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.

Collapsing Toolbar Layout - full height Image and scrolled at start

I have got a layout quite similar to this one: http://antonioleiva.com/collapsing-toolbar-layout/ - a classic approach to the Collapsing Toolbar.
I would like to extend it with following feature:
The ImageView is full screen height and at activity starts it is automatically scrolled half of it height down. When activity starts and user will scroll down, it will behave the old way, but (at activity starts) when he scrolls up, he can scroll all the way up to make the image full screen height size.
What kid of steps I need to take to make it behave the way I imagined?

Here is the the general Idea.
Activity:
public void setupMovingBar(final Boolean full) {
final Display dWidth = getWindowManager().getDefaultDisplay();
appBarLayout.post(new Runnable() {
#Override
public void run() {
int heightPx = dWidth.getHeight();
if (!full) {
heightPx = dWidth.getHeight() - (dWidth.getHeight() * 1 / 3);
}
setAppBarOffset(heightPx);
}
});
}
private void setAppBarOffset(int offsetPx) {
CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams();
AppBarLayout.Behavior behavior = (AppBarLayout.Behavior) params.getBehavior();
behavior.onNestedPreScroll(clContent, appBarLayout, null, 0, offsetPx, new int[]{0, 0});
}

Programmatically add items to scrollview top, but should not scroll to top

I have scrollview with child LinearLayout . I am adding data programmaticaly to it. When i add some data to top of linearlayout it automatically scrolls to top element. But i want something like , user reaches top -> scrolls upside to load previous data ->add data to linearlayout top but should not get focus, after addition complete , if user scrolls then and then only it should display .
How to achieve this?

Well I thought of a way and it works almost perfectly.
I have a LinearLayout (llCommunicationsLayout) inside a ScrollView (svCommunications) .
I inflate a new LinearLayout, I'm going to add views to the top of this new LinearLayout and then add this new layout to the LinearLayout inside the ScrollView.
This is the new layout:
final LinearLayout wrapperLayout = (LinearLayout) mInflater.inflate(R.layout.empty_layout, null);
I add my views to the 0'th position of this layout.
wrapperLayout.addView(view, 0);
After all the views are added into the wrapperLayout, I add the wrapperLayout into the llCommunicationsLayout (the one inside my ScrollView)
llCommunicationsLayout.addView(wrapperLayout, 0);
After this, I calculate their heights after the wrapperLayout is on screen (has a measurable height)
wrapperLayout.post(new Runnable() {
#Override
public void run() {
int wrapperHeight = wrapperLayout.getHeight();
int svHeight = svCommunications.getHeight();
int scrollHeight = Math.abs(svHeight - wrapperHeight);
DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
int displayHeight = displaymetrics.heightPixels / 4;
svCommunications.scrollTo(0, (scrollHeight + displayHeight));
}
});
Here, I get both the newly added layout's and the ScrollView's heights.
I calculate their difference, add the 1/4 of the height of the screen of my device and scroll it, voila!
It's not perfect, but after the layouts are added, it no longer scrolls to the top of the screen. Experiment with the displayHeight for different results.
Hope this helps someone out.

You can grab the current view which is on top of your LinearLayout then add new content to your LinearLayout and then scroll back to view which was previously on top. The code would be something like:
public void addViewsOnTop(List<View> views) {
final View currentViewOnTop = (linearLayout.getChildCount() > 0) ? linearLayout.getChildAt(0) : null;
// Add Views. Note that views will appear in reverse order
for(View view : views) {
linearLayout.addView(view, 0);
}
// Scroll back to view which was on top
if(currentViewOnTop != null) {
new Handler().post(new Runnable() {
#Override
public void run() {
scrollView.scrollTo(0, currentViewOnTop.getBottom());
}
});
}
}

Solved....
Try this, worked for me ,
lv_chat.setAdapter(adapter);
lv_chat.setSelection(somePreviousPosition);

Can I partially hide a layout?

As I've a master in MS Paint, I will just upload a picture selfdescripting what I'm trying to achieve.
I've searched, but I'm not really sure what do I've to search. I've found something called Animations. I managed to rotate, fade, etc an element from a View (with this great tutorial http://www.vogella.com/articles/AndroidAnimation/article.html)
But this is a bit limited for what I'm trying to achieve, and now, I'm stuck, because I don't know how is this really called in android development. Tried words like "scrollup layouts" but I didn't get any better results.
Can you give me some tips?
Thank you.
You can see a live example, with this app: https://play.google.com/store/apps/details?id=alexcrusher.just6weeks
Sincerely,
Sergi

