Develop Reference

Imageview not moving

Im trying to make an Imageview (a ball) move around the layout and bounce a number of times before stoping when a buttom is pressed. The probles is that although the logcat says its happening, i dont see it moving.
Here it is
public class BallPhisics {
int x =400;
int y = 0;
boolean bounceX = false;
boolean bounceY= false;
int counter =0;
ImageView object;
public BallPhisics(ImageView i){
object=i;
}
public void applyMovement() {
while (true) {
object.setLeft((int) object.getX()+x); //i know i shouldnt use pixels
Log.d("EVENT", "X moved"); Log.d("Ended",Integer.toString(object.getLeft()));
object.setBottom((int)(object.getY() + y));
Log.d("EVENT", "Y moved");
try {
Thread.sleep(1000);
Log.d("EVENT", "Time 1 used");
} catch(InterruptedException ex) {
Thread.currentThread().interrupt();
}
if (object.getX()<=50||(object.getRight()<=50)){
bounceX =true;
break;
}
if (object.getY()<=50||object.getTop()<=50){
bounceY=true;
break;
}
}
this.bouncing();
}
public void bouncing(){
Log.d("EVENT", "Bouncing!!");
if (bounceX&&bounceY){
x=-x;
y=-y;
}
else if (bounceX){
x=-x;
y=(int)(Math.random()*100- 50 +y);
}
else if (bounceY) {
x = (int) (Math.random() * 100 - 50 + x);
y = -y;
}
counter++;
if(counter==5){return;}
this.applyMovement();
}
And on mainActivity the onclick event.
public void StartBall (View view){
ImageView imageview=(ImageView) findViewById(R.id.imageView);
BallPhisics phisics = new BallPhisics(imageview);
Log.d("EVENT", Integer.toString(imageview.getLeft() )+" before");
phisics.applyMovement();
Log.d("EVENT",Integer.toString(imageview.getLeft())+" after" );
}
Sorry if it is a lot of reading. By the way does anyone knows the proper way of moving a view?
Thanks in advance

First of all to move a View it's probably not a good idea to use setLeft (int left) or setBottom (int bottom) because this method is meant to be called by the layout system and should not generally be called otherwise, according to the documentation.
To move a View dynamically you should take a look at LayoutParams or setX (float x) and setY (float Y), if you can limit your support to Honeycomb (API Level 11).
Regardless which one you use, you may find it difficult to achieve a smooth movement. Therefore I recommend you to use the view animation system to perform tweened animation of your ImageView.
Below you will find an example of a chain animation that moves an ImageView starting from left to right with an arbitrary y-coordinate. After each translation from one x-border to the next, the onAnimationEnd will be called and start an animation in the other direction.
public class MainActivity extends Activity {
//the ImageView you want to animate
private ImageView imageview;
private Animation mAnimation;
//The coordinates the view moved to in the last animation
private float lastX=0;
private float lastY=0;
private float secondlastY;
//Listener that implements a translate animation chain
AnimationListener animationListener=new AnimationListener() {
#Override
public void onAnimationEnd(Animation animation) {
float newY=(float)(Math.random()*0.75);
//this prevents that we move back to the position we came from
// to get a more natural bounce animation
while(newY<=secondlastY+0.15 && newY>=secondlastY-0.15){
newY=(float)(Math.random()*0.75);
}
if(lastX==0.75f){
//test if we are on the right border of the parent
mAnimation=newAnimation(lastX,lastY,0f,newY);
mAnimation.setAnimationListener(animationListener);
lastX=0f;
}else if(lastX==0.0f){
//test if we are on the left border of the parent
mAnimation=newAnimation(lastX,lastY,0.75f,newY);
mAnimation.setAnimationListener(animationListener);
lastX=0.75f;
}
secondlastY=lastY;
lastY=newY;
imageview.startAnimation(mAnimation);
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageview=(ImageView) findViewById(R.id.imageView);
//the coordinates the first animation should move to
lastY=(float)(Math.random()*0.75);
lastX=0.75f;
mAnimation=newAnimation(0f,0f,lastX,lastY);
mAnimation.setAnimationListener(animationListener);
imageview.startAnimation(mAnimation);
}
//Method that returns a new animation with given start and end coordinates
private Animation newAnimation(float startX, float startY, float endX, float endY){
Animation mAnimation = new TranslateAnimation(
TranslateAnimation.RELATIVE_TO_PARENT, startX,
TranslateAnimation.RELATIVE_TO_PARENT, endX,
TranslateAnimation.RELATIVE_TO_PARENT, startY,
TranslateAnimation.RELATIVE_TO_PARENT, endY );
mAnimation.setDuration(2500);
mAnimation.setRepeatCount(0);
mAnimation.setRepeatMode(Animation.REVERSE);
mAnimation.setFillAfter(true);
return mAnimation;
}
}
Note:
The translation animation is relative to the parents width and height. If you move the View all the way to x=1.0 or y=1.0 you will move parts of the view out of the parent layout. Because it's sufficient for this example I chose to set 0.75 to the max position in either direction. But you should probably set this dynamically in regards to the width and height of your ImageView and ParentLayout.

View disappear after animating out of Screen bounds

I'm implementing an Animation for one menu in my project.
The animation itself is ok, the menu enters and exit just as I wanted: Slide from left to right and right to left, however...
If the entire view is OUT of the screen, then it NEVER comes back egain! If, at least one pixel is still inside the screen, then it comes back normally.
I belive that Android is disposing the layout, and not caring about it after out of the screen bounds. I tried to place a setVisibility(VISIBLE) but it also didn't worked.
Here is the code:
public class ChwaziMenuAnimation extends Animation{
float posStart = 0;
float posTarget = 100;
int getCurrentPosition(){
RelativeLayout.LayoutParams rootParam =
(RelativeLayout.LayoutParams) rootView.getLayoutParams();
return rootParam.leftMargin;
}
public void setTarget(float target){
// Save current position
posStart = getCurrentPosition();
posTarget = target;
}
#Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
RelativeLayout.LayoutParams rootParam =
(RelativeLayout.LayoutParams) rootView.getLayoutParams();
// Calculate current position
rootParam.leftMargin = (int) ((posTarget - posStart) * interpolatedTime + posStart);
rootView.setLayoutParams(rootParam);
}
/*
* Since we will be animating the margin, the bounds will always change
*/
public boolean willChangeBounds() {
return true;
};
};
And how I initialize the animation:
public void appear(){
Log.i(TAG, "appear");
menuAnimation.setTarget(0);
menuAnimation.setDuration(750);
rootView.clearAnimation();
rootView.startAnimation(menuAnimation);
}
public void disapear(){
Log.i(TAG, "disapear");
menuAnimation.setTarget(-400);
menuAnimation.setDuration(750);
rootView.startAnimation(menuAnimation);
}

I encountered the same problem, my workaround so far is to extend the view bounds to at least one pixel on the displayable area, and make that part transparent. Ugly, but for me it seems to work.
To make it even more weird: the view did not disappear, when shifted out the right side of the screen, only when shifted out the left side of the screen. But that might be device dependent.

Creating a 3D flip animation in Android using XML

I have created a 3D flip of a view using this android tutorial
However, I have done it programmatically and I would like to do it all in xml, if possible. I am not talking about simply shrinking a view to the middle and then back out, but an actual 3D flip.
Is this possible via xml?

Here is the answer, though it only works with 3.0 and above.
1) Create a new resources folder called "animator".
2) Create a new .xml file which I will call "flipping". Use the following xml code:
<?xml version="1.0" encoding="utf-8"?>
<objectAnimator xmlns:android="http://schemas.android.com/apk/res/android"
android:valueFrom="0" android:valueTo="360" android:propertyName="rotationY" >
</objectAnimator>
No, the objectAnimator tags do not start with an uppercase "O".
3) Start the animation with the following code:
ObjectAnimator anim = (ObjectAnimator) AnimatorInflater.loadAnimator(mContext, R.animator.flipping);
anim.setTarget(A View Object reference goes here i.e. ImageView);
anim.setDuration(3000);
anim.start();
I got all this from here.

