library/src/com/handmark/pulltorefresh/library/PullToRefreshBase.java
private void pullEvent() {
		final int newScrollValue;
		final int itemDimension;
		final float initialMotionValue, lastMotionValue;

		switch (getPullToRefreshScrollDirection()) {
			case HORIZONTAL:
				initialMotionValue = mInitialMotionX;
				lastMotionValue = mLastMotionX;
				break;
			case VERTICAL:
			default:
				initialMotionValue = mInitialMotionY;
				lastMotionValue = mLastMotionY;
				break;
		}

		switch (mCurrentMode) {
			case PULL_FROM_END:
				newScrollValue = Math.round(Math.max(initialMotionValue - lastMotionValue, 0) / FRICTION);
				itemDimension = getFooterSize();
				break;
			case PULL_FROM_START:
			default:
				newScrollValue = Math.round(Math.min(initialMotionValue - lastMotionValue, 0) / FRICTION);
				itemDimension = getHeaderSize();
				break;
		}

		setHeaderScroll(newScrollValue);

		if (newScrollValue != 0 && !isRefreshing()) {
			float scale = Math.abs(newScrollValue) / (float) itemDimension;
			switch (mCurrentMode) {
				case PULL_FROM_END:
					mFooterLayout.onPull(scale);
					break;
				case PULL_FROM_START:
				default:
					mHeaderLayout.onPull(scale);
					break;
			}

			if (mState != State.PULL_TO_REFRESH && itemDimension >= Math.abs(newScrollValue)) {
				setState(State.PULL_TO_REFRESH);
			} else if (mState == State.PULL_TO_REFRESH && itemDimension < Math.abs(newScrollValue)) {
				setState(State.RELEASE_TO_REFRESH);
			}
		}
	}
private void pullEvent() {
		final int newScrollValue;
		final int itemDimension;
		final float initialMotionValue, lastMotionValue;

		switch (getPullToRefreshScrollDirection()) {
			case HORIZONTAL:
				initialMotionValue = mInitialMotionX;
				lastMotionValue = mLastMotionX;
				break;
			case VERTICAL:
			default:
				initialMotionValue = mInitialMotionY;
				lastMotionValue = mLastMotionY;
				break;
		}

		switch (mCurrentMode) {
			case PULL_FROM_END:
				newScrollValue = Math.round(Math.max(initialMotionValue - lastMotionValue, 0) / FRICTION);
				itemDimension = getFooterSize();
				break;
			case PULL_FROM_START:
			default:
				newScrollValue = Math.round(Math.min(initialMotionValue - lastMotionValue, 0) / FRICTION);
				itemDimension = getHeaderSize();
				break;
		}

		setHeaderScroll(newScrollValue);

		if (newScrollValue != 0 && !isRefreshing()) {
			float scale = Math.abs(newScrollValue) / (float) itemDimension;
			switch (mCurrentMode) {
				case PULL_FROM_END:
					mFooterLayout.onPull(scale);
					break;
				case PULL_FROM_START:
				default:
					mHeaderLayout.onPull(scale);
					break;
			}

			if (mState != State.PULL_TO_REFRESH && itemDimension >= Math.abs(newScrollValue)) {
				setState(State.PULL_TO_REFRESH);
			} else if (mState == State.PULL_TO_REFRESH && itemDimension < Math.abs(newScrollValue)) {
				setState(State.RELEASE_TO_REFRESH);
			}
		}
	}
Actions a Pull Event

@return true if the Event has been handled, false if there has been no
change