Develop Reference

Can I reuse ValueAnimator?

I have the following code (Android project in Scala):
val animator = new ValueAnimator
animator.setFloatValues(0f, 100f)
animator.setDuration(20000L)
animator.addUpdateListener(this) // prints current value to console
animator.start
override def onTouch(v: View, event: MotionEvent) = {
animator.setFloatValues(100f, 0f)
animator.setCurrentPlayTime(0)
if (!animator.isRunning) animator.start
true
}
If I touch the screen while animator is running then it correctly starts working backwards (since I've swapped the values). But if I touch the screen after it is finished then nothing happens, it does not start over.
Question is can I reuse this animator somehow and make it work again for given values after it has been stopped?

You can reuse animator in the following way:
...
animator.end();
animator.setFloatValues(...);
animator.start();
...
You can also use animator.cancel() instead of animator.end() and pass the last value from the last animation to the new animation as a starting float. For instance, if the last animated value is 50, you can call animator.setFloatValues(50, 0f) so your animations will look connected.
Considering the accepted answer states it's impossible, I would like to mention that the described approach is used in Touch Circle app when users make tap with two fingers. BTW, it's a very nice effect when object trembles a little bit - use it as you wish, code exerpt is below:
void shapeTremble(long delay) {
if (null == animatorTremble) {
ValueAnimator animator = new ValueAnimator();
animator.setDuration(850).setInterpolator(new AccelerateDecelerateInterpolator());
animator.addUpdateListener(new AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
setCircleScale((Float) valueAnimator.getAnimatedValue(), true);
}
});
animatorTremble = animator;
} else {
animatorTremble.cancel();
}
animatorTremble.setFloatValues(circleScale, 0.85f, 1.05f, 0.95f, 1.025f, 1.0f);
animatorTremble.setStartDelay(delay);
animatorTremble.start();
}

You cannot reuse an animation.
You need to reset() and reinitialize an animation object by calling the initialize() method before using the same object again. This is similar to instantiating a new animation object.

How to execute TranslateAnimation sequentially without knowing how many translate you'll have to do (android)?

The question is simple but i tried to search a solution in other similar questions, and i couldn't.
I have a arraylist path containing objects of type Coordinata that is an object containing two float X and Y, that is a coordinate. In substance, it's a list of coordinate. I need my ImageView image to move on a map on my view doing several subsequential TranslateTrasformation between the coordinate contained in the list path.
This can be easily done in the case of a fixed number of translation, doing the first translate and attaching it a setAnimationListener which could catch the end of the first animation and start in that moment the second and so on. I tried to iterate the process on my list path, using a while cycle, for i cannot really know how many coordinate will be in the path when the animation will start.
The result is the animation go on for the first couple of coordinates and then jump executing the animation for the last two coordinate in the path, ignoring all that is among these.
What is going on? I'm messing up with objects?
List<Coordinata> path; // properly filled with coordinates
Coordinata coordTempStart;
Coordinata coordTempArrival;
ImageView image;
ListIterator<Coordinata> pathIterator = path.listIterator();
if(pathIterator.hasNext()){
coordTempStart = (Coordinata) pathIterator.next();
}
if(pathIterator.hasNext()){
coordTempArrival = (Coordinata) pathIterator.next();
animation = new TranslateAnimation(coordTempStart.getX(),
coordTempArrival.getX(),
coordTempStart.getY(),
coordTempArrival.getY());
animation.setDuration(3000);
image.startAnimation(animation);
}
while(pathIterator.hasNext()){
coordTempStart=coordTempArrival;
coordTempArrival = (Coordinata) pathIterator.next();
animation.setAnimationListener(new TranslateAnimation.AnimationListener(){
public void onAnimationStart(Animation arg0) {}
public void onAnimationRepeat(Animation arg0) {}
public void onAnimationEnd(Animation arg0) {
animation = new TranslateAnimation(coordTempStart.getX(),
coordTempArrival.getX(),
coordTempStart.getY(),
coordTempArrival.getY());
animation.setDuration(3000);
image.startAnimation(animation);
}
});
}

I suggest to use ObjectAnimator and AnimatorSet to animate views. Object animator is available only for api > 11 but you can use NineOldAndroid if you have to keep the compatibility.
your code will be something like this (in pseudocode):
...
AnimatorSet animatorSet = new AnimatorSet();
while(pathIterator.hasNext()){
...
//Set _your_delta_x_ and _your_delta_y_ from iterator
...
ObjectAnimator xTrasnlationObjectAnimator = ObjectAnimator.ofFloat(v, view_x, _your_delta_x_);
ObjectAnimator yTrasnlationObjectAnimator = ObjectAnimator.ofFloat(v, view_y, _your_delta_y_);
animatorSet.playSequentially(xTrasnlationObjectAnimator, yTrasnlationObjectAnimator);
}
...
animatorSet.start()
to set right parameters to object animator refer the official documentation http://developer.android.com/reference/android/animation/ObjectAnimator.html

