Develop Reference

Animating a group of children in a viewgroup

I'm working on a custom ViewGroup.
This ViewGroup has a bunch of children. I need to animate a few and change their position. I understand that Android animations move just the bitmap and not the real object. I've been trying to MOVE them by following various resources but have failed.
What I'm doing with ViewGroup so far:
Measure children and the ViewGroup
Position children in onLayout
What I'm trying to do further
Use a custom animation to move a small subset of the children. I'm using a custom Animation object because I need to move a bunch of Views and I'm applying translationX on all of them together. The other option that I know is to start a separate Animation on all of them and the thought of which makes me think it's gonna be unoptimized.
Problem
Views animate fine, but their real position remains unchanged. So the next time I'm trying to do the same kind of animation, but on the new co-ordinates, it doesn't work. Because, their positions haven't updated.
What did I try
Use onAnimationEnd to layout each of the children to the new left, top, right and bottom position. All views vanished
On onAnimationEnd, reset translationX to zero and then start re-positioning the views. No effect of calling view.setTranslationX(0f)
Can someone please help me with the correct way of doing this? Thanks

when animating call layout() on your child Views

How to animate (move) a view above another view that becomes visible?

I'm using a RelativeLayout to stack a view A above a view B that is hidden (GONE). When the user clicks on view A, I want view A to slowly move upwards and then show view B (VISIBLE).
How can I accomplish this? Thanks!

Have a look at Android Animators. You can also google for something like "android animator position", you'll find tons of examples like this or this one.

For animating A you can use Animation class (and its subclasses) or Animator classes (such as ObjectAnimator, which animates a property of the view)
http://developer.android.com/reference/android/view/animation/TranslateAnimation.html
http://developer.android.com/reference/android/animation/ObjectAnimator.html

Android Animation - Button stays clickable

I am making a game in which I have 5 buttons, looking like clouds, falling from the "sky".
That means that when my activity starts, 'clouds' cannot be seen, since the marginTop is set to -100dp.
From that position they start falling down untill they get lost on the bottom side of the screen.
The thing is, I need those buttons to be clickable, during the process of animation.
So far, I found some documentation about how I can make the buttons clickable AFTER the animation ends. But I don't need that. I need to be able to click on the buttons through the animation time itself.
NOTE: I need something that works with versions before 3.0.
Anybody has any link to documentation or some example or anything ?

After doing some research, I found out that there are two types of animations:
View Animation and Property Animation.
The view animation can only animate View objects. It also lack a variety of animations, since it can do only stuff as scale, rotate, move... It cannot change background color, for example.
Also, the disadvantage of the View Animation is that it only change the position of where the View object is DRAWN. Physically, it still stays in the same position.
That's why the button is un-clickable, after the View Animation is finished upon it.
Property Animation, in the other hand, can animate both View and non-View objects and it doesn't have constraints as the View Animation.
When objects are moved, for example, with the property animation, they are not just drawn on some other position on the screen, but they are actually MOVED there.
Now, Property Animation is a lot more complex to write than the View Animation, so if you don't really need all the advantages of the Property Animation, it is suggested to use View Animation.
Source:
Property vs View Animation
Tutorial and SupportLybrary up to API 1:
nineoldandroids

You can change the buttons to imageViews and then do
imageView.setOnClickListener(myListener)
then set myListener to do whatever you previously wanted to happen on the buttons onClick. Your activity will have to implement OnClickListener
Added bonus: you can make the images look like clouds :)

Move view itself to animation's end position

I'm having a real serious problem.
I want to implement UI where some view is moving on the screen and the user can touch it.
I know that regular API-1 Animation framework move just the graphics of the view, and API-11 Animator framework move the view itself, but the problem is that it support only API-11+ which is very high.
I thought that instead of putting click listener on the view itself - I will identify which item was clicked by getting its position.
So this is what I will do:
* User touch the screen.
* Stop all the animations.
* Get all the animated views to the position where the animation was ended. (This is were I need your help).
* Iterate over the views and find out if the click was in the area of one of them.
But I can't find a way to move the view to the animation's end position.
If someone knows a way, I will be very thankful!
Thanks in advance,
Elad

But I can't find a way to move the view to the animation's end position.
Modify its LayoutParams to move it to the end position. Use getLayoutParams() on the View, cast it to the appropriate type based on its container, modify the LayoutParams object, then call setLayoutParams() on the View to commit the changes.

Struggling with view animations

I've got an absolute layout. In that layout is a custom view that takes up the left 3rd of the screen. I put a button in the layout that I want to cause the custom view to slide on and off of the screen. I've tried using animation resources (translates... "slidein" and "slideout") and the function startAnimation on the custom view, but I can't get the behavior I am looking for.
OK... I start with the custom view visible and in onCreate I find the view and animate it off screen using my slideout animation. That works fine. I figured out that I need to set "fillAfter" in the animation so that the custom view stays off screen.
Now, when I press my button I want to cause the custom view to slide back on the screen, so I trigger my slidein animation using startAnimation again but with slidein. BUT... that causes the view to first jump back to its original position AND THEN slide to the right... causing it to finish in the middle of the screen.
How do I get the animation to use the view's current position as the animation starting position, not its original position?
Thanks

I also experienced the flicker described in this question. My solution was to use the improved Honeycomb animation APIs. There is a convenient library that ports these all the way back to Android 1.0:
http://nineoldandroids.com/
For more on Honeycomb Animation APIs see:
http://android-developers.blogspot.com/2011/02/animation-in-honeycomb.html
In my case I had 2 overlapped LinearLayouts inside a RelativeLayout. I wanted to slide the top LinearLayout off the screen and reveal the bottom LinearLayout below. Then I wanted to slide to top LinearLayout back on screen to its original position so the top layout covered the bottom layout again. Using the old animation APIs I was seeing a flicker before the second animation (offscreen -> onscreen) was starting.
With the new APIs this task turned out to be trivial:
// Slide out (add to button handler)
ObjectAnimator.ofFloat(mTopLayout, "translationY", mTopLayout.getHeight()).start();
// Slide back in (add to button handler)
ObjectAnimator.ofFloat(mTopLayout, "translationY", 0).start();
The Honeycomb Animation APIs actually move objects around on the screen (rather than pretending to move them like the older animation APIs), so there is no need to fool around with filleAfter, fillBefore, etc.

Look into setting the fillAfter property to keep the end animation state