Develop Reference

Change object position dynamically using objectAnimator

I am trying out something and my aim is to move a button to a specific point on the screen. I have calculated the y-coordinate of the new position, then moveOn is called to update the position of the button.
The problem I have is that, after every call, button first returns to its initial position before moving. Please help a newbie.
public void moveOn() {
ObjectAnimator animation = ObjectAnimator.ofFloat(button, "translationY", translation_value);
}

Android View with a translate animation - positioning is not working as expected

I have a View that has an OnClickListener. When clicked, the view translates up to a certain position on the page. This is no problem, the view goes where it should. When the view is clicked again, I would like to position it somewhere else, but this is not the case. After a little bit of trouble shooting, I found that my View's getTop() method returns the same value - even after the translation animation has moved the view to a different part of the screen. For the second animation, it is not using the current position (as I would expect), it instead uses the initial position.
Few things that I am doing: I am using the ObjectAnimation class rather than the TranslationAnimation class, since I wanted to keep the OnClickListener functioning. With the TranslationAnimation class, I found that the view was correctly moved, but the OnClickListener was only working in the area that the View started from. Using the ObjectAnimation class, I was able to easily get the translation to work AND the OnClickListener functions correctly - it is triggered where the view currently is on the screen.
Here's what I have so far:
final LinearLayout child = layouts.get(i); //ArrayList containing some dynamic layouts
final int offset = target - child.getTop();
ObjectAnimator anim = ObjectAnimator.ofFloat(child,"translationY",offset);
anim.setDuration(250);
anim.start();
This is what happens when the view is clicked the first time. It translates up along the Y axis, where the offset determines how far the View needs to move from its current position.
Now, here's what happens on the second click. The goal here was to align the view with the parent's base.
target = parent.getBottom();
offset = target - child.getTop();
anim = ObjectAnimator.ofFloat(child, "translationY",offset);
anim.setDuration(250);
anim.start();
prev = child;
This is where things fall apart - child.getTop() returns the Y coordinate of the view's ORIGINAL position. Not the current position. So after the animation, the view is placed well below the bottom of the parent. I read a different question which stated that I should use child.getY() instead, which is supposed to give me the translationY position plus the top position, but this didn't lead to any better results. I can't seem to get this to work just right. I'd simply like to move the view from its current position to the bottom of the screen, but this appears to be a hard thing to accomplish. Any help would be appreciated.
EDIT
I have added an animation listener:
ObjectAnimator anim = ObjectAnimator.ofFloat(child,"translationY",offset);
anim.setDuration(250);
anim.addListener(new ObjectAnimator.AnimatorListener(){
#Override
public void onAnimationStart(Animator animation) {
System.out.println("start: " + child.getTop() + " " + child.getY());
}
#Override
public void onAnimationEnd(Animator animation) {
System.out.println("end: " + child.getTop() + " " + child.getY() + " " + child.getTranslationY());
child.setTop((int)child.getY());
System.out.println(child.getTop());
}
#Override
public void onAnimationCancel(Animator animation) {}
#Override
public void onAnimationRepeat(Animator animation) {}
});
anim.start();
Here I am setting the listener to try to change where the Top of the view is located. Behaviour is again not working as expected. The view is actually sent up above the screen when I do this. Output of the System.out looks like this:
start: 2008 2008.0
end: 2008 478.0 -1530.0
478
So calling child.getTop() after the animation is complete and setting a new position returns a positive integer, but the view is not actually completely on screen. It is above the screen, partly visible. The height of the view itself is about 700px. I am still so confused as to why this is such a hard thing to accomplish.
EDIT 2
I have also tried setting layoutparams inside the onAnimationEnd method:
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams)child.getLayoutParams();
params.removeRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
params.addRule(RelativeLayout.ALIGN_PARENT_TOP, RelativeLayout.TRUE);
params.topMargin = (int)child.getY();
child.setLayoutParams(params);
Result: child.getTop() still returns the original position of 2008.

You can get the very bottom of the screen coordinates like this :
float bottomOfScreen = getResources().getDisplayMetrics().heightPixels;
but you probably want it minus the height of your LinearLayout or else your LinearLayout will be cut off by the bottom :
float bottomOfScreen = getResources().getDisplayMetrics().heightPixels
- child.getHeight();
// if you want a little more space to the bottom
// try something like - child.getHeight()*2;
Then use ViewPropertyAnimator to animate your LL like this :
child.animate()
.translationY(bottomOfScreen)
.setInterpolator(new AccelerateDecelerateInterpolator())
.setDuration(250);
The Interpolator is just to make the animation more realistic.
In the case that child.getHeight() returns 0 , your Linear Layout has not been finished setting up by the system, in that case you might want to do something like :
child.post(new Runnable() {
#Override
public void run() {
float bottomOfScreen = getResources().getDisplayMetrics().heightPixels
- child.getHeight()*2;
child.animate()
.translationY(bottomOfScreen)
.setInterpolator(new AccelerateDecelerateInterpolator())
.setDuration(250);
}
});
Remember that a duration of 250 milliseconds is very fast, and does usually not look cool translating stuff on the screen, so you might want to set it a little higher, but thats just a matter of taste.

