content: /*
   * Copyright (C) 2018 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.android.launcher3.allapps;
  
  import android.content.Context;
  import android.util.AttributeSet;
  import android.view.MotionEvent;
  
  import com.android.launcher3.PagedView;
  
  public class AllAppsPagedView extends PagedView<PersonalWorkSlidingTabStrip> {
  
    final static float START_DAMPING_TOUCH_SLOP_ANGLE = (float) Math.PI / 6;
    final static float MAX_SWIPE_ANGLE = (float) Math.PI / 3;
    final static float TOUCH_SLOP_DAMPING_FACTOR = 4;
  
    public AllAppsPagedView(Context context) {
          this(context, null);
      }
  
      public AllAppsPagedView(Context context, AttributeSet attrs) {
          this(context, attrs, 0);
      }
  
      public AllAppsPagedView(Context context, AttributeSet attrs, int defStyle) {
          super(context, attrs, defStyle);
      }
  
      @Override
      protected String getCurrentPageDescription() {
          // Not necessary, tab-bar already has two tabs with their own descriptions.
          return "";
      }
  
      @Override
      protected void onScrollChanged(int l, int t, int oldl, int oldt) {
          super.onScrollChanged(l, t, oldl, oldt);
          mPageIndicator.setScroll(l, mMaxScrollX);
      }
  
      @Override
      protected void determineScrollingStart(MotionEvent ev) {
          float absDeltaX = Math.abs(ev.getX() - getDownMotionX());
          float absDeltaY = Math.abs(ev.getY() - getDownMotionY());
  
          if (Float.compare(absDeltaX, 0f) == 0) return;
  
          float slope = absDeltaY / absDeltaX;
          float theta = (float) Math.atan(slope);
  
          if (absDeltaX > mTouchSlop || absDeltaY > mTouchSlop) {
              cancelCurrentPageLongPress();
          }
  
          if (theta > MAX_SWIPE_ANGLE) {
              return;
          } else if (theta > START_DAMPING_TOUCH_SLOP_ANGLE) {
              theta -= START_DAMPING_TOUCH_SLOP_ANGLE;
              float extraRatio = (float)
                      Math.sqrt((theta / (MAX_SWIPE_ANGLE - START_DAMPING_TOUCH_SLOP_ANGLE)));
              super.determineScrollingStart(ev, 1 + TOUCH_SLOP_DAMPING_FACTOR * extraRatio);
          } else {
              super.determineScrollingStart(ev);
          }
      }
  
      @Override
      public boolean hasOverlappingRendering() {
          return false;
      }
  
      @Override
      protected boolean isVerticalScrollable() {
          return false;
      }
  }
  