setDragSlopeThreshold(float dragSlopeThreshold) {
          mDragSlopeThreshold = dragSlopeThreshold;
      }
  
      @Override
      protected void onDetachedFromWindow() {
          cancelDragging();
          super.onDetachedFromWindow();
      }
  }
  