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platform_packages_apps_Launcher3
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Address bug 2631580 - Tweak home screen scrolling behavior. 

Duration of motion is now influenced by fling velocity. Constants have
been tuned and tweaked.

Fix a couple of drawing optimizations in Launcher2 Workspace.

Change-Id: Iaa674d10a28554884d9cc98134b2d1253b5e3e70
This commit is contained in:
Adam Powell 2010-04-26 16:43:44 -07:00
parent 2762dd856e
commit d40613a693
1 changed files with 51 additions and 31 deletions
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82
src/com/android/launcher2/Workspace.java
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@ -121,8 +121,11 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
private WorkspaceOvershootInterpolator mScrollInterpolator;
private static final float BASELINE_FLING_VELOCITY = 2500.f;
private static final float FLING_VELOCITY_INFLUENCE = 0.4f;
private static class WorkspaceOvershootInterpolator implements Interpolator {
private static final float DEFAULT_TENSION = 2.f;
private static final float DEFAULT_TENSION = 1.3f;
private float mTension;
public WorkspaceOvershootInterpolator() {
@ -133,6 +136,10 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
mTension = distance > 0 ? DEFAULT_TENSION / distance : DEFAULT_TENSION;
}
public void disableSettle() {
mTension = 0.f;
}
public float getInterpolation(float t) {
// _o(t) = t * t * ((tension + 1) * t + tension)
// o(t) = _o(t - 1) + 1
@ -452,17 +459,14 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
drawChild(canvas, getChildAt(mCurrentScreen), getDrawingTime());
} else {
final long drawingTime = getDrawingTime();
// If we are flinging, draw only the current screen and the target screen
if (mNextScreen >= 0 && mNextScreen < getChildCount() &&
Math.abs(mCurrentScreen - mNextScreen) == 1) {
drawChild(canvas, getChildAt(mCurrentScreen), drawingTime);
drawChild(canvas, getChildAt(mNextScreen), drawingTime);
} else {
// If we are scrolling, draw all of our children
final int count = getChildCount();
for (int i = 0; i < count; i++) {
drawChild(canvas, getChildAt(i), drawingTime);
}
final float scrollPos = (float) mScrollX / getWidth();
final int leftScreen = (int) scrollPos;
final int rightScreen = leftScreen + 1;
if (leftScreen >= 0) {
drawChild(canvas, getChildAt(leftScreen), drawingTime);
}
if (scrollPos != leftScreen && rightScreen < getChildCount()) {
drawChild(canvas, getChildAt(rightScreen), drawingTime);
}
}
@ -780,8 +784,11 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
void enableChildrenCache(int fromScreen, int toScreen) {
if (fromScreen > toScreen) {
fromScreen = toScreen;
toScreen = fromScreen;
final int temp = fromScreen;
fromScreen = toScreen - 1;
toScreen = temp;
} else {
toScreen++;
}
final int count = getChildCount();
@ -880,15 +887,15 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
// Don't fling across more than one screen at a time.
final int bound = scrolledPos < whichScreen ?
mCurrentScreen - 1 : mCurrentScreen;
snapToScreen(Math.min(whichScreen, bound));
snapToScreen(Math.min(whichScreen, bound), velocityX, true);
} else if (velocityX < -SNAP_VELOCITY && mCurrentScreen < getChildCount() - 1) {
// Fling hard enough to move right
// Don't fling across more than one screen at a time.
final int bound = scrolledPos > whichScreen ?
mCurrentScreen + 1 : mCurrentScreen;
snapToScreen(Math.max(whichScreen, bound));
snapToScreen(Math.max(whichScreen, bound), velocityX, true);
} else {
snapToDestination();
snapToScreen(whichScreen, 0, true);
}
if (mVelocityTracker != null) {
@ -910,15 +917,12 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
return true;
}
private void snapToDestination() {
final int screenWidth = getWidth();
final int whichScreen = (mScrollX + (screenWidth / 2)) / screenWidth;
snapToScreen(whichScreen);
void snapToScreen(int whichScreen) {
snapToScreen(whichScreen, 0, false);
}
void snapToScreen(int whichScreen) {
private void snapToScreen(int whichScreen, int velocity, boolean settle) {
//if (!mScroller.isFinished()) return;
whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1));
@ -926,25 +930,41 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
clearVacantCache();
enableChildrenCache(mCurrentScreen, whichScreen);
final int screenDelta = Math.abs(whichScreen - mCurrentScreen);
mNextScreen = whichScreen;
mPreviousIndicator.setLevel(mNextScreen);
mNextIndicator.setLevel(mNextScreen);
View focusedChild = getFocusedChild();
if (focusedChild != null && screenDelta != 0 && focusedChild == getChildAt(mCurrentScreen)) {
if (focusedChild != null && whichScreen != mCurrentScreen &&
focusedChild == getChildAt(mCurrentScreen)) {
focusedChild.clearFocus();
}
final int screenDelta = Math.max(1, Math.abs(whichScreen - mCurrentScreen));
final int newX = whichScreen * getWidth();
final int delta = newX - mScrollX;
final int duration = screenDelta != 0 ? 200 + screenDelta * 100 : 300;
awakenScrollBars(duration);
int duration = (screenDelta + 1) * 100;
if (!mScroller.isFinished()) mScroller.abortAnimation();
mScrollInterpolator.setDistance(screenDelta);
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
if (settle) {
mScrollInterpolator.setDistance(screenDelta);
} else {
mScrollInterpolator.disableSettle();
}
velocity = Math.abs(velocity);
if (velocity > 0) {
duration += (duration / (velocity / BASELINE_FLING_VELOCITY))
* FLING_VELOCITY_INFLUENCE;
} else {
duration += 100;
}
awakenScrollBars(duration);
mScroller.startScroll(mScrollX, 0, delta, 0, duration);
invalidate();
}