Develop Reference

Round shaped image is elongated horizontally or vertically

I have to display a splash image which has a round shaped object (a Ball). The Layout for splash is a simple linear layout with just a single Image view to occupy the full screen.
Image : single image with the size of 1280 x 720.
When my splash screen is shown in the App, The round object is shown in different shape in different screen sizes. I hope the aspect ratio and the resolution is the cause for these elongated images.
Could you please suggest an idea / approach to solve this ?
Do I need to consider the aspect ratio or the resolution or both ?
Finally the ball should look like a ball in all the devices :)
Thanks in Advance.

1) Yes, by default Android will scale your image down to fit the ImageView, maintaining the aspect ratio. However, make sure you're setting the image to the ImageView using android:src="..." rather than android:background="...". src= makes it scale the image maintaining aspect ratio, but background= makes it scale and distort the image to make it fit exactly to the size of the ImageView. (You can use a background and a source at the same time though, which can be useful for things like displaying a frame around the main image, using just one ImageView.)
2)You should also see android:adjustViewBounds to make the ImageView resize itself to fit the rescaled image. For example, if you have a rectangular image in what would normally be a square ImageView, adjustViewBounds=true will make it resