private void animateOffsetToCorrectPosition() {
mFrom = mCurrentOffsetTop;
mFromDragPercent = mCurrentDragPercent;
mAnimateToCorrectPosition.reset();
mAnimateToCorrectPosition.setDuration(MAX_OFFSET_ANIMATION_DURATION);
mAnimateToCorrectPosition.setInterpolator(mDecelerateInterpolator);
mRefreshView.clearAnimation();
mRefreshView.startAnimation(mAnimateToCorrectPosition);
if (mRefreshing) {
mBaseRefreshView.start();
if (mNotify) {
if (mListener != null) {
mListener.onRefresh();
}
}
} else {
mBaseRefreshView.stop();
animateOffsetToStartPosition();
}
mCurrentOffsetTop = mTarget.getTop();
mTarget.setPadding(
mTargetPaddingLeft, mTargetPaddingTop, mTargetPaddingRight, mTotalDragDistance);
}
private void setTargetOffsetTop(int offset, boolean requiresUpdate) {
mTarget.offsetTopAndBottom(offset);
mBaseRefreshView.offsetTopAndBottom(offset);
mCurrentOffsetTop = mTarget.getTop();
if (requiresUpdate && android.os.Build.VERSION.SDK_INT < 11) {
invalidate();
}
}
@Override
public void applyTransformation(float interpolatedTime, Transformation t) {
int targetTop;
int endTarget = mTotalDragDistance;
targetTop = (mFrom + (int) ((endTarget - mFrom) * interpolatedTime));
int offset = targetTop - mTarget.getTop();
mCurrentDragPercent = mFromDragPercent - (mFromDragPercent - 1.0f) * interpolatedTime;
mBaseRefreshView.setPercent(mCurrentDragPercent, false);
setTargetOffsetTop(offset, false /* requires update */);
}
private void setRefreshing(boolean refreshing, final boolean notify) {
if (mRefreshing != refreshing) {
mNotify = notify;
ensureTarget();
mRefreshing = refreshing;
if (mRefreshing) {
mBaseRefreshView.setPercent(1f, true);
animateOffsetToCorrectPosition();
} else {
animateOffsetToStartPosition();
}
}
}
private void moveToStart(float interpolatedTime) {
int targetTop = mFrom - (int) (mFrom * interpolatedTime);
float targetPercent = mFromDragPercent * (1.0f - interpolatedTime);
int offset = targetTop - mTarget.getTop();
mCurrentDragPercent = targetPercent;
mBaseRefreshView.setPercent(mCurrentDragPercent, true);
mTarget.setPadding(
mTargetPaddingLeft,
mTargetPaddingTop,
mTargetPaddingRight,
mTargetPaddingBottom + targetTop);
setTargetOffsetTop(offset, false);
}
@Override
public void onAnimationEnd(Animation animation) {
mBaseRefreshView.stop();
mCurrentOffsetTop = mTarget.getTop();
}
@Override
public boolean onTouchEvent(@NonNull MotionEvent ev) {
if (!mIsBeingDragged) {
return super.onTouchEvent(ev);
}
final int action = MotionEventCompat.getActionMasked(ev);
switch (action) {
case MotionEvent.ACTION_MOVE:
{
final int pointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
if (pointerIndex < 0) {
return false;
}
final float y = MotionEventCompat.getY(ev, pointerIndex);
final float yDiff = y - mInitialMotionY;
final float scrollTop = yDiff * DRAG_RATE;
mCurrentDragPercent = scrollTop / mTotalDragDistance;
if (mCurrentDragPercent < 0) {
return false;
}
float boundedDragPercent = Math.min(1f, Math.abs(mCurrentDragPercent));
float extraOS = Math.abs(scrollTop) - mTotalDragDistance;
float slingshotDist = mTotalDragDistance;
float tensionSlingshotPercent =
Math.max(0, Math.min(extraOS, slingshotDist * 2) / slingshotDist);
float tensionPercent =
(float) ((tensionSlingshotPercent / 4) - Math.pow((tensionSlingshotPercent / 4), 2))
* 2f;
float extraMove = (slingshotDist) * tensionPercent / 2;
int targetY = (int) ((slingshotDist * boundedDragPercent) + extraMove);
mBaseRefreshView.setPercent(mCurrentDragPercent, true);
setTargetOffsetTop(targetY - mCurrentOffsetTop, true);
break;
}
case MotionEventCompat.ACTION_POINTER_DOWN:
final int index = MotionEventCompat.getActionIndex(ev);
mActivePointerId = MotionEventCompat.getPointerId(ev, index);
break;
case MotionEventCompat.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
{
if (mActivePointerId == INVALID_POINTER) {
return false;
}
final int pointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
final float y = MotionEventCompat.getY(ev, pointerIndex);
final float overScrollTop = (y - mInitialMotionY) * DRAG_RATE;
mIsBeingDragged = false;
if (overScrollTop > mTotalDragDistance) {
setRefreshing(true, true);
} else {
mRefreshing = false;
animateOffsetToStartPosition();
}
mActivePointerId = INVALID_POINTER;
return false;
}
}
return true;
}