Just for the sake of completeness, i publish the actual code used to solve the problem:
// in this list you can insert as many animations you want
List<Animator> animations = new ArrayList<Animator>();
AnimatorSet animatorSet = new AnimatorSet();
ObjectAnimator xTrasnlationObjectAnimator = ObjectAnimator.ofFloat(image, View.TRANSLATION_X, (float)300);
xTrasnlationObjectAnimator.setRepeatCount(0);
ObjectAnimator yTrasnlationObjectAnimator = ObjectAnimator.ofFloat(image, View.TRANSLATION_Y, (float)300);
yTrasnlationObjectAnimator.setRepeatCount(0);
ObjectAnimator x2TrasnlationObjectAnimator = ObjectAnimator.ofFloat(image, View.TRANSLATION_X, (float)400);
x2TrasnlationObjectAnimator.setRepeatCount(0);
animations.add(xTrasnlationObjectAnimator);
animations.add(yTrasnlationObjectAnimator);
animations.add(x2TrasnlationObjectAnimator);
animatorSet.playSequentially(animations);
animatorSet.start();

android objectanimator expand/collapse from top to bottom animation?

I've been trying different approaches to get the expand/collapse animation with object animator but none of them so far worked.
I have used this solution and it works, but when I read the documentation it says it's more preferred to use animator to permanently animate objects rather than animation.
Problem with my code is that it always starts from top of the view, and yet I need to expand/collapse the view from bottom.
here is my code:
public boolean collapse( View view, int start, int end )
{
AnimatorSet set = new AnimatorSet();
ObjectAnimator a = ObjectAnimator.ofFloat( view, "translationY", start, end );
set.play( a );
set.setDuration( 3000L );
set.setInterpolator( new LinearInterpolator() );
set.addListener( new AnimatorListenerAdapter()
{
#Override
public void onAnimationEnd( Animator animation )
{
}
} );
set.start();
return true;
}

Trying using an ObjectAnimator.ofInt and use the property name of bottom. That will animate starting on the bottom of the view. TranslationY corresponds to the top of the view.

How to generate looping animation with ViewPropertyAnimator?

I want to build an animation of TextViews, which repeats itself just after completion.
For each View I want to animate, I use the following piece of code
final float oldX = v.getX();
final float newX = v.getX() - (float)totalWidth;
final AnimatorListenerAdapter listener = new AnimatorListenerAdapter() {
#Override
public void onAnimationEnd(Animator animation) {
v.setX(oldX);
animFinished = true;
//This line won't compile
//v.animate().setDuration(animDuration).setInterpolator(newsInterpolator)
// .setListener(listener).x(newX);
}
};
v.animate().setDuration(animDuration).setInterpolator(newsInterpolator)
.setListener(listener).x(newX);
I tried to place the last piece of code into the onAnimationEnd, but Java will not compile since it considers the object listener as not initialized. Moreover, I don't think that this "recursive" animation invocation is a good solution, it was the first thing which came to my mind. I am suspicious that there is a simple and sound way to implement looping property animation, but I failed to locate it, so I turned here for help.
Thanks in advance

Well, I am going to answer myself again.
TranslateAnimation class has methods about repeating the animation, so I used it instead of ViewPropertyAnimator.
The following code seems to work:
long duration = 1000* ((long)totalWidth / newsScrollSpeed);
System.out.println("totalWidth="+totalWidth);
TranslateAnimation anim = new TranslateAnimation(0,-totalWidth,0,0);
anim.setInterpolator(linearInterpolator);
anim.setDuration(duration);
anim.setRepeatCount(TranslateAnimation.INFINITE);
anim.setRepeatMode(TranslateAnimation.RESTART);
for(i=0;i<this.getChildCount();i++)
{
View v = this.getChildAt(i);
if(v.getId() == R.id.yuruyen_yazi)
{
continue;
}
v.startAnimation(anim);
}

Not elegant way, but it works:
Runnable runnable = new Runnable() {
#Override
public void run() {
// update newX
v.animate().setDuration(animDuration).setInterpolator(newsInterpolator).x(newX).withEndAction(this).start();
}
};
v.animate().setDuration(animDuration).setInterpolator(newsInterpolator).x(newX).withEndAction(runnable).start();

How to stop an animation (cancel() does not work)

I need to stop a running translate animation. The .cancel() method of Animation has no effect; the animation goes until the end anyway.
How do you cancel a running animation?

Call clearAnimation() on whichever View you called startAnimation().

