Develop Reference

How to correctly animate stacking views one after another in Android using handler?

I have a LinearLayout with RelativeLayout children. Each RelativeLayout has a background image like a file cabinet. I am trying to animate the drawers dropping down into view one after another with a smooth delay. Everything I have tried plays all animations at once. I have this as my method for animating each drawer:
private void dropAndPause(final RelativeLayout drawer){
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
animation = AnimationUtils.loadAnimation(MainActivity.this, R.anim.slide_down);
animation.setStartOffset(750L);
drawer.startAnimation(animation);
}
}, 1200);
}
I have also tried this:
View[] views = new View[] { ... };
// 100ms delay between Animations
long delayBetweenAnimations = 100l;
for(int i = 0; i < views.length; i++) {
final View view = views[i];
// We calculate the delay for this Animation, each animation starts 100ms
// after the previous one
int delay = i * delayBetweenAnimations;
view.postDelayed(new Runnable() {
#Override
public void run() {
Animation animation = AnimationUtils.loadAnimation(context, R.anim.your_animation);
view.startAnimation(animation);
}
}, delay);
}
Instead of View[] views, I used this:
View[] drawers = new View[] {
drawerOne, drawerTwo, drawerThree, drawerFour, drawerFive
};
Which plays, again, all of the animations at once. How can I get each "drawer"/view to slide in one at a time? Also, should I have each view as visibility GONE initially?

If you want to animate the views inside a layout, then it's much easier to use layout animations. Basically, you need to load an animation, create a LayoutAnimationController, set the delay on it, and launch the animation. Here's some sample code.
Animation animation = AnimationUtils.loadAnimation(MainActivity.this, R.anim.slide_down);
animation.setStartOffset(750L);
LayoutAnimationController controller = new LayoutAnimationController(animation);
controller.setDelay(0.1F);
viewGroup.setLayoutAnimation(controller);
viewGroup.startLayoutAnimation();
The delay here is set as fraction of the animation duration.

RecyclerView - ItemAnimator -> animateChange does not work properly?

I am trying to get my head around the ItemAnimator class to be used if I want to animate the content of my RecyclerView.
Here my problem is very specific : I don't understand how the change animation works and I am not using move / add / delete animations: only change.
I've been looking to examples like the BaseItemAnimator of this project to see how it uses the SimpleItemAnimator as defined inside the android support library.
When the change animation is actually run after the method runPendingAnimation() is called I can see that there is two ViewHolders containing the same view but not exactly (I checked, different IDs, but SAME content!) and both are animated with translation and alpha values.
I tried adding my own animation, like scale to see if I get it, but no because some time it works some time it does not. I just don't understand how the RecyclerView uses his view holders when there are such animations.
Can anyone tell me how I should be using these view holders so that my own animations are played properly everytime ? I'd like to run an animation that resize the cell.
Thanks !
PS:
I use the Adapater#notifyItemChange(position) method to trigger the animation
I trigger the animation when the RecyclerView is not being scrolled
I use setSupportsChangeAnimations(true) so that change animations are triggered
EDIT 1
I'd like to show the code where I attempt to add my own animations alongside the the already existing animations. Remember, we are inside runPendingChanges().
if (changesPending) {
final List<CustomChangeInfo> changes = new ArrayList<>(this.mPendingChangesCustom.size());
changes.addAll(this.mPendingChangesCustom);
this.mPendingChangesCustom.clear();
final Runnable changer = new Runnable() {
#Override
public void run() {
for (final CustomChangeInfo customChangeInfo : changes) {
final ChangeInfo changeInfo = customChangeInfo.changeInfo;
final RecyclerView.ViewHolder holder = changeInfo.oldHolder;
final View oldView = holder == null ? null : holder.itemView;
final RecyclerView.ViewHolder newHolder = changeInfo.newHolder;
final View newView = newHolder != null ? newHolder.itemView : null;
if (oldView != null) {
mChangeAnimations.add(changeInfo.oldHolder);
final ViewPropertyAnimatorCompat oldViewAnim =
ViewCompat.animate(oldView).setDuration(2500);
oldViewAnim.scaleX(1.5f).scaleY(1.5f);
oldViewAnim.translationX(changeInfo.toX - changeInfo.fromX);
oldViewAnim.translationY(changeInfo.toY - changeInfo.fromY);
oldViewAnim.alpha(1).setListener(new VpaListenerAdapter() {
#Override public void onAnimationStart(View view) {
dispatchChangeStarting(changeInfo.oldHolder, true);
Log.d(TAG, "Start Old View id = " + view.getId());
}
#Override public void onAnimationEnd(View view) {
Log.d(TAG, "End Old View id = " + oldView.getId());
oldViewAnim.setListener(null);
ViewCompat.setAlpha(view, 1);
ViewCompat.setTranslationX(view, 0);
ViewCompat.setTranslationY(view, 0);
ViewCompat.setScaleX(view, 1f);
ViewCompat.setScaleY(view, 1f);
dispatchChangeFinished(changeInfo.oldHolder, true);
mChangeAnimations.remove(changeInfo.oldHolder);
dispatchFinishedWhenDone();
}
}).start();
}
if (newView != null) {
mChangeAnimations.add(changeInfo.newHolder);
final ViewPropertyAnimatorCompat newViewAnimation = ViewCompat.animate(newView);
newViewAnimation.translationX(0).translationY(0).setDuration(2500)
.scaleX(1.5f).scaleY(1.5f)
.alpha(1).setListener(new VpaListenerAdapter() {
#Override public void onAnimationStart(View view) {
dispatchChangeStarting(changeInfo.newHolder, false);
Log.d(TAG, "Start New View id = " + view.getId());
}
#Override public void onAnimationEnd(View view) {
Log.d(TAG, "End New View id = " + newView.getId());
newViewAnimation.setListener(null);
ViewCompat.setAlpha(newView, 1);
ViewCompat.setTranslationX(newView, 0);
ViewCompat.setTranslationY(newView, 0);
ViewCompat.setScaleX(newView, 1f);
ViewCompat.setScaleY(newView, 1f);
dispatchChangeFinished(changeInfo.newHolder, false);
mChangeAnimations.remove(changeInfo.newHolder);
dispatchFinishedWhenDone();
}
}).start();
}
}
}
};
As you see I added some log to check the IDs to see if we're working on different views here and it is indeed the case !
The results are inconsistent :
1. some time I can see two views scaling, sometime only one
2. some time it's another cell that was scaled (when I scroll after the animations)
3. some time no animations are run...

