Adding overscroll to Workspace, AllApps and Customize

-Also modified the background alpha interpolation during scrolling

Change-Id: I68db8fbe80f720c507ab3208d8b3dcd8aa4f2081

3 files changed, 101 insertions, 41 deletions

diff --git a/src/com/android/launcher2/PagedView.java b/src/com/android/launcher2/PagedView.java
index fb8b7d64d..a2ed9858a 100644
--- a/src/com/android/launcher2/PagedView.java
+++ b/src/com/android/launcher2/PagedView.java
@@ -27,7 +27,6 @@ import android.graphics.Rect;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.util.AttributeSet;
-import android.util.Log;
 import android.view.ActionMode;
 import android.view.MotionEvent;
 import android.view.VelocityTracker;
@@ -36,10 +35,9 @@ import android.view.ViewConfiguration;
 import android.view.ViewGroup;
 import android.view.ViewParent;
 import android.view.animation.Animation;
-import android.view.animation.Animation.AnimationListener;
 import android.view.animation.AnimationUtils;
+import android.view.animation.Animation.AnimationListener;
 import android.widget.Checkable;
-import android.widget.LinearLayout;
 import android.widget.Scroller;
 
 import com.android.launcher.R;
@@ -60,6 +58,8 @@ public abstract class PagedView extends ViewGroup {
     private static final int PAGE_SNAP_ANIMATION_DURATION = 750;
     protected static final float NANOTIME_DIV = 1000000000.0f;
 
+    private static final float OVERSCROLL_DAMP_FACTOR = 0.22f;
+
     // the velocity at which a fling gesture will cause us to snap to the next page
     protected int mSnapVelocity = 500;
 
@@ -70,6 +70,7 @@ public abstract class PagedView extends ViewGroup {
 
     protected int mCurrentPage;
     protected int mNextPage = INVALID_PAGE;
+    protected int mMaxScrollX;
     protected Scroller mScroller;
     private VelocityTracker mVelocityTracker;
 
@@ -103,6 +104,8 @@ public abstract class PagedView extends ViewGroup {
     protected int mCellCountX;
     protected int mCellCountY;
     protected boolean mCenterPagesVertically;
+    protected boolean mAllowOverScroll = true;
+    protected int mUnboundedScrollX;
 
     protected static final int INVALID_POINTER = -1;
 
@@ -312,8 +315,28 @@ public abstract class PagedView extends ViewGroup {
     }
 
     @Override
+    public void scrollBy(int x, int y) {
+        scrollTo(mUnboundedScrollX + x, mScrollY + y);
+    }
+
+    @Override
     public void scrollTo(int x, int y) {
-        super.scrollTo(x, y);
+        mUnboundedScrollX = x;
+
+        if (x < 0) {
+            super.scrollTo(0, y);
+            if (mAllowOverScroll) {
+                overScroll(x);
+            }
+        } else if (x > mMaxScrollX) {
+            super.scrollTo(mMaxScrollX, y);
+            if (mAllowOverScroll) {
+                overScroll(x - mMaxScrollX);
+            }
+        } else {
+            super.scrollTo(x, y);
+        }
+
         mTouchX = x;
         mSmoothingTime = System.nanoTime() / NANOTIME_DIV;
     }
@@ -395,6 +418,7 @@ public abstract class PagedView extends ViewGroup {
             heightSize = maxChildHeight + verticalPadding;
         }
 
+        mMaxScrollX = getChildOffset(childCount - 1) - getRelativeChildOffset(childCount - 1);
         setMeasuredDimension(widthSize, heightSize);
     }
 
@@ -799,6 +823,16 @@ public abstract class PagedView extends ViewGroup {
         return false;
     }
 
+    protected void overScroll(float amount) {
+        int overScrollAmount = (int) Math.round(OVERSCROLL_DAMP_FACTOR * amount);
+        if (amount < 0) {
+            mScrollX = overScrollAmount;
+        } else {
+            mScrollX = mMaxScrollX + overScrollAmount;
+        }
+        invalidate();
+    }
+
     @Override
     public boolean onTouchEvent(MotionEvent ev) {
         // Skip touch handling if there are no pages to swipe
@@ -834,31 +868,13 @@ public abstract class PagedView extends ViewGroup {
                 final int deltaX = (int) (mLastMotionX - x);
                 mLastMotionX = x;
 