On Android 4.4.4, it seems the only way I could stop an alpha fading animation on a View was calling View.animate().cancel() (i.e., calling .cancel() on the View's ViewPropertyAnimator).
Here's the code I'm using for compatibility before and after ICS:
public void stopAnimation(View v) {
v.clearAnimation();
if (canCancelAnimation()) {
v.animate().cancel();
}
}
... with the method:
/**
* Returns true if the API level supports canceling existing animations via the
* ViewPropertyAnimator, and false if it does not
* #return true if the API level supports canceling existing animations via the
* ViewPropertyAnimator, and false if it does not
*/
public static boolean canCancelAnimation() {
return Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH;
}
Here's the animation that I'm stopping:
v.setAlpha(0f);
v.setVisibility(View.VISIBLE);
// Animate the content view to 100% opacity, and clear any animation listener set on the view.
v.animate()
.alpha(1f)
.setDuration(animationDuration)
.setListener(null);

If you are using the animation listener, set v.setAnimationListener(null). Use the following code with all options.
v.getAnimation().cancel();
v.clearAnimation();
animation.setAnimationListener(null);

You must use .clearAnimation(); method in UI thread:
runOnUiThread(new Runnable() {
#Override
public void run() {
v.clearAnimation();
}
});

What you can try to do is get the transformation Matrix from the animation before you stop it and inspect the Matrix contents to get the position values you are looking for.
Here are the api's you should look into
public boolean getTransformation (long currentTime, Transformation outTransformation)
public Matrix getMatrix ()
public void getValues (float[] values)
So for example (some pseudo code. I have not tested this):
Transformation outTransformation = new Transformation();
myAnimation.getTransformation(currentTime, outTransformation);
Matrix transformationMatrix = outTransformation.getMatrix();
float[] matrixValues = new float[9];
transformationMatrix.getValues(matrixValues);
float transX = matrixValues[Matrix.MTRANS_X];
float transY = matrixValues[Matrix.MTRANS_Y];

Use the method setAnimation(null) to stop an animation, it exposed as public method in
View.java, it is the base class for all widgets, which are used to create interactive UI components (buttons, text fields, etc.).
/**
* Sets the next animation to play for this view.
* If you want the animation to play immediately, use
* {#link #startAnimation(android.view.animation.Animation)} instead.
* This method provides allows fine-grained
* control over the start time and invalidation, but you
* must make sure that 1) the animation has a start time set, and
* 2) the view's parent (which controls animations on its children)
* will be invalidated when the animation is supposed to
* start.
*
* #param animation The next animation, or null.
*/
public void setAnimation(Animation animation)

To stop animation you may set such objectAnimator that do nothing, e.g.
first when manual flipping there is animation left to right:
flipper.setInAnimation(leftIn);
flipper.setOutAnimation(rightOut);
then when switching to auto flipping there's no animation
flipper.setInAnimation(doNothing);
flipper.setOutAnimation(doNothing);
doNothing = ObjectAnimator.ofFloat(flipper, "x", 0f, 0f).setDuration(flipperSwipingDuration);

First of all, remove all the listeners which are related to the animatior or animator set. Then cancel the animator or animator set.
inwardAnimationSet.removeAllListeners()
inwardAnimationSet.cancel()

use this way:
// start animation
TranslateAnimation anim = new TranslateAnimation( 0, 100 , 0, 100);
anim.setDuration(1000);
anim.setFillAfter( true );
view.startAnimation(anim);
// end animation or cancel that
view.getAnimation().cancel();
view.clearAnimation();
cancel()
Cancel the animation. Canceling an animation invokes the animation
listener, if set, to notify the end of the animation.
If you cancel an animation manually, you must call reset()
before starting the animation again.
clearAnimation()
Cancels any animations for this view.

After going through all the things nothing worked. As I applied multiple animations in my views.
So below is the code that worked for me.
To start the animation that fades in and fade out continuously
val mAnimationSet = AnimatorSet()
private fun performFadeAnimation() {
val fadeOut: ObjectAnimator = ObjectAnimator.ofFloat(clScanPage, "alpha", 1f, 0f)
fadeOut.duration = 1000
val fadeIn: ObjectAnimator = ObjectAnimator.ofFloat(clScanPage, "alpha", 0f, 1f)
fadeIn.duration = 1000
mAnimationSet.play(fadeIn).after(fadeOut)
mAnimationSet.addListener(animationListener)
mAnimationSet.start()
}
The animation listener that loops in continuously
private val animationListener=object : AnimatorListenerAdapter() {
override fun onAnimationEnd(animation: Animator?) {
super.onAnimationEnd(animation)
mAnimationSet.start()
}
}
To stop the animation that going on in a loop. I did the following.
private fun stopAnimation() {
mAnimationSet.removeAllListeners()
}

Since none of other answers mention it, you can easily stop an animation using ValueAnimator's cancel().
ValueAnimator is very powerful for making animations. Here is a sample code for creating a translation animation using ValueAnimator:
ValueAnimator valueAnimator = ValueAnimator.ofFloat(0f, 5f);
int mDuration = 5000; //in millis
valueAnimator.setDuration(mDuration);
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator animation) {
// Update your view's x or y coordinate
}
});
valueAnimator.start();
You then stop the animation by calling
valueAnimator.cancel()`