Develop Reference

Android: LinearLayout slide off screen animation

I have two layouts (green on top, red on bottom) in a vertical LinearLayout (parent) looking similar to this:
.
When focus goes from the green to red, I would like the green to slide up off the screen and have the red simultaneously slide up with it and fill the whole screen. And when focus moves from red back up I want the green to slide back into the screen and return to the original configuration. I have tried looking at many other questions but none have had the solution I need. I tried just changing visibility between gone and visible but I want it to be a smooth animation. I've tried using parentLayout.animate().translationY(greenLayout.getHeight()) on the outer LinearLayout and that does give the animation I want but then the red does not expand to fill the screen, like this:
.
I know this question is similar to this one but that question is really old and only had one answer which didn't work for me.

My solution has a lot of different pieces, so I'll start with the full XML and java code, and then talk about the important bits:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical">
<View
android:id="#+id/green"
android:layout_width="match_parent"
android:layout_height="100dp"
android:background="#0f0" />
<View
android:id="#+id/red"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#f00"/>
</LinearLayout>
In the XML, the only really important part is that the red view uses a height of 0dp and weight of 1. This means it takes up all extra vertical space, which will be important when we get rid of the green view.
public class MainActivity extends AppCompatActivity {
private int originalHeight;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final View green = findViewById(R.id.green);
final View red = findViewById(R.id.red);
green.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
green.getViewTreeObserver().removeGlobalOnLayoutListener(this);
originalHeight = green.getHeight();
}
});
green.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
animateHeightOfView(green, originalHeight, 0);
}
});
red.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
animateHeightOfView(green, 0, originalHeight);
}
});
}
private void animateHeightOfView(final View view, int start, int end) {
ValueAnimator animator = ValueAnimator.ofInt(start, end);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
int height = (int) valueAnimator.getAnimatedValue();
ViewGroup.LayoutParams params = view.getLayoutParams();
params.height = height;
view.setLayoutParams(params);
}
});
animator.start();
}
}
In the Java, the two main parts are the ViewTreeObserver.OnGlobalLayoutListener and the animateHeightOfView() method.
The OnGlobalLayoutListener exists to capture the green view's original height. We have to use a listener to do this instead of just writing originalHeight = green.getHeight() inside onCreate() because the green view isn't actually laid out at that point, so getHeight() would return 0 if we tried that.
The animateHeightOfView() method leverages the ValueAnimator class to animate the height of whatever view you pass to it. Since there's no direct setter for a view's height, we can't use simpler methods like .animate(). We set up the ValueAnimator to produce int values on every frame, and then we use a ValueAnimator.AnimatorUpdateListener to modify the view's LayoutParams to set the height.
Feel free to play with it. I'm using click listeners to trigger the animation, and you mentioned focus, but you should be able to call animateHeightOfView() in a different way if it suits you.

How to make bottom sheet (BottomSheetBehavior) expandable to arbitrary position?

I have bottom sheet, and I want to change its behavior so it would work like on the main screen of Google Maps application, where you can expand it to any position and leave it there and it won't automatically stick to the bottom or to the top. Here's my layout with bottom sheet:
<android.support.design.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.gms.maps.MapView
android:id="#+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<View
android:id="#+id/shadow"
android:layout_width="match_parent"
android:layout_height="16dp"
android:background="#drawable/shape_gradient_top_shadow"
app:layout_anchor="#+id/map_bottom_sheet" />
<LinearLayout
android:id="#+id/map_bottom_sheet"
android:layout_width="match_parent"
android:layout_height="300dp"
android:fillViewport="false"
android:orientation="vertical"
app:behavior_peekHeight="50dp"
android:background="#color/lightGray"
app:layout_behavior="android.support.design.widget.BottomSheetBehavior">
<include layout="#layout/bottom_sheet_top_buttons"/>
<android.support.v4.widget.NestedScrollView
android:id="#+id/bottom_sheet_content_fragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/lightGray"/>
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
What I need in essence is eliminate forcing of STATE_EXPANDED and STATE_COLLAPSED states when dragging is ended.
Here's a visual explanation of what I try to achieve:
As you can see, bottom sheet doesn't automatically anchor to the top or the bottom but stays at whatever position it was left.

Copy the code from android.support.design.widget.BottomSheetBehavior to make your own custom behavior. Then modify the onViewReleased() method which is responsible for the movement of the sheet after the drag ends. You also have to introduce a new state besides the existing ones - the state is helpful to restore the position and let others know in which state your sheet is at the moment with getState().
#Override
public void onViewReleased(View releasedChild, float xVel, float yVel) {
int top;
#State int targetState;
// Use the position where the drag ended as new top
top = releasedChild.getTop();
// You have to manage the states here, too (introduce a new one)
targetState = STATE_ANCHORED;
if (mViewDragHelper.settleCapturedViewAt(releasedChild.getLeft(), top)) {
setStateInternal(STATE_SETTLING);
ViewCompat.postOnAnimation(releasedChild, new SettleRunnable(releasedChild, targetState));
} else {
setStateInternal(targetState);
}
}

I have created a proof of concept originating from the orginal source code from the design library. You can view it here. The problem with the original behavior is it doesn't allow flings, and most methods are private so extending the class and overriding some methods in an attempt to achieve it won't get you very far either. My implementation allows for optional snapping behavior, transient states (don't automatically snap after drag) and customizations around setting peek height and max height.

Hi Alex you can try this code for similar expected behaviour, it is not as optimised but it will help you to understand the concept.
final DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
bottomSheetBehavior.setPeekHeight(200);
// set callback for changes
bottomSheetBehavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
#Override
public void onStateChanged(#NonNull View bottomSheet, int newState) {
Log.d(TAG, "onStateChanged: " + bottomSheet.getY() + "::" + bottomSheet.getMeasuredHeight() + " :: " + bottomSheet.getTop());
}
#Override
public void onSlide(#NonNull View bottomSheet, float slideOffset) {
ViewGroup.LayoutParams params = bottomSheet.getLayoutParams();
params.height = Math.max(0, metrics.heightPixels - (int) bottomSheet.getTop());
bottomSheet.setLayoutParams(params);
}
});

Change the weight of layout with an animation

In my main layout file, I have a RelativeLayout, with a weight of 1 (basically to display a map) above a LinearLayout with a weight of 2, declared this way :
<LinearLayout
android:id="#+id/GlobalLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<RelativeLayout
android:id="#+id/UpLayout"
android:layout_width="match_parent"
android:layout_height="0px"
android:layout_weight="1" >
</RelativeLayout>
<LinearLayout
android:id="#+id/DownLayout"
android:layout_width="match_parent"
android:layout_height="0px"
android:layout_weight="2"
android:orientation="vertical" >
</LinearLayout>
</LinearLayout>
DownLayout contains a list of items, when I click on an item, I would like to change the weight of DownLayout for 4, so the upper layout (the map) takes only 1/5 of the screen instead of 1/3.
I have managed to do it by changing the LayoutParams :
LinearLayout linearLayout = (LinearLayout) mActivity.findViewById(R.id.DownLayout);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT);
params.weight = 4.0f;
linearLayout.setLayoutParams(params);
It works but I'm not satisfied, the change is too immediate, there is no transition while I would like it to be smooth. Is there a way to use animation for that ?
I found some examples with ObjectAnimator to change the weightSum, but it does not do want I want (if I change only this property, I have some free space below my down layout) :
float ws = mLinearLayout.getWeightSum();
ObjectAnimator anim = ObjectAnimator.ofFloat(mLinearLayout, "weightSum", ws, 5.0f);
anim.setDuration(3000);
anim.addUpdateListener(this);
anim.start();
Is there a way to use ObjectAnimator (or something else) to do that ?
Thanks !

I recently came across a similar problem and solved it using a standard Animation (I have to target API 10 so couldn't use ObjectAnimator). I used a combination of the answer here with slight alterations to take into account weight instead of height.
My custom animation class looks as follows...
private class ExpandAnimation extends Animation {
private final float mStartWeight;
private final float mDeltaWeight;
public ExpandAnimation(float startWeight, float endWeight) {
mStartWeight = startWeight;
mDeltaWeight = endWeight - startWeight;
}
#Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) mContent.getLayoutParams();
lp.weight = (mStartWeight + (mDeltaWeight * interpolatedTime));
mContent.setLayoutParams(lp);
}
#Override
public boolean willChangeBounds() {
return true;
}
}
And its called by this method...
public void toggle() {
Animation a;
if (mExpanded) {
a = new ExpandAnimation(mExpandedWeight, mCollapsedWeight);
mListener.onCollapse(mContent);
} else {
a = new ExpandAnimation(mCollapsedWeight, mExpandedWeight);
mListener.onExpand(mContent);
}
a.setDuration(mAnimationDuration);
mContent.startAnimation(a);
mExpanded = !mExpanded;
}
Hopefully this will help you out, if you need more details or have questions about something let me know.

Correctly animating an Android ImageView (possibly using a Matrix)

So, I have a Layout that contains a Button and an ImageView. When you press the button the ImageView should slide out from the button like I just pulled down a rolldown curtain (bushing other views below it down). Basically what the image below show. When you press the button again the ImageView should, unlike the gif, smoothly animates up again.
.
Using this SO question I've managed to animate the height from 0 to full size but in the wrong direction. I set the scaleType to "Matrix" and the default behaviour when setting the height is to show the part from the top down to [height].
For the animation I'll need the opposite. So if I would set the height to 50dp it would show the bottom 50dp. Then I can move the ImageView down at the same time it's being revealed, thus giving the rolldown curtain effect.
I've looked throught all the different layout and view options and found nothing that seems to do this. So I'm guessing I need to specify the transformation matrix. I looked through the android.graphics.Matrix class but it's a little but too complicated for me. I simply have no idea how to use it.
If there is another, easier, way to do this then that would be fantastic but if not then I really need help with the matrix.
I'm also including the code here:
The Rolldown View XML
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/sliding_accordion"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:src="#drawable/acc_image"
android:contentDescription="#string/accord"
android:scaleType="matrix"
android:layout_below="#+id/acc_button"
android:layout_marginTop="-10dp"
android:layout_centerHorizontal="true"/>
<Button
android:id="#+id/acc_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
The implementation in code.
(Note, the MyCustomAnimation class is a copy-paste version of the class found here)
//Called from all constructors
private void create()
{
final Context context = getContext();
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
RelativeLayout layout = (RelativeLayout) inflater.inflate(R.layout.widget_accordion, this, false);
final Button theButton = (Button) layout.findViewById(R.id.topic_button);
final ImageView accordionView = (ImageView) layout.findViewById(R.id.sliding_accordion);
accordionView.setVisibility(INVISIBLE);
theButton.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
if (accordionView.getVisibility() == View.VISIBLE)
{
MyCustomAnimation a = new MyCustomAnimation(accordionView, 1000, MyCustomAnimation.COLLAPSE);
height = a.getHeight();
accordionView.startAnimation(a);
}
else
{
MyCustomAnimation a = new MyCustomAnimation(accordionView, 1000, MyCustomAnimation.EXPAND);
a.setHeight(height);
accordionView.startAnimation(a);
}
}
});
this.addView(layout);
}