How do I animate expansion of a ListView?

I'm looking to implement an animation that will slide open or expand a ListView in android. At the moment, I'm using a scale animation (shown below)
Animation slideDown = new ScaleAnimation(1.0f, 1.0f, 0.0f, 1.0f);
slideDown.setDuration(1000);
but this doesn't work for 2 reasons:
1) I want the first item to fade in, and then the list to drop down. If I do a fade in animation, the entire list shows up and then jumps back up to the top and scales down to full size
2) I'm not really looking to scale, I would like to just reveal the ListView by animating down the bottom (if that makes sense).
Is there a way that I can do a TranslateAnimation on just the bottom margin or something similar? I looked into the drawable Clip resource, but that didn't seem to fit my needs here (I'm not sure how to apply it to a ListView). And I'm using a normal ListView, not an ExpandableListView, because I just have one group of items.

So I started searching for different things and it turns out that animating the height was my solution. Essentially I start with a dummy object in the list (so that it has at least 1 row), then I animate it from the height of that row to the height of the full list. Below is the code for the runnable that I am now calling.
private Runnable slideDownList1 = new Runnable() {
#Override
public void run() {
final ListView detail = (ListView)getView().findViewById(R.id.detail_menu_1);
ValueAnimator va = ValueAnimator.ofInt(detail.getHeight(), detail.getHeight()*mItem.containedObjects.size());
va.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
public void onAnimationUpdate(ValueAnimator animation) {
Integer value = (Integer) animation.getAnimatedValue();
detail.getLayoutParams().height = value.intValue();
detail.requestLayout();
}
});
va.setDuration(1000);
va.start();
}
};
The XML is just a basic ListView with the id of detail_menu_1.

The new element Recycler View include animations. You can use it with Support Library
https://developer.android.com/training/material/lists-cards.html

Android: call requestLayout() after update v.layout parameter causes layout reverts back to it's original position

I have framelayout which contains two relative layouts, one is on top of the other. When user clicks a button, the one on the top move 80% off the screen to the right. Then one on the bottom becomes clickable. This is what it looks like.
FrameLayout
RelativeLayout (bottom) RelativeLayout (top)
FilterWidgets Open/close button, ListView
It's really easy to achieve on 3.0+ with the new animation api which is Property base Animation. For the pre 3.0, because animation is view based. So I end up manually modify the layout property on onAnimationEnd. The call requestLayout to make it permanent, but only to find out the layout reverts back to original position. Anybody know how to move layout permanently?
see my other post if you want to see the whole picture:
https://stackoverflow.com/questions/14541265/changecursor-cause-layout-container-of-the-listview-to-reposition
theTranslationX.addListener(new AnimatorListenerAdapter() {
#Override
public void onAnimationEnd(Animator nullPointer) {
v.clearAnimation();
int theL = isMenuOn() ? 0 : v.getLeft() + getFilterWidth();
int theR = isMenuOn() ? v.getWidth() : v.getLeft() + getFilterWidth() + v.getWidth();
int theHeight = v.getHeight();
int theT = 0;
v.layout(theL, theT, theR, theHeight);
v.requestLayout();
}
});

This is 9 months late but try using:
yourView.layout(left,top,right,bottom); //all parameters are type int
However I don't think this is permanent, the position of the view will still be reset when you call requestLayout(), but give it a try.

Buttons on an animated view respond to clicks even when off screen?

I have a LinearLayout, I'm applying a translation animation to it. I'm filling the animation before and after. Visually it works fine. The animation ends by translating the view off screen. But if I click an x,y coordinate on screen that happens to be where the view was at some point during its animation, a button on the view has its click listener fire.
The only solution I've found is to add an animation listener, and when the animation ends, mark the buttons on the (now out of view) layout to visibility=gone, enabled=false. This seems bizarre - the view is no longer on screen, but it's still responding to click events. Is this a known thing, I'm probably not setting the animation up correctly?
Thanks
----- Update --------
I refactored my animation a little. Instead of using animation.setFillAfter(true), I set the layout's visibility to GONE when the animation is complete. Now it doesn't register clicks when off-screen. Still interested to know if this is a known thing, as it'd be easier to simply not have to add an animation listener etc.

Translate Animations on lower level API( below honey comb) changes where the button is drawn, but not where the button physically exists within the container. So, you are on your own to handle this situation. For more information about this you can refer to this link. One way is to actually change the location of the button in the layout(not by animation). Here is how you can achieve this:
params = (LayoutParams) mBtn.getLayoutParams();
TranslateAnimation animation = new TranslateAnimation(0, 0, 0, 400);
animation.setDuration(2000);
animation.setAnimationListener(mAnimationListener);
mBtn.startAnimation(animation);
....
....
private AnimationListener mAnimationListener = new AnimationListener() {
#Override
public void onAnimationStart(Animation animation) {
}
#Override
public void onAnimationRepeat(Animation animation) {
}
#Override
public void onAnimationEnd(Animation animation) {
params.topMargin = params.topMargin + 400;
mButton.setLayoutParams(params);
}
};
Here by changing the layout params we are changing the physical position of the button.
In your case as view is going off the screen so you just need to change the visibility of the button(View.GONE) on animation end.