-                int sx = getScrollX();
-                if (deltaX < 0) {
-                    if (sx > 0) {
-                        mTouchX += Math.max(-mTouchX, deltaX);
-                        mSmoothingTime = System.nanoTime() / NANOTIME_DIV;
-                        if (!mDeferScrollUpdate) {
-                            scrollBy(Math.max(-sx, deltaX), 0);
-                        } else {
-                            // This will trigger a call to computeScroll() on next drawChild() call
-                            invalidate();
-                        }
-                    }
-                } else if (deltaX > 0) {
-                    final int lastChildIndex = getChildCount() - 1;
-                    final int availableToScroll = getChildOffset(lastChildIndex) -
-                        getRelativeChildOffset(lastChildIndex) - sx;
-                    if (availableToScroll > 0) {
-                        mTouchX += Math.min(availableToScroll, deltaX);
-                        mSmoothingTime = System.nanoTime() / NANOTIME_DIV;
-                        if (!mDeferScrollUpdate) {
-                            scrollBy(Math.min(availableToScroll, deltaX), 0);
-                        } else {
-                            // This will trigger a call to computeScroll() on next drawChild() call
-                            invalidate();
-                        }
+                if (deltaX != 0) {
+                    mTouchX += deltaX;
+                    mSmoothingTime = System.nanoTime() / NANOTIME_DIV;
+                    if (!mDeferScrollUpdate) {
+                        scrollBy(deltaX, 0);
+                    } else {
+                        invalidate();
                     }
                 } else {
                     awakenScrollBars();
@@ -1042,7 +1058,7 @@ public abstract class PagedView extends ViewGroup {
         whichPage = Math.max(0, Math.min(whichPage, getPageCount() - 1));
 
         int newX = getChildOffset(whichPage) - getRelativeChildOffset(whichPage);
-        final int sX = getScrollX();
+        final int sX = mUnboundedScrollX;
         final int delta = newX - sX;
         snapToPage(whichPage, delta, duration);
     }
@@ -1063,7 +1079,7 @@ public abstract class PagedView extends ViewGroup {
         }
 
         if (!mScroller.isFinished()) mScroller.abortAnimation();
-        mScroller.startScroll(getScrollX(), 0, delta, 0, duration);
+        mScroller.startScroll(mUnboundedScrollX, 0, delta, 0, duration);
 
         // only load some associated pages
         loadAssociatedPages(mNextPage);
diff --git a/src/com/android/launcher2/SmoothPagedView.java b/src/com/android/launcher2/SmoothPagedView.java
index 8e729e431..ee8bca20e 100644
--- a/src/com/android/launcher2/SmoothPagedView.java
+++ b/src/com/android/launcher2/SmoothPagedView.java
@@ -138,7 +138,7 @@ public abstract class SmoothPagedView extends PagedView {
 
         final int screenDelta = Math.max(1, Math.abs(whichPage - mCurrentPage));
         final int newX = getChildOffset(whichPage) - getRelativeChildOffset(whichPage);
-        final int delta = newX - mScrollX;
+        final int delta = newX - mUnboundedScrollX;
         int duration;
         if (mScrollMode == OVERSHOOT_MODE) {
             duration = (screenDelta + 1) * 100;
@@ -180,8 +180,9 @@ public abstract class SmoothPagedView extends PagedView {
         if (!scrollComputed && mTouchState == TOUCH_STATE_SCROLLING) {
             final float now = System.nanoTime() / NANOTIME_DIV;
             final float e = (float) Math.exp((now - mSmoothingTime) / SMOOTHING_CONSTANT);
-            final float dx = mTouchX - mScrollX;
-            mScrollX += dx * e;
+
+            final float dx = mTouchX - mUnboundedScrollX;
+            scrollTo(Math.round(mUnboundedScrollX + dx * e), mScrollY);
             mSmoothingTime = now;
 
             // Keep generating points as long as we're more than 1px away from the target
@@ -189,5 +190,6 @@ public abstract class SmoothPagedView extends PagedView {
                 invalidate();
             }
         }
+
     }
 }
diff --git a/src/com/android/launcher2/Workspace.java b/src/com/android/launcher2/Workspace.java
index 7a264e35a..69be0083f 100644
--- a/src/com/android/launcher2/Workspace.java
+++ b/src/com/android/launcher2/Workspace.java
@@ -20,14 +20,13 @@ import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
 