Since the answers to this question are fairly dated, here is a more modern solution relying on ValueAnimators.
This solution implements a true, visually appealing 3D-flip, because it not just flips the view, but also scales it while it is flipping (this is how Apple does it).
First we set up the ValueAnimator:
mFlipAnimator = ValueAnimator.ofFloat(0f, 1f);
mFlipAnimator.addUpdateListener(new FlipListener(frontView, backView));
And the corresponding update listener:
public class FlipListener implements ValueAnimator.AnimatorUpdateListener {
private final View mFrontView;
private final View mBackView;
private boolean mFlipped;
public FlipListener(final View front, final View back) {
this.mFrontView = front;
this.mBackView = back;
this.mBackView.setVisibility(View.GONE);
}
#Override
public void onAnimationUpdate(final ValueAnimator animation) {
final float value = animation.getAnimatedFraction();
final float scaleValue = 0.625f + (1.5f * (value - 0.5f) * (value - 0.5f));
if(value <= 0.5f){
this.mFrontView.setRotationY(180 * value);
this.mFrontView.setScaleX(scaleValue);
this.mFrontView.setScaleY(scaleValue);
if(mFlipped){
setStateFlipped(false);
}
} else {
this.mBackView.setRotationY(-180 * (1f- value));
this.mBackView.setScaleX(scaleValue);
this.mBackView.setScaleY(scaleValue);
if(!mFlipped){
setStateFlipped(true);
}
}
}
private void setStateFlipped(boolean flipped) {
mFlipped = flipped;
this.mFrontView.setVisibility(flipped ? View.GONE : View.VISIBLE);
this.mBackView.setVisibility(flipped ? View.VISIBLE : View.GONE);
}
}
That's it!
After this setup you can flip the views by calling
mFlipAnimator.start();
and reverse the flip by calling
mFlipAnimator.reverse();
If you want to check if the view is flipped, implement and call this function:
private boolean isFlipped() {
return mFlipAnimator.getAnimatedFraction() == 1;
}
You can also check if the view is currently flipping by implementing this method:
private boolean isFlipping() {
final float currentValue = mFlipAnimator.getAnimatedFraction();
return (currentValue < 1 && currentValue > 0);
}
You can combine the above functions to implement a nice function to toggle the flip, depending on if it is flipped or not:
private void toggleFlip() {
if(isFlipped()){
mFlipAnimator.reverse();
} else {
mFlipAnimator.start();
}
}
That's it! Simple and easy. Enjoy!

I have created a simple program for creating flip of view like :
In Activity you have to create this method, for adding flip_rotation in view.
private void applyRotation(View view)
{
final Flip3dAnimation rotation = new Flip3dAnimation(view);
rotation.applyPropertiesInRotation();
view.startAnimation(rotation);
}
for this, you have to copy main class used to provide flip_rotation.
import android.graphics.Camera;
import android.graphics.Matrix;
import android.util.Log;
import android.view.View;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.Animation;
import android.view.animation.Transformation;
public class Flip3dAnimation extends Animation {
private final float mFromDegrees;
private final float mToDegrees;
private final float mCenterX;
private final float mCenterY;
private Camera mCamera;
public Flip3dAnimation(View view) {
mFromDegrees = 0;
mToDegrees = 720;
mCenterX = view.getWidth() / 2.0f;
mCenterY = view.getHeight() / 2.0f;
}
#Override
public void initialize(int width, int height, int parentWidth,
int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
mCamera = new Camera();
}
public void applyPropertiesInRotation()
{
this.setDuration(2000);
this.setFillAfter(true);
this.setInterpolator(new AccelerateInterpolator());
}
#Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
final float fromDegrees = mFromDegrees;
float degrees = fromDegrees
+ ((mToDegrees - fromDegrees) * interpolatedTime);
final float centerX = mCenterX;
final float centerY = mCenterY;
final Camera camera = mCamera;
final Matrix matrix = t.getMatrix();
camera.save();
Log.e("Degree",""+degrees) ;
Log.e("centerX",""+centerX) ;
Log.e("centerY",""+centerY) ;
camera.rotateY(degrees);
camera.getMatrix(matrix);
camera.restore();
matrix.preTranslate(-centerX, -centerY);
matrix.postTranslate(centerX, centerY);
}
}

The tutorial or the link by om252345 don't produce believable 3D flips. A simple rotation on the y-axis isn't what's done in iOS. The zoom effect is also needed to create that nice flip feel. For that, take a look at this example.
There is also a video here.

One of the better solution to flip the image with out use of the resource animation , is as follow:-
ObjectAnimator animation = ObjectAnimator.ofFloat(YOUR_IMAGEVIEW, "rotationY", 0.0f, 360f); // HERE 360 IS THE ANGLE OF ROTATE, YOU CAN USE 90, 180 IN PLACE OF IT, ACCORDING TO YOURS REQUIREMENT
animation.setDuration(500); // HERE 500 IS THE DURATION OF THE ANIMATION, YOU CAN INCREASE OR DECREASE ACCORDING TO YOURS REQUIREMENT
animation.setInterpolator(new AccelerateDecelerateInterpolator());
animation.start();

