Can one undo the changes he made on View properties using animate() on it?
In particular, how to undo changes made using animate().yBy(x)?
Note that I tried using animate().yBy(-x) and it works most of the times, but there are times that for some reason animate().yBy(x) seem not to be completed correctly (especially when the fragment pauses and then resumed) so animate().yBy(-x) is over-moving the view.
I'm looking for a way to make the View reset its properties to the way they were before I changed them using animate().
xBy() and yBy() animations affect the translationX and translationY properties. You can get the current values of those properties via getTranslationX() and getTranslationY(). So, to undo the previous animations, multiply the current property values by -1 and animate those. Or if you are seeking a "smash cut" jump (no animation), just call setTranslationX(0) or setTranslationY(0).
By using interpolator we can inverse the animation:
public class InverAnim implements Interpolator {
#Override
public float getInterpolation(float paramFloat) {
return Math.abs(paramFloat -1f);
}
}
On your animation you can set, new interpolator:
myAnimation.setInterpolator(new InverAnim());
In my App I use several DecalSprites as a part of my scene. They all have transparency (PNG-textures). When I have them overlapping, some of those show black background instead of transparency. Those DecalSprites have different Z-coordinates. So they should look like one behind another.
Please note also the line on the border of a texture. This is also something that I'm struggling to remove.
Update 1: I use PerspectiveCamera in the scene. But all the decals are positioned to face the camera as in 2d mode. So this "black" background appears only in certain cases e.g. when camera goes right (and all those decals appear in the left of the scene). Also I use the CameraGroupStrategy
Solved! The reason was that CameraGroupStrategy when ordering Decals (from farthest to closest to camera) takes the "combined" vector distance between camera and the Decal. When my camera panned to left or to right the distance to the Z-farthest Decal became LESS than the Z-closer Decal. This produced the artifact. Fix:
GroupStrategy strategy = new CameraGroupStrategy(cam , new ZStrategyComparator());
And the Comparator:
private class ZStrategyComparator implements Comparator<Decal> {
#Override
public int compare (Decal o1, Decal o2) {
float dist1 = cam.position.dst(0, 0, o1.getPosition().z);
float dist2 = cam.position.dst(0, 0, o2.getPosition().z);
return (int)Math.signum(dist2 - dist1);
}
}
Thanks to all guys who tried to help. Especially Xoppa. He sent me into the right direction in libGDX IRC.
I have a ViewPager which I need to move as a whole on button press. I use an animation for this.
When I press it, I translate the 'x' for it. I use setFillAfter(true) to keep the new position.
But when I change the page of the ViewPager, it jumps back to the original x-position!
I only saw this issue on Android 4.1, with Android 4.0 there is no problem! So it looks like some kind of regression in Android.
I attached a testproject where I could reproduce the issue without all my other stuff around it. I think it is best if you want to help me figure this out to import the project in your Eclipse and see it for yourself.
I also added to video's, one on my HTC One X where I see the issue, and the other on a tablet with Android 4.0, where the issue is not there.
I have been desperately looking to fix this ugly side effect, but no luck till now...
(Sorry for the big movie files...)
Video of Android 4.0 without the side effect
Video Android 4.1 with the side effect
the project where you can reproduce the issue with
Edit:
I added the following:
#Override
public void onAnimationEnd(Animation animation) {
RelativeLayout.LayoutParams lp = (android.widget.RelativeLayout.LayoutParams) myViewPager.getLayoutParams();
if (!i)
lp.setMargins(300,0,0,0);
else
lp.setMargins(0,0,0,0);
myViewPager.setLayoutParams(lp);
}
After that it stays at the correct position, but it 'flickers' quickly, like the animation is still showing at the end and when I change the margin, it still shows the offset it had after animation. Then it jumps to the correct position.
The main problem seems to be incorrect choice of animation type. You see, View Animation as a tool is not intended to be used with complex interactive objects like ViewPager. It offers only low-cost animation of the drawing place of views. The visual behaivior of the animated ViewPager in response to user-actions is undefined and should not be relied on.
Ugly flicks, when you substitute a "gost" with the real object are only natural.
The mechanism, that is intended to use in your case since API 11 is specialized property animator built in Views for optimized performance: ViewPropertyAnimator, or not specialized, but more versatile ObjectAnimator and AnimatorSet.
Property animation makes the View to really change its place and function normally there.