This took a long time perfect. But I managed to do it after a lot of experimenting.
I animate the margins of the drawer but because of the unexpected behavior of negative margins the button that opens the drawer can not be positioned on top.
When the drawer is closed the XML looks like so:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/accordion"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<com.animationtest.drawer.Drawer
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/topic_drawer"
android:layout_centerHorizontal="true"
android:layout_marginTop="0dp"
android:visibility="invisible"/>
<com.animationtest.drawer.Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/topic_btn"
android:layout_marginTop="58dp"/>
</RelativeLayout>
Then when the button is pressed the top_margin of the drawer is increased until it has come to whatever position is needed (in this case drawerHeight - someOffset).
I used android.view.animation.Animation to animate the widget my applyTransformation function looks something like this (Note that mLayoutParams are the drawer params):
#Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
int valueDifference = Math.abs(startValue - endValue);
float valueChange = interpolatedTime * valueDifference;
if(currentState.equals(State.COLLAPSED)) {
// is closed and I want to open it
mLayoutParams.topMargin = Math.round(interpolatedTime * valueDifference);
}
else {
// is opened and I want to close it
mLayoutParams.topMargin = valueDifference - Math.round(interpolatedTime * valueDifference);
}
drawerView.requestLayout(); //this is my drawer
}
Finally, to hide the top of the drawer as it moves, I overrode my DrawerView's dispatchDraw method to looks like so:
#Override
protected void dispatchDraw(Canvas canvas) {
float height = getHeight();
float top = height - ((LayoutParams) getLayoutParams()).topMargin;
Path path = new Path();
RectF rectF = new RectF(0.0f, top, getWidth(), height);
path.addRoundRect(rectF, 0.0f, 0.0f, Path.Direction.CW);
canvas.clipPath(path);
super.dispatchDraw(canvas);
}
One final note:
Because of the Button's position one would need to set the widgets margin as a negative number for it to align correctly in a list or layout. In this case it would have to be -58dp.

How does one Animate Layout properties of ViewGroups?

I have the following layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent">
<FrameLayout android:id="#+id/viewgroup_left"
android:layout_height="match_parent"
android:layout_weight="2"
android:layout_width="0dp">
... children ...
</FrameLayout>
<LinearLayout android:id="#+id/viewgroup_right"
android:layout_height="match_parent"
android:layout_weight="1"
android:layout_width="0dp"
android:orientation="vertical">
... children ...
</LinearLayout>
</LinearLayout>
I end up with something like this:
+------------------------+------------+
| | |
| | |
| Left | Right |
| | |
| | |
+------------------------+------------+
When a certain toggle is toggled, I want to animate Left so that its width expands to fill the entire screen. At the same time, I would like to animate the width of Right so that it shrinks to zero. Later, when the toggle is toggled again, I need to restore things to the above state.
I've tried writing my own Animation that calls View.getWidth() but when I animate back to that value (by setting View.getLayoutParams().width) it is wider than when it began. I suspect I'm just doing it wrong. I have also read all the documentation on the Honeycomb animation stuff, but I don't want to translate or scale... I want to animate the layout width property. I can't find an example of this.
What is the correct way to do this?

Since noone helped you yet and my first answer was such a mess I'll try to give you the right answer this time ;-)
Actually I like the idea and I think this is a great visual effect which might be useful for a bunch of people. I would implement an overflow of the right view (I think the shrink looks strange since the text is expanding to the bottom).
But anyway, here's the code which works perfectly fine (you can even toggle while it's animating).
Quick explanation:
You call toggle with a boolean for your direction and this will start a handler animation call loop. This will increase or decrease the weights of both views based on the direction and the past time (for a smooth calculation and animation). The animation call loop will invoke itself as long it hasn't reached the start or end position.
The layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:weightSum="10"
android:id="#+id/slide_layout">
<TextView
android:layout_weight="7"
android:padding="10dip"
android:id="#+id/left"
android:layout_width="0dip"
android:layout_height="fill_parent"></TextView>
<TextView
android:layout_weight="3"
android:padding="10dip"
android:id="#+id/right"
android:layout_width="0dip"
android:layout_height="fill_parent"></TextView>
</LinearLayout>
The activity:
public class TestActivity extends Activity {
private static final int ANIMATION_DURATION = 1000;
private View mSlidingLayout;
private View mLeftView;
private View mRightView;
private boolean mAnimating = false;
private boolean mLeftExpand = true;
private float mLeftStartWeight;
private float mLayoutWeightSum;
private Handler mAnimationHandler = new Handler();
private long mAnimationTime;
private Runnable mAnimationStep = new Runnable() {
#Override
public void run() {
long currentTime = System.currentTimeMillis();
float animationStep = (currentTime - mAnimationTime) * 1f / ANIMATION_DURATION;
float weightOffset = animationStep * (mLayoutWeightSum - mLeftStartWeight);
LinearLayout.LayoutParams leftParams = (LinearLayout.LayoutParams)
mLeftView.getLayoutParams();
LinearLayout.LayoutParams rightParams = (LinearLayout.LayoutParams)
mRightView.getLayoutParams();
leftParams.weight += mLeftExpand ? weightOffset : -weightOffset;
rightParams.weight += mLeftExpand ? -weightOffset : weightOffset;
if (leftParams.weight >= mLayoutWeightSum) {
mAnimating = false;
leftParams.weight = mLayoutWeightSum;
rightParams.weight = 0;
} else if (leftParams.weight <= mLeftStartWeight) {
mAnimating = false;
leftParams.weight = mLeftStartWeight;
rightParams.weight = mLayoutWeightSum - mLeftStartWeight;
}
mSlidingLayout.requestLayout();
mAnimationTime = currentTime;
if (mAnimating) {
mAnimationHandler.postDelayed(mAnimationStep, 30);
}
}
};
private void toggleExpand(boolean expand) {
mLeftExpand = expand;
if (!mAnimating) {
mAnimating = true;
mAnimationTime = System.currentTimeMillis();
mAnimationHandler.postDelayed(mAnimationStep, 30);
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.slide_test);
mLeftView = findViewById(R.id.left);
mRightView = findViewById(R.id.right);
mSlidingLayout = findViewById(R.id.slide_layout);
mLeftStartWeight = ((LinearLayout.LayoutParams)
mLeftView.getLayoutParams()).weight;
mLayoutWeightSum = ((LinearLayout) mSlidingLayout).getWeightSum();
}
}

Just adding my 2 cents here to Knickedi's excellent answer - just in case someone needs it:
If you animate using weights you will end up with issues with clipping/non-clipping on contained views and viewgroups. This is especially true if you use viewgroups with weight as fragment containers. To overcome it, you might as well need to animate margins of the problematic child views and viewgroups / fragment containers.
And, to do all these things together, its always better to go for ObjectAnimator and AnimatorSet (if you can use them), along with some utility classes like MarginProxy

A different way to the solution posted by #knickedi is to use ObjectAnimator instead of Runnable. The idea is to use ObjectAnimator to adjust the weight of both left and right views. The views, however, need to be customised so that the weight can be exposed as a property for the ObjectAnimator to animate.
So first, define a customised view (using a LinearLayout as an example):
public class CustomLinearLayout extends LinearLayout {
public CustomLinearLayout(Context context) {
super(context);
}
public CustomLinearLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CustomLinearLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
public void setMyWeight(float value) {
LinearLayout.LayoutParams p = (LinearLayout.LayoutParams)getLayoutParams();
p.weight = value;
requestLayout();
}
}
Then, update the layout XML to use this custom linear layout.
Then, when you need to toggle the animation, use ObjectAnimator:
ObjectAnimator rightView = ObjectAnimator.ofFloat(viewgroup_right, "MyWeight", 0.5f, 1.0f);
ObjectAnimator leftView = ObjectAnimator.ofFloat(viewgroup_left, "MyWeight", 0.5f, 0.0f);
AnimatorSet animatorSet = new AnimatorSet();
animatorSet.setDuration(1000); // 1 second of animation
animatorSet.playTogether(rightView, leftView);
animatorSet.start();
The above code assumes both views are linear layout and are half in weight to start with. The animation will expand the right view to full weight (so the left one is hidden). Note that ObjectAnimator is animated using the "MyWeight" property of the customised linear layout. The AnimatorSet is used to tie both left and right ObjectAnimators together, so the animation looks smooth.
This approach reduces the need to write runnable code and the weight calculation inside it, but it needs a customised class to be defined.