Develop Reference

Why doesn't EditText get focus with setFillAfter(true)?

So when you have the visibility set to INVISIBLE on the EditText fields it doesn't want to get focus for the keyboard.
I fixed this issue by changing the visibility on those fields after the animation completes like this:
edit_text.setVisibility(View.INVISIBLE);
final Animation fadeInAnimation = AnimationUtils.loadAnimation(getActivity(), R.anim.fade_in_view);
fadeInAnimation.setFillAfter(true);
edit_text.startAnimation(fadeInAnimation);
edit_text.setVisibility(View.VISIBLE);
But I want to know why it doesn't get focus. Shouldn't setFillAfter(true) set them to visible again?

The description for setFillAfter(boolean fillAfter) says
If fillAfter is true, the
transformation that this animation
performed will persist when it is
finished.
When set to true it does do this
An animation on Android does not actually animate the View itself, it
animates a bitmap representation of the View
Check out: Animation.setFillAfter/Before - Do they work/What are they for?

Animated Views move outside of my layout

I have a ScrollView which contains several RelativeLayouts and LinearLayouts like this:
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/scroll"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true" >
<RelativeLayout >
</RelativeLayout>
<LinearLayout >
</LinearLayout>
</ScrollView>
Now, when I click on one of those layouts, I want it to expand and reveal more information. I have managed to do this by scaling the layout I want vertically with a PropertyAnimator:
relativeLayout.animate().scaleY(100).setDuration(duration).start();
At the same time, I use another PropertyAnimator to move any Views below the one I expanded vertically so that there's enough space for the expanded layout. So far it is working.
Unfortunately, the Views that move somehow end up outside of the viewport of the ScrollView, so I'm unable to scroll down and see the information in those Views. Essentially, the vertical translation of those views renders their lower part unreachable, since the viewport does not expand too.
I have set android:fillViewPort="true" on the ScrollView. And I have also tried to do it programmatically with setFillViewPort() but neither has had any effect.
What's wrong? Why is it not working?