To make project, to use, say, ViewPropertyAnimator, change your listener setting to this:
btn.setOnClickListener(new OnClickListener() {
boolean b = false;
#Override
public void onClick(View v) {
if(b) {
myViewPager.animate().translationX(0f).setDuration(700);
}
else {
myViewPager.animate().translationX(300f).setDuration(700);
}
b=!b;
}
});
If you want to use xml configuration only, stick to |ObjectAnimator and AnimatorSet. Read through the above link for further information.
In case, you are anxious to support pre-Honeycomb devices, you can use Jake Warton's NineOldAndroids project. Hope that helps.
That's because the Animation's setFillAfter(true) doesn't actually change the position or any attributes of the View; all it does is create a Bitmap of the view's drawing cache and leaves it where the animation ends. Once the screen is invalidated again (ie. changing the page in the ViewPager), the bitmap will be removed and it will appear as if the View is returning to it's original position, when in fact it was already there.
If you want the View to retain it's position after the animation has finished, you need to actually adjust the View's LayoutParams to match your desired effect. To achieve this, you can override the onAnimationEnd method of the Animation, and adjust the LayoutParams of the View inside there.
Once you adjust the LayoutParams, you can remove your call to setFillAfter(true) and your View will actually stay where you expect it to.
Regarding the flicker issue:
I have encountered this issue before, and it stems from the possibility of the onAnimationEnd() call not syncing up with the next layout pass. Animation works by applying a transformation to a View, drawing it relative to its current position.
However, it is possible for a View to be rendered after you have moved it in your onAnimationEnd() method. In this case, the Animation's transformation is still being applied correctly, but the Animation thinks the View has not changed its original position, which means it will be drawn relative to its ENDING position instead of its STARTING position.
My solution was to create a custom subclass of Animation and add a method, changeYOffset(int change), which modifies the y translation that is applied during the Animation's applyTransformation method. I call this new method in my View's onLayout() method, and pass the new y-offset.
Here is some of my code from my Animation, MenuAnimation:
/**
* Signal to this animation that a layout pass has caused the View on which this animation is
* running to have its "top" coordinate changed.
*
* #param change
* the difference in pixels
*/
public void changeYOffset(int change) {
fromY -= change;
toY -= change;
}
#Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
float reverseTime = 1f - interpolatedTime;
float dy = (interpolatedTime * toY) + (reverseTime * fromY);
float alpha = (interpolatedTime * toAlpha) + (reverseTime * fromAlpha);
if (alpha > 1f) {
alpha = 1f;
}
else if (alpha < 0f) {
alpha = 0f;
}
t.setAlpha(alpha);
t.getMatrix().setTranslate(0f, dy);
}
And from the View class:
private int lastTop;
// ...
#Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
// the animation is expecting that its View will not be moved by the container
// during its time period. if this does happen, we need to inform it of the change.
Animation anim = getAnimation();
if (anim != null && anim instanceof MenuAnimation) {
MenuAnimation animation = (MenuAnimation) anim;
animation.changeYOffset(top - lastTop);
}
// ...
lastTop = top;
super.onLayout(changed, left, top, right, bottom);
}
Crucero has it right about setFillAfter not adjusting params post invalidation. When the view is re-layed out (which'll happen the pass after it's invalidated), its layout params will be the ones that always applied, so it should go back to the original position.
And Jschools is right about onAnimationEnd. Strongly encourage you to step through the source code with a debugger, where you'll instructively discover that an update is made that affects the drawn position of the view after onAnimationEnd is fired, at which point you've actually applied the layout params, hence the flicker caused by doubled up offset.
But this can be solved quite simply by making sure you relayout at the right time. You want to put your re-positioning logic at the end of the ui message queue at the time of animation end so that it is polled after the animation but before laying out. There's nowhere that suggests doing this, annoyingly, but I've yet find a reason in any release of the SDK reason why (when doing this just once and not incorrectly using ui thread) this shouldn't work.
Also clear the animation due to another issue we found on some older devices.
So, try:
#Override
public void onAnimationEnd(final Animation animation) {
myViewPager.post(new Runnable() {
#Override
public public void run() {
final RelativeLayout.LayoutParams lp = (android.widget.RelativeLayout.LayoutParams) myViewPager.getLayoutParams();
if (!someBooleanIPresume)
lp.setMargins(300,0,0,0);
else
lp.setMargins(0,0,0,0);
myViewPager.setLayoutParams(lp);
myViewPager.clearAnimation();
}
}
I know this has been asked before and I went through all the answers and nope this ain't that, and yes I have the activity named in the manifest so it's not that.