-import android.R.integer;
 import android.animation.Animator;
-import android.animation.Animator.AnimatorListener;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
 import android.animation.PropertyValuesHolder;
 import android.animation.TimeInterpolator;
 import android.animation.ValueAnimator;
+import android.animation.Animator.AnimatorListener;
 import android.animation.ValueAnimator.AnimatorUpdateListener;
 import android.app.AlertDialog;
 import android.app.WallpaperManager;
@@ -92,8 +91,8 @@ public class Workspace extends SmoothPagedView
     private static final float EXTRA_SCALE_FACTOR_1 = 1.0f;
     private static final float EXTRA_SCALE_FACTOR_2 = 1.10f;
 
-    private static final int CHILDREN_OUTLINE_FADE_OUT_DELAY = 300;
-    private static final int CHILDREN_OUTLINE_FADE_OUT_DURATION = 300;
+    private static final int CHILDREN_OUTLINE_FADE_OUT_DELAY = 0;
+    private static final int CHILDREN_OUTLINE_FADE_OUT_DURATION = 375;
     private static final int CHILDREN_OUTLINE_FADE_IN_DURATION = 100;
 
     private static final int BACKGROUND_FADE_OUT_DURATION = 450;
@@ -109,6 +108,7 @@ public class Workspace extends SmoothPagedView
     private ObjectAnimator mBackgroundFadeOutAnimation;
     private Drawable mBackground;
     private float mBackgroundAlpha = 0;
+    private float mOverScrollMaxBackgroundAlpha = 0.0f;
 
     private final WallpaperManager mWallpaperManager;
 
@@ -515,7 +515,7 @@ public class Workspace extends SmoothPagedView
             mAnimOnPageEndMoving.start();
             mAnimOnPageEndMoving = null;
         }
-
+        mOverScrollMaxBackgroundAlpha = 0.0f;
         mPageMoving = false;
     }
 
@@ -638,9 +638,51 @@ public class Workspace extends SmoothPagedView
         return (width - mTempFloat2[0]) * (degrees > 0.0f ? 1.0f : -1.0f);
     }
 
+    float backgroundAlphaInterpolator(float r) {
+        float pivotA = 0.1f;
+        float pivotB = 0.4f;
+        if (r < pivotA) {
+            return 0;
+        } else if (r > pivotB) {
+            return 1.0f;
+        } else {
+            return (r - pivotA)/(pivotB - pivotA);
+        }
+    }
+
+    float overScrollBackgroundAlphaInterpolator(float r) {
+        float threshold = 0.1f;
+
+        if (r > mOverScrollMaxBackgroundAlpha) {
+            mOverScrollMaxBackgroundAlpha = r;
+        } else if (r < mOverScrollMaxBackgroundAlpha) {
+            r = mOverScrollMaxBackgroundAlpha;
+        }
+
+        return Math.min(r / threshold, 1.0f);
+    }
+
+    protected void overScroll(float amount) {
+        final int lastChildIndex = getChildCount() - 1;
+
+        CellLayout cl;
+        if (amount < 0) {
+            cl = (CellLayout) getChildAt(0);
+        } else {
+            cl = (CellLayout) getChildAt(lastChildIndex);
+        }
+
+        final int totalDistance = cl.getMeasuredWidth() + mPageSpacing;
+        float r = 1.0f * amount / totalDistance;
+        float rotation = -WORKSPACE_ROTATION * r;
+        cl.setBackgroundAlphaMultiplier(overScrollBackgroundAlphaInterpolator(Math.abs(r)));
+        cl.setRotationY(rotation);
+    }
+
     @Override
     protected void screenScrolled(int screenCenter) {
         final int halfScreenSize = getMeasuredWidth() / 2;
+
         for (int i = 0; i < getChildCount(); i++) {
             CellLayout cl = (CellLayout) getChildAt(i);
             if (cl != null) {
@@ -652,11 +694,12 @@ public class Workspace extends SmoothPagedView
                 scrollProgress = Math.min(scrollProgress, 1.0f);
                 scrollProgress = Math.max(scrollProgress, -1.0f);
 
-                cl.setBackgroundAlphaMultiplier(Math.abs(scrollProgress));
+                cl.setBackgroundAlphaMultiplier(backgroundAlphaInterpolator(Math.abs(scrollProgress)));
 
                 float rotation = WORKSPACE_ROTATION * scrollProgress;
                 float translationX = getOffsetXForRotation(rotation, cl.getWidth(), cl.getHeight());
                 cl.setTranslationX(translationX);
+
                 cl.setRotationY(rotation);
             }
         }
@@ -1431,7 +1474,6 @@ public class Workspace extends SmoothPagedView
             }
         });
 
-
         view.setVisibility(View.INVISIBLE);
 
         if (!mScroller.isFinished()) {