When you perform translation animations on Views then those Views don't really move inside the layout. Its just visual for the User, but when it comes to layouting and/or measuring than any translation values are ignored. It is always as if the Views are not translated at all.
What I am guessing you are doing right now is this:
You react to the click event and expand the View you want to expand.
You calculate how much the other Views need to move to accommodate the expanded View.
Then you perform translate animations on those Views by much they need to move.
And then as a result suddenly a few Views move off screen.
This approach can actually never work. You always need to remember that a Views position in the layout is determined just by the layout. All your translations are essentially just for show. So this is what's actually happening when you try to do the above:
You react the to the click event and expand the View.
This expansion causes Android to start a layouting and measuring process. The positions and sizes of all Views is calculated and they are positioned at their new location with their new size.
Since now the Views are already at the location they are going to be after the expansion you translation animation just moves the Views further down, beyond the point they are supposed to be.
As a side effect of this the Views seem to move off screen for no apparent reason.
So what can you do about this? Essentially you need to tackle this problem the other way around. As I mentioned above Android already calculates the new sizes and positions of all Views for you, and you can use that to your advantage.
There are two basic solutions for your problem. Either you let Android perform the animations for you with LayoutTransitions or you perform your animations manually. Both ways use something called the ViewTreeObserver. It can be used to listen for changes in the layout or new drawing processes.
But first and foremost: ScrollView is supposed to work with only one child. So to prevent any future bugs or problems put all your items in the ScrollView inside of another LinearLayout with vertical orientation.
1) Using LayoutTransition
This would only work from API Level 16 and above. Below API Level 16 visibility animations and translation animations would be handled automatically, but to get height changes animated you need to have API level 16.
One important thing I have to mention is that:
LayoutTransition animates changes for you. So you can remove all you custom animations if you use it. If you leave your own animations in you are just going to create conflicts with the animations performed by LayoutTransition.
If you don't like the animations performed by LayoutTransition you can customise them! I will explain how to do that further down below.
I usually use a helper method like this to setup a LayoutTransition.
public static void animateLayoutChanges(ViewGroup container) {
final LayoutTransition transition = new LayoutTransition();
transition.setDuration(300);
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
transition.enableTransitionType(LayoutTransition.CHANGING);
transition.enableTransitionType(LayoutTransition.APPEARING);
transition.enableTransitionType(LayoutTransition.CHANGE_APPEARING);
transition.enableTransitionType(LayoutTransition.DISAPPEARING);
transition.enableTransitionType(LayoutTransition.CHANGE_DISAPPEARING);
}
container.setLayoutTransition(transition);
}
This will enable all possible automatic transitions on API Level 16 and above and just use the by default enabled transitions below that. Just use it like this:
AnimatorUtils.animateLayoutChanges(linearLayout);
If you call this method on the LinearLayout in your ScrollView then all changes to height/width/visibility of the LinearLayout and its direct children will be animated for you. Also item add/remove animations are taken care of for you.
To enable all kinds of transitions like resize animations you need to set the LayoutTransitions in code, but you can enable basic transitions like item add/remove animations by setting the property
android:animateLayoutChanges="true"
on a ViewGroup in your xml layout.
There exists only minimal documentation on LayoutTransitions, but the basics are covered here.
If you want you can customise the animations for each event like adding/removing a View or changing something about the View like this:
// APPEARING handles items being added to the ViewGroup
transition.setAnimator(LayoutTransition.APPEARING, someAnimator);
// CHANGING handles among other things height or width changes of items in the ViewGroup
transition.setAnimator(LayoutTransition.CHANGING, someOtherAnimator);
Here is a DevByte video which explains LayoutTransitions in greater detail:
LayoutTransitions enable easy fade/move/resize animations
Also note that container views can essentially cut off parts of the animations when the height of a parent changes. This won't happen in your case since your ScrollView has a fixed size and does not resize based on the children inside the ScrollView, but if you implement something like this in a ViewGroup with wrap_content then you need to set android:clipChildren="false" on all containers above the Views you are trying to animate. You can alternatively also use setClipChildren() in code.
2) Animating all items manually.
This is a much more difficult than using LayoutTransitions, mainly because you have to know a lot about the layouting and measuring process, otherwise you are going to cause problems. Nevertheless once you get the hang of it you can perform all kinds of custom animations.
The basic process is like this:
Record current View state.
Change layout to the state after the animations are finished
After Android is done layouting and measuring everything record the new values.
Now animate the Views from their old position to their new one
The core of this process is listening for changes in the view hierarchy. This is done using the ViewTreeObserver. There are multiple possible callbacks you can use, for example OnPreDrawListener or OnGlobalLayoutListener. Generally you would implement them like this:
final Animator animator = setupAnimator();
animator.setTarget(view);
// Record the current state
animator.setupStartValues();
modifyChildrenOfLinearLayout();
linearLayout.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
// Remove the callback immediately we only need to catch it this one time.
linearLayout.getViewTreeObserver().removeOnGlobalLayoutListener(this);
// Record the new state
animator.setupEndValues();
// Start the animation
animator.start();
}
});
OnGlobalLayoutListener is better at catching layout changes since it is called after a layouting process has finished. OnPreDrawListener is called before the next frame is drawn, but their is no guarantee that the layouting process has already finished. But in practice this difference is negligible. Much more important is that on older slower devices there might be a short flash of the layout in its new state because they need some time to process each step. You can prevent that by using an OnPreDrawListener and returning false once. Since OnGlobalLayoutListener is also only completely available on newer API levels you should in most cases use OnPreDrawListener.
If LayoutTransitions does not provide you with an adequate solution to your problem and you have/want to implement the animations manually than learning how to perform animations efficiently is important. You can look at the source code of LayoutTransition here. The implementation of LayoutTransition essentially does exactly what I have been explaining here and it is a best practice implementation. I often find myself looking through the source code of the android.animation package to learn new things about how to animate efficiently and if you want to understand animations on Android I suggest you do the same!
You can also watch a few Android DevBytes videos about animations like this one:
ListView Expanding Cells Animation
In this video he explains how to animate an expanding cell in ListView by using an OnPreDrawListener.
Just always remember, the Layouting Engine is your friend. Don't try to reinvent the wheel and do stuff manually a layouting process would already do for you. And never call requestLayout() while performing animations!

From Android Developer site :
A ScrollView is a FrameLayout, meaning you should place one child in it containing the entire contents to scroll; this child may itself be a layout manager with a complex hierarchy of objects. A child that is often used is a LinearLayout in a vertical orientation, presenting a vertical array of top-level items that the user can scroll through.
I can see that you have added multiple layouts as child in Scroll View, please add one linear layout and add rest of layout in that LinearLayout.
Hope it will solve your problem

Try this.
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/scroll"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<RelativeLayout >
</RelativeLayout>
<LinearLayout >
</LinearLayout>
</LinearLayout>
</ScrollView>
Scrollview must have only one child to it. So I created only one LinearLayout child and add your rest code in it.

just add android:clipChildren="false"to your parent animated view and animation works outside of view.

Hiding specific view in an activity

i am making a kind of survey app . i want to hide specific views from the user till he clicks a button.
Can anybody tell me what to do ?
i would be grateful if anyone could help me on this.