Here's my problem:
I have a sprite moving across the screen and when in the window where you choose the livewallpaper, I have a preference that lets the user choose the height (so they can move the sprite up or down) the only problem is the sprite is constantly moving so when they use the seekbar to move the sprite up or down I get the old 'Window already focused, ignoring focus gain of" Now if I go out and come back in again of course this stop and restarts it and the new preference hight is already in their so it moves to the new height then but not in the live preview.
Here is the sprite code:
private void addShipOne() {
int heightPosition = (screenSized / 2) - (screenSized / /*this.bigShipHeight*/gettheFreakingHeight());
int widthPosition = 0;
Point startPoint = new Point(widthPosition, heightPosition);
this._shipone.add(new SpaceShipOne(this._context, this, startPoint, 125));
(sorry about the method name I was using to test a quick version I was a bit frustrated at that point) lol
It then goes into an OnDraw method then into the render to render it all.
public void render(){
Canvas canvas = null;
try{
canvas = this._surfaceHolder.lockCanvas(null);
synchronized (this._surfaceHolder) {
this.onDraw(canvas);
}
}finally{
if(canvas != null){
this._surfaceHolder.unlockCanvasAndPost(canvas);
}
}
}
I have another preference that allows the user to choose the frequency of the ships appearing it works fine but it goes from left to right and changes ships then so it updates the frequency then, but the height one doesn't work, I tested the log to make sure the height int goes through and it does so its not that, the only thing I can come up with is the maybe add this when the ship turns left or right, but it does not work while its moving by the looks of it.
this.bigShipHeight is where the new height value goes into ( I was just testing it another way with the gettheFreakingHeight() (I used an if else statement for that method that used the frquency preference instead which does work nicely.
Just to add the full code part.
In the onDraw(Canvas canvas)
I render the _shipone as such
for (Renderable renderable : this._shipone) {
renderable.render(canvas);
}
Any help would be appreciated.
Thanks in advance
Sam
Ok I should of looked into the my sprite class first, sorry about this I answered my own question once again and it was too obvious, that's what I get for looking at the code way to long, I should walk away then come back it always is clearer then.
Just in case others run into this issue I'll put the answer.
In my sprite class which SpaceShipOne runs from I just added this
this.getSprite().setYPos(this._blimp.gettheFreakingHeight());
This updates right away with no window already focused.
I don't know why I didn't see this last night because it is the only place it can be added and be updated right away, all I had to do was set the Y position to the preference instead.
It works like a charm.
Hope this helps someone else out
Sam
I have a UI where the root layout is a RelativeLayout. It has a number of Views, such as fields, buttons, etc.
There are also two other panels that are initially invisible. When the user clicks a button, one of these panels slides in from the left, another slides in from the bottom. The problem is the frame rate is pathetic on a Nexus S.
I want to use setDrawingCacheEnabled(true) in order to (I hope) speed up the animation of these two panels. As a simplified example, here is roughly how I slide in one of these panels. I'll call it "detailPanel".
public class MyActivity extends Activity {
// Initially invisible.
private View detailPanel;
// A simple slide animation.
private Animation detailEnterAnimation;
...
public void someButtonClicked(View view) {
detailPanel.startAnimation(detailEnterAnimation);
detailPanel.setVisibility(View.VISIBLE);
detailPanel.setDrawingCacheEnabled(true);
}
}
Now in the DetailPanel I try to use the cache. I was hoping that bitmap rendering via the cache would improve performance:
public class DetailPanel extends LinearLayout {
public void draw(Canvas canvas) {
Bitmap cache = getDrawingCache();
if (cache != null) {
canvas.drawBitmap(cache, 0, 0, null);
} else {
super.draw(canvas);
}
}
}
The Bitmap is non-null and is the right size, but it is completely black.
Why is my bitmap black? That code may be obscenely wrong; I've tried a million different things and just cannot figure it out.
From Android documentation (http://developer.android.com/reference/android/view/View.html#setDrawingCacheEnabled%28boolean%29):
Enabling the drawing cache is similar to setting a layer when hardware acceleration is turned off. When hardware acceleration is turned on, enabling the drawing cache has no effect on rendering because the system uses a different mechanism for acceleration which ignores the flag. If you want to use a Bitmap for the view, even when hardware acceleration is enabled, see setLayerType(int, android.graphics.Paint) for information on how to enable software and hardware layers.
Maybe this is your case?
You may want to build your drawing cache before using it, otherwise It will give you a blank bitmap
public void someButtonClicked(View view) {
detailPanel.startAnimation(detailEnterAnimation);
detailPanel.setVisibility(View.VISIBLE);
detailPanel.setDrawingCacheEnabled(true);
detailPanel.buildDrawingCache(); //may be you need to add this?
}