The simplest way to do it is using ViewPropertyAnimator
mImageView.animate().rotationY(360f);
Using the fluent interface you can build more complex and exciting animation.
E.g. you can enable hardware acceleration just call withLayer() method(API 16). More here
If you want to figure out how to create 3d flick animation, please follow here and here
I implemended my own solution only for a research. It includes: cancelation, accelleration, support API >= 15 and is based on Property Animation.
The entire animation includes 4 parts, 2 for each side.
Every objectAnimator has a listener that defines current animation index and represents an image in the onAnimationStart and current play time value in the onAnimationCancel.
It looks like
mQuarterAnim1.addListener(new AnimatorListenerAdapter() {
#Override
public void onAnimationStart(Animator animation) {
mQuarterCurrentAnimStartIndex = QUARTER_ANIM_INDEX_1;
mImageView.setImageResource(mResIdFrontCard);
}
#Override
public void onAnimationCancel(Animator animation) {
mQuarterCurrentAnimPlayTime = ((ObjectAnimator) animation).getCurrentPlayTime();
}
});
For start set call
mAnimatorSet.play(mQuarterAnim1).before(mQuarterAnim2)
If AnimatorSet was canceled we can calculate delta and run the reverse animation relying on the current index animation and the current play time value.
long degreeDelta = mQuarterCurrentAnimPlayTime * QUARTER_ROTATE / QUARTER_ANIM_DURATION;
if (mQuarterCurrentAnimStartIndex == QUARTER_ANIM_INDEX_1) {
mQuarterAnim4.setFloatValues(degreeDelta, QUARTER_FROM_1);
mQuarterAnim4.setDuration(mQuarterCurrentAnimPlayTime);
mAnimatorSet.play(mQuarterAnim4);
}
A full code snippet you can find here

Just put the view which you're going to animate it in place of viewToFlip.
ObjectAnimator flip = ObjectAnimator.ofFloat(viewToFlip, "rotationY", 0f, 360f); // or rotationX
flip.setDuration(2000); // 2 seconds
flip.start();

Adding to A. Steenbergen's great answer. When flipping the same view (updating a TextView for example) I removed the View.Visibility change in the constructor in order to keep the transition smoother.
public FlipListener(final View front, final View back) {
this.mFrontView = front;
this.mBackView = back;
}

How to restore textview scrolling position after screen rotation?

In my Android Layout, I have a TextView. This TextView is displaying a rather large spannable text and it is able to scroll. Now when the phone is rotated, the View is destroyed and created and I have to setText() the TextView again, resetting the scroll position to the beginning.
I know I can use getScrolly() and scrollTo() to scroll to pixel positions, but due to the change in View widths, lines become longer and a line that was at pixel pos 400 might now be at 250. So this is not very helpful.
I need a way to find the first visible line in a TextView in onDestroy() and then a way to make the TextView scroll to this specific piece of text after the rotation.
Any ideas?

This is an old question, but I landed here when searching for a solution to the same problem, so here is what I came up with. I combined ideas from answers to these three questions:
Scroll TextView to text position
Dynamically Modifying Contextual/Long-Press Menu in EditText Based on Position of Long Press
ScrollView .scrollTo not working? Saving ScrollView position on rotation
I tried to extract only the relevant code from my app, so please forgive any errors. Also note that if you rotate to landscape and back, it may not end in the same position you started. For example, say "Peter" is the first visible word in portrait. When you rotate to landscape, "Peter" is the last word on its line, and the first is "Larry". When you rotate back, "Larry" will be visible.
private static float scrollSpot;
private ScrollView scrollView;
private TextView textView;
protected void onCreate(Bundle savedInstanceState) {
textView = new TextView(this);
textView.setText("Long text here...");
scrollView = new ScrollView(this);
scrollView.addView(textView);
// You may want to wrap this in an if statement that prevents it from
// running at certain times, such as the first time you launch the
// activity with a new intent.
scrollView.post(new Runnable() {
public void run() {
setScrollSpot(scrollSpot);
}
});
// more stuff here, including adding scrollView to your main layout
}
protected void onDestroy() {
scrollSpot = getScrollSpot();
}
/**
* #return an encoded float, where the integer portion is the offset of the
* first character of the first fully visible line, and the decimal
* portion is the percentage of a line that is visible above it.
*/
private float getScrollSpot() {
int y = scrollView.getScrollY();
Layout layout = textView.getLayout();
int topPadding = -layout.getTopPadding();
if (y <= topPadding) {
return (float) (topPadding - y) / textView.getLineHeight();
}
int line = layout.getLineForVertical(y - 1) + 1;
int offset = layout.getLineStart(line);
int above = layout.getLineTop(line) - y;
return offset + (float) above / textView.getLineHeight();
}
private void setScrollSpot(float spot) {
int offset = (int) spot;
int above = (int) ((spot - offset) * textView.getLineHeight());
Layout layout = textView.getLayout();
int line = layout.getLineForOffset(offset);
int y = (line == 0 ? -layout.getTopPadding() : layout.getLineTop(line))
- above;
scrollView.scrollTo(0, y);
}

TextView can save and restore its state for you. If you aren't able to use that, you can disable that and explicitly call the methods:
http://developer.android.com/reference/android/widget/TextView.SavedState.html
http://developer.android.com/reference/android/widget/TextView.html#onSaveInstanceState()
http://developer.android.com/reference/android/widget/TextView.html#onRestoreInstanceState(android.os.Parcelable)

The best answer, I got by searching.
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
final ScrollView scrollView = (ScrollView) findViewById(R.id.Trial_C_ScrollViewContainer);
outState.putFloatArray(ScrollViewContainerScrollPercentage,
new float[]{
(float) scrollView.getScrollX()/scrollView.getChildAt(0).getWidth(),
(float) scrollView.getScrollY()/scrollView.getChildAt(0).getHeight() });
}
#Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
final float[] scrollPercentage = savedInstanceState.getFloatArray(ScrollViewContainerScrollPercentage);
final ScrollView scrollView = (ScrollView) findViewById(R.id.Trial_C_ScrollViewContainer);
scrollView.post(new Runnable() {
public void run() {
scrollView.scrollTo(
Math.round(scrollPercentage[0]*scrollView.getChildAt(0).getWidth()),
Math.round(scrollPercentage[1]*scrollView.getChildAt(0).getHeight()));
}
});
}

Slide expand animation in android

I have a simple ListView listing results in android. Upon click of each item, I would like it to slide down expand and show the content. Is there an easy way to do this in android?
Any help will be appreciated.

Here is example from Udinic. It had listview item expand with animation and require API level only 4+
Basically you need a animation class
/**
* This animation class is animating the expanding and reducing the size of a view.
* The animation toggles between the Expand and Reduce, depending on the current state of the view
* #author Udinic
*
*/
public class ExpandAnimation extends Animation {
private View mAnimatedView;
private LayoutParams mViewLayoutParams;
private int mMarginStart, mMarginEnd;
private boolean mIsVisibleAfter = false;
private boolean mWasEndedAlready = false;
/**
* Initialize the animation
* #param view The layout we want to animate
* #param duration The duration of the animation, in ms
*/
public ExpandAnimation(View view, int duration) {
setDuration(duration);
mAnimatedView = view;
mViewLayoutParams = (LayoutParams) view.getLayoutParams();
// decide to show or hide the view
mIsVisibleAfter = (view.getVisibility() == View.VISIBLE);
mMarginStart = mViewLayoutParams.bottomMargin;
mMarginEnd = (mMarginStart == 0 ? (0- view.getHeight()) : 0);
view.setVisibility(View.VISIBLE);
}
#Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
super.applyTransformation(interpolatedTime, t);
if (interpolatedTime < 1.0f) {
// Calculating the new bottom margin, and setting it
mViewLayoutParams.bottomMargin = mMarginStart
+ (int) ((mMarginEnd - mMarginStart) * interpolatedTime);
// Invalidating the layout, making us seeing the changes we made
mAnimatedView.requestLayout();
// Making sure we didn't run the ending before (it happens!)
} else if (!mWasEndedAlready) {
mViewLayoutParams.bottomMargin = mMarginEnd;
mAnimatedView.requestLayout();
if (mIsVisibleAfter) {
mAnimatedView.setVisibility(View.GONE);
}
mWasEndedAlready = true;
}
}
}
And use this :
View toolbar = view.findViewById(R.id.toolbar);
// Creating the expand animation for the item
ExpandAnimation expandAni = new ExpandAnimation(toolbar, 500);
// Start the animation on the toolbar
toolbar.startAnimation(expandAni);
ExpandAnimationExample

check out this answer. more than that you have to use the tweed animation. check the ApiDemos/Animation2 Examples. and also see the anim folder in ApiDemos. it helps a lot to me. according to your question slide_top_to_bottom will help.

The simplest way is to use an ObjectAnimator
ObjectAnimator animation = ObjectAnimator.ofInt(yourTextView, "maxLines", 40);
animation.setDuration(200).start();
This will change maxLines from your TextView to 40, over 200 milliseconds.
Beware of using yourTextView.getLineCount() to determine how many lines to expand to, because it wont give an accurate figure until after a layout pass. I recommend you just hard code a maxLines value that's longer than you expect the text would ever be. You could also estimate it using yourTextView.length() divided by the lowest number of characters you'd ever expect per line.