You can change the status of the views programmatically.
You should use view.setVisibility(View.GONE) if you want to remove the view from the layout, and view.setVisibility(View.INVISIBLE) if you want to hide it.
To put them back , use view.setVisibility(View.VISIBLE).

try using setVisibility(View.GONE) initially
and onClick use setVisibility(View.VISIBLE)

Sometimes when you just hide a view or set the alpha to 0 it can still be clicked on or touched. Best thing to do is probably to move it on and offscreen. Moving it offscreen:
yourLayoutParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
yourLayoutParams.leftMargin = (int) screenWidth;
yourLayoutParams.topMargin = (int) screenHeight;
yourView.setLayoutParams(yourLayoutParams);

Is there a generic way to display progress bar over Views in Android?

I have seen numerous posts on how to display progress bar while the data loads in the background. All suggestions requires we manually place a ProgressBar in the layout xml and then use an AsyncTask to show and hide the ProgressBar and the View in question.
However, I would like to make a generic class which creates the ProgressBar programmatically at runtime and place it exactly over the view in question and maybe also slightly shade or blur the view while the ProgressBar is displayed. Had this been a Swing application I would have painted my progress bar on the "glass pane" of the view after slightly shading it with gray. In that case since the progress bar is the child of the same pseudo parent hence I could easily position that as centred.
In Android UI toolkit I am not aware of any such "glass panes". How do I achieve this effect?

Make a BaseActivity that you derive all your Activities from (same goes for Fragments).
Give it something like
protected void showLoading(){
ViewGroup content = findViewById(...);
content.setVisibility(Visibility.GONE);
ViewGroup root = findViewById(...);
root.addView(new ProgressBar());
}
Gotta make sure all your layouts have a ViewGroup for root and one for content, which otherwise might not be necessary and bloat layouts, but thats how I do it and it works fine.
Above is pseudocode of course, but you get the idea.
There's also this libary: http://www.androidviews.net/2013/04/progressfragment/, but I don't think it's necessary to import a library for that task.

Unfortunately you have to create this functionality. I always do this by creating a class from a framelayout and then place my imageview inside with my progressbar ontop. I then create an interface I use as a callback so that when said process is complete and the data is finished being processed I get my callback and I hide the progressbar. I use a framelayout because its the easiest view to use to "stack" views ontop of one another by simply placing them inside the FrameLayout. You may also need to place views inside the frame inside of a relativelayout with the width and height set to match parent so you can set the layout_centerInParent to true on your progressbar so it sits nicely inside your compound view.

Well, I'm not sure I get the question right, because it seems easier to me than it might be. But anyway:
To instantiate programmatically a progress bar, you need to do the following in your activity:
ProgressBar pb = new ProgressBar(this);
((ViewGroup) this.findViewById(R.id.view_that_will_contain_progressbar)).addView(pb);
This will add the view to the ViewGroup view_that_will_contain_progressbar. This ViewGroup should be a FrameLayout if you want to overlay over other information.
Tip: if you want to customize your ProgressBar, you can declare it in a layout file, and do the following to instantiate and attach the PB (still in your activity/fragment) :
this.getLayoutInflater().inflate(R.layout.progressbar,parent);
with parent refering to the parent you want to attach it to.

Android waiting for UI Thread

For testing purposes, I need to get the coordinates of all visible views on the screen. However, when checking the output, it seems the UI Thread is not done drawing/positioning/applying settings to all the views yet. Some views are 0x0 pixels while they should be (and they are on both the emulator and a physical device) visible. Some bottom aligned buttons are positioned like stairs, et cetera.
Q: how can i wait for the UI Thread to complete drawing (or at least wait for like a second, that should be more than enough), so the coordinates of all visible views are accurate?
I suspects it's something with Threads, but I couldn't find any definitive answers. As of yet, I do not have any self-declared threads.
Edit: I use onBackPressed to make a bunch of views visible, then capture that in xml, make the previous views invisible and other views visible, capture that in xml, etc. I iterate trough a few different combinations of views and "xml-screenshot" each combination.

LinearLayout layout = (LinearLayout)findViewById(R.id.YOUD VIEW ID);
ViewTreeObserver vto = layout.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
this.layout.getViewTreeObserver().removeGlobalOnLayoutListener(this);
int width = layout.getMeasuredWidth();
int height = layout.getMeasuredHeight();
}
});
You'll need to adjust this to work with your layout, and add an ID to the basic parent layout.
By using a ViewTreeObserver, you can get to know when your layout has finished drawing, and run your required code then