Odd behavior with RecyclerView animations using onPreDraw()

I successfully added onPreDraw animations to a RecyclerView using the following code. I call this function immediately after the adapter is set.
public void initialRVAnimation() {
rvAnims = new ViewTreeObserver.OnPreDrawListener() {
#Override
public boolean onPreDraw() {
rv.getViewTreeObserver().removeOnPreDrawListener(this);
for (int i = 0; i < rv.getChildCount(); i++) {
View v = rv.getChildAt(i);
v.setTranslationY(Utils.getScreenHeight(LiveThreadActivity.this));
v.animate()
.setStartDelay(50 * i)
.translationY(0)
.setInterpolator(new DecelerateInterpolator(3.f))
.setDuration(700)
.start();
}
return true;
}
};
rv.getViewTreeObserver().addOnPreDrawListener(rvAnims);
}
However, this causes an issue when adding items to the RecyclerView. The items seem to inherit the start delay specified in the animation and when a new item is added to the top of the RecyclerView, rather than all the items below moving down at once, they move in a staggered way. Here's a video to demonstrate the problem. Here's the normal animation when adding items when not using the onPreDraw animation.
Items are added to the RecyclerView using the following code.
public void addItem(View v) {
data.add(1, new Comment());
adapter.notifyItemInserted(1);
}

How to use swipe on different objects

I'd like to use the swipe(onFling) feature of android gestures. I have some adjacent pictures to
chancge into an other picture, in case of swiping.(Just like i demonstrated on the picture)
It should work regardless, which direction the player swipe his/her finger.
Could you give me any link? Or any idea which components should i use?

Since your gesture appears to apply the premise that it must:
Gesture must include all adjacent views.Gesture has a direct linear begginning and endGesture is a single movementGesture does not conflict with other similar gestures
You might want to read on "MotionEvent", and the onTouch listener for views.
A single flag private static View beganOn; on the parent class (I am supposing an Activity). Then:
public void onTouch(View v, MotionEvent m){
if(beganOn!=null){
begaOn = v;
return;
} else {
// Where the view Tag, is an Integer to state what number it is in the sequence.
doSelectionOfViews(beganOn.getTag(),v.getTag());
begaOn = null;
}
}

override the onfling() method of the Gesture Detector. You will be able to get the Swipe direction Under this. Now take two counters for both direction and increment it(i.e count++) in the Right/left swipe and vice versa. Below I am posting the code by which you will be able to create that circular indicator. Whichever you want to make highlighted, You need to pass the index only.
public void updateIndicator(int currentPage) {
image_indicator.removeAllViews();
DotsScrollBar.createDotScrollBar(this, image_indicator, currentPage, 5);
}
Here image_indicator is an linear layout defined in xml.
public static class DotsScrollBar
{
LinearLayout main_image_holder;
public static void createDotScrollBar(Context context,
LinearLayout main_holder, int selectedPage, int count)
{
for (int i = 0; i < count; i++) {
ImageView dot = null;
dot = new ImageView(context);
LinearLayout.LayoutParams vp = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
vp.setMargins(8, 8, 8, 8);
dot.setLayoutParams(vp);
if (i == selectedPage) {
try
{
dot.setImageResource(R.drawable.page_hint_pre);
}
catch (Exception e)
{
}
} else
{
dot.setImageResource(R.drawable.page_hint_def);
}
main_holder.addView(dot);
}
main_holder.invalidate();
}
}
Pass the index in the upDateIndicator() method to make that particular incator highlighted.