Use something like this as your layout (Use Linear, Relative or other layout if you wish):
<LinearLayout
android:id="#+id/lty_parent">
<LinearLayout
android:id="#+id/lyt_first" />
<LinearLayout
android:id="#+id/lyt_second"/>
</LinearLayout>
And then in an onClick method on whatever you want to use to control it, set the Visibility between Visible and Gone.
public void buttonClickListener(){
((Button) findViewById(R.id.your_button))
.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
if (lyt_second.getVisibility() == View.GONE) {
lyt_second.setVisibility(View.VISIBILE);
}
else {
lyt_second.setVisibility(View.GONE);
}
});
Which is fine if you just want a simple appear/disappear with nothing fancy. Things get a little bit more complicated if you want to animate it, as you need to play around with negative margins in order to make it appear to grow and shrink, like so:
We use the same onClick method that we did before, but this time when we click it starts up a custom SlideAnimation for the hidden/visible view.
#Override
public void onClick(View v) {
SlideAnimation slideAnim = new SlideAnimation(lyt_second, time);
lyt_second.startAnimation(slideAnim);
}
The implementation of the SlideAnimation is based on a general Animation class, which we extend and then Override the transformation.
public SlideAnimation(View view, int duration) {
//Set the duration of the animation to the int we passed in
setDuration(duration);
//Set the view to be animated to the view we passed in
viewToBeAnimated = view;
//Get the Margin Parameters for the view so we can edit them
viewMarginParams = (MarginLayoutParams) view.getLayoutParams();
//If the view is VISIBLE, hide it after. If it's GONE, show it before we start.
hideAfter = (view.getVisibility() == View.VISIBLE);
//First off, start the margin at the bottom margin we've already set.
//You need your layout to have a negative margin for this to work correctly.
marginStart = viewMarginParams.bottomMargin;
//Decide if we're expanding or collapsing
if (marginStart == 0){
marginEnd = 0 - view.getHeight();
}
else {
marginEnd = 0;
}
//Make sure the view is visible for our animation
view.setVisibility(View.VISIBLE);
}
#Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
super.applyTransformation(interpolatedTime, t);
if (interpolatedTime < 1.0f) {
// Setting the new bottom margin to the start of the margin
// plus the inbetween bits
viewMarginParams.bottomMargin = marginStart
+ (int) ((marginEnd - marginStart) * interpolatedTime);
// Request the layout as it happens so we can see it redrawing
viewToBeAnimated.requestLayout();
// Make sure we have finished before we mess about with the rest of it
} else if (!alreadyFinished) {
viewMarginParams.bottomMargin = marginEnd;
viewToBeAnimated.requestLayout();
if (hideAfter) {
viewToBeAnimated.setVisibility(View.GONE);
}
alreadyFinished = true;
}
hideAfter = false;
}
}
EDIT: If anyone had used this code before and found that if you click on the button that starts the animation more than once before the animation was finished, it would mess up the animation from then on, causing it to always hide the view after the animation finished. I missed the reset of the hideAfter boolean near the bottom of the code, added it now.

you can do this manually by using setvisibility feature on the event onClick()
or
use this
dynamically adding two views one below other

Android Layout Animation won't work

I have a LinearLayout (LayoutContentView) which can contain one or two view (SubView1 and SubView2) (they are eitherTextView or ImageView).
This layout is in another LinearLayout (MyScreenLayout).
I want to make an animation on LayoutContentView so it can move and show just a part of it in MyScreenLayout.
Both of these layouts have setClipChildren(false); so it can let it's children draw outside it-self.
Depending on different parameters, I can change the size of the content, and the size of the content I will show.
Basically, I expend from top to bottom to show the two subviews and unexpend for bottom to top to show only the second subview. Before I expend, I increase the size of the LayoutContentView, so it can show the two subviews, and after I unexpend, I decrease the size of the LayoutContentView, so it can only show the second subview, and it let space on the screen for other elements.
Here is my method for expending and un-expending LayoutContentView :
mLayoutContentView.clearAnimation();
float yFrom = 0.0F;
float yTo = 0.0F;
float xFrom = 0.0F;
float xTo = 0.0F;
if (expend) { // if we expend
// I change the height of my LayoutContentView so it we can show it's two subviews
final android.view.ViewGroup.LayoutParams lp = mLayoutContentView.getLayoutParams();
lp.height = subView1H + subView2H;
setLayoutParams(lp);
invalidate();
// we start the animation so it shows only the second subview
yFrom = -subView1H;
// and we animate from top to bottom until it shows the two subviews
yTo = 0;
} else { // if we un-expend
// we animate from bottom to top starting by showing the two subviews
yFrom = 0;
// and progressively hiding the first subview and showing only the second subview
yTo = -subView1H;
}
Animation anim = new TranslateAnimation(xFrom, xTo, yFrom, yTo);
anim.setDuration(1000);
anim.setFillAfter(true);
anim.setFillEnabled(true);
anim.setAnimationListener(new AnimationListener() {
#Override
public void onAnimationStart(Animation animation) {
}
#Override
public void onAnimationRepeat(Animation animation) {
}
#Override
public void onAnimationEnd(Animation animation) {
if (!expend) {
// if we un expend at the end of the animation we can set the size of LayoutContentView to the size of the second subview again
final android.view.ViewGroup.LayoutParams lp = mLayoutContentView.getLayoutParams();
lp.height = subView2H;
mLayoutContentView.setLayoutParams(lp);
invalidate();
}
}
});
mLayoutContentView.startAnimation(anim);
The way I made my animation I need it to apply on LayoutContentView, the layout which contain two subview, and with startAnimation() it doesn't do the animation.
I tried to use a LayoutAnimationController, but instead of doing the animation on the LayoutContentView, it does it on each of its children...
I also tried to do the animation on each children myself, but I don't know why, the second subview isn't shown.
Each time I've tried to use HierarchyViewer, but it's does see the change made by the animation.
Does anyone know a solution or have faced the same problem and found a good solution ?
EDIT :
Well it seems that if you set a background color to your TextView and move them with animation, the background move but even if you have set the fill after parameter to your animation, the background moves back to it's original position or something like that, and therefore as I set a background color to both of my SubViews, somewhat one of the SubView's background hide the background of the other...
And there also a problem if after the animation, one of the SubView is still outside the its layout, there is also a problem during the animation, so I add a limitation to what I intended to here too.