private void recomputePhotoAndScrollingMetrics() {
mHeaderHeightPixels = mHeaderBox.getHeight();
mPhotoHeightPixels = 0;
if (mHasPhoto) {
mPhotoHeightPixels = (int) (mPhotoView.getWidth() / PHOTO_ASPECT_RATIO);
mPhotoHeightPixels = Math.min(mPhotoHeightPixels, mScrollView.getHeight() * 2 / 3);
}
ViewGroup.LayoutParams lp;
lp = mPhotoViewContainer.getLayoutParams();
if (lp.height != mPhotoHeightPixels) {
lp.height = mPhotoHeightPixels;
mPhotoViewContainer.setLayoutParams(lp);
}
ViewGroup.MarginLayoutParams mlp =
(ViewGroup.MarginLayoutParams) mDetailsContainer.getLayoutParams();
if (mlp.topMargin != mHeaderHeightPixels + mPhotoHeightPixels) {
mlp.topMargin = mHeaderHeightPixels + mPhotoHeightPixels;
mDetailsContainer.setLayoutParams(mlp);
}
onScrollChanged(0, 0); // trigger scroll handling
}
private void initViews() {
mFABElevation = getResources().getDimensionPixelSize(R.dimen.fab_elevation);
mMaxHeaderElevation =
getResources().getDimensionPixelSize(R.dimen.session_detail_max_header_elevation);
mScrollView = (ObservableScrollView) getActivity().findViewById(R.id.scroll_view);
mScrollView.addCallbacks(this);
ViewTreeObserver vto = mScrollView.getViewTreeObserver();
if (vto.isAlive()) {
vto.addOnGlobalLayoutListener(mGlobalLayoutListener);
}
mScrollViewChild = getActivity().findViewById(R.id.scroll_view_child);
mScrollViewChild.setVisibility(View.INVISIBLE);
mDetailsContainer = getActivity().findViewById(R.id.details_container);
mHeaderBox = getActivity().findViewById(R.id.header_session);
mTitle = (TextView) getActivity().findViewById(R.id.session_title);
mSubtitle = (TextView) getActivity().findViewById(R.id.session_subtitle);
mPhotoViewContainer = getActivity().findViewById(R.id.session_photo_container);
mPhotoView = (ImageView) getActivity().findViewById(R.id.session_photo);
mAbstract = (TextView) getActivity().findViewById(R.id.session_abstract);
mPlusOneIcon = (ImageView) getActivity().findViewById(R.id.gplus_icon_box);
mTwitterIcon = (ImageView) getActivity().findViewById(R.id.twitter_icon_box);
// Find view that shows a Videocam icon if the session is being live streamed.
mLiveStreamVideocamIconAndText =
(TextView) getActivity().findViewById(R.id.live_stream_videocam_icon_and_text);
// Find view that shows a play button and some text for the user to watch the session live
// stream.
mLiveStreamPlayIconAndText =
(TextView) getActivity().findViewById(R.id.live_stream_play_icon_and_text);
mRequirements = (TextView) getActivity().findViewById(R.id.session_requirements);
mTags = (LinearLayout) getActivity().findViewById(R.id.session_tags);
mTagsContainer = (ViewGroup) getActivity().findViewById(R.id.session_tags_container);
ViewCompat.setTransitionName(mPhotoView, SessionDetailConstants.TRANSITION_NAME_PHOTO);
mAddScheduleButtonContainer = getActivity().findViewById(R.id.add_schedule_button_container);
mAddScheduleButton =
(CheckableFloatingActionButton) getActivity().findViewById(R.id.add_schedule_button);
mNoPlaceholderImageLoader = new ImageLoader(getContext());
mSpeakersImageLoader = new ImageLoader(getContext(), R.drawable.person_image_empty);
}
@Override
public void onScrollChanged(int deltaX, int deltaY) {
// Reposition the header bar -- it's normally anchored to the top of the content,
// but locks to the top of the screen on scroll
int scrollY = mScrollView.getScrollY();
float newTop = Math.max(mPhotoHeightPixels, scrollY);
mHeaderBox.setTranslationY(newTop);
mAddScheduleButtonContainer.setTranslationY(
newTop + mHeaderHeightPixels - mAddScheduleButtonContainerHeightPixels / 2);
float gapFillProgress = 1;
if (mPhotoHeightPixels != 0) {
gapFillProgress =
Math.min(Math.max(UIUtils.getProgress(scrollY, 0, mPhotoHeightPixels), 0), 1);
}
ViewCompat.setElevation(mHeaderBox, gapFillProgress * mMaxHeaderElevation);
ViewCompat.setElevation(
mAddScheduleButtonContainer, gapFillProgress * mMaxHeaderElevation + mFABElevation);
ViewCompat.setElevation(
mAddScheduleButton, gapFillProgress * mMaxHeaderElevation + mFABElevation);
// Move background photo (parallax effect)
mPhotoViewContainer.setTranslationY(scrollY * 0.5f);
}
@Override
public void onDestroy() {
super.onDestroy();
if (mScrollView == null) {
return;
}
ViewTreeObserver vto = mScrollView.getViewTreeObserver();
if (vto.isAlive()) {
vto.removeGlobalOnLayoutListener(mGlobalLayoutListener);
}
}