RecyclerView - animate change of grid layout manager columns

I want to animate the change of my RecyclerViews GridLayoutManager. I defaulty show a list of items in a grid with 3 columns and the user can select to show more or less columns.
I would like the views in the RecyclerView to move/scale to their new positions, but I have no idea how this could be done.
What I want in the end
allow to scale the grid via an expand/contract touch gesture => I know how to do that
animate the change of the LayoutManager
Does anyone know how I can animate the change of the LayoutManager?

The source of inspiration here would be the Google Photos app,the stock Sony Gallery app
There are basically 2 approaches you can go with:
You modify the spancount of the GridLayoutManager using setSpanCount(int)
You set a very high span count(~100) use the SpanSizeLookUp to change the per item spanSize on the fly.
I have used the Gist provided by Musenkishi,for this answer to provide an animator to animate the changes in grid layout changes
I have used this approach in a sample GitHub project implementing the same.
Caveats:
I have currently used the click listener to keep modifying the the span size look up.This could be changed to a ItemGestureListener to capture pinch zoom events and change accordingly.
You need to determine a way to choose a span count so that all the items in a row occupy the entire screen width (and hence you do not see any empty space)
You call notifyItemRangeChanged using a runnable post delayed since you cannot call the notifyChanged methods from within bindView/createView etc.
After changing the span size,you need to notifyItemRangeChanged with an appropriate range so that all the items currently displayed on the screen are shifted accordingly.I have used (code at the bottom)
This is not a complete solution but a 2 hour solution for the same.You can obviously improve on all the points mentioned :).
I hope to keep updating the sample since this kind of views have always fascinated me.
Do not view this as the final solution but just a particular way of achieving this approach. If you were to use a StaggerredLayoutManager instead,you could easily avoid blank spaces between items.
public int calculateRange() {
int start = ((GridLayoutManager) grv.getLayoutManager()).findFirstVisibleItemPosition();
int end = ((GridLayoutManager) grv.getLayoutManager()).findLastVisibleItemPosition();
if (start < 0)
start = 0;
if (end < 0)
end = getItemCount();
return end - start;
}

I deal with the same problem as you, and so far I have not found a good solution.
Simple change of columns number in GridLayoutManager seems weird so for now I use animation to fade out/in entire layout. Something like this:
private void animateRecyclerLayoutChange(final int layoutSpanCount) {
Animation fadeOut = new AlphaAnimation(1, 0);
fadeOut.setInterpolator(new DecelerateInterpolator());
fadeOut.setDuration(400);
fadeOut.setAnimationListener(new Animation.AnimationListener() {
#Override
public void onAnimationStart(Animation animation) {
}
#Override
public void onAnimationRepeat(Animation animation) {
}
#Override
public void onAnimationEnd(Animation animation) {
productsRecyclerLayoutManager.setSpanCount(layoutSpanCount);
productsRecyclerLayoutManager.requestLayout();
Animation fadeIn = new AlphaAnimation(0, 1);
fadeIn.setInterpolator(new AccelerateInterpolator());
fadeIn.setDuration(400);
productsRecycler.startAnimation(fadeIn);
}
});
productsRecycler.startAnimation(fadeOut);
}
If you combine fade out/in animation with scaling each visible item, It will be a decent animation for GridLayoutManager changes.

You can do this with "gesture detector"
see the sample tutorial here http://wiki.workassis.com/pinch-zoom-in-recycler-view/ In this tutorial we will fetch images from gallery and show them in a grid layout in recycler view. You will be able to change layout on pinch gesture. Following are the screen shots of different layouts.
mScaleGestureDetector = new ScaleGestureDetector(this, new ScaleGestureDetector.SimpleOnScaleGestureListener() {
#Override
public boolean onScale(ScaleGestureDetector detector) {
if (detector.getCurrentSpan() > 200 && detector.getTimeDelta() > 200) {
if (detector.getCurrentSpan() - detector.getPreviousSpan() < -1) {
if (mCurrentLayoutManager == mGridLayoutManager1) {
mCurrentLayoutManager = mGridLayoutManager2;
mRvPhotos.setLayoutManager(mGridLayoutManager2);
return true;
} else if (mCurrentLayoutManager == mGridLayoutManager2) {
mCurrentLayoutManager = mGridLayoutManager3;
mRvPhotos.setLayoutManager(mGridLayoutManager3);
return true;
}
} else if(detector.getCurrentSpan() - detector.getPreviousSpan() > 1) {
if (mCurrentLayoutManager == mGridLayoutManager3) {
mCurrentLayoutManager = mGridLayoutManager2;
mRvPhotos.setLayoutManager(mGridLayoutManager2);
return true;
} else if (mCurrentLayoutManager == mGridLayoutManager2) {
mCurrentLayoutManager = mGridLayoutManager1;
mRvPhotos.setLayoutManager(mGridLayoutManager1);
return true;
}
}
}
return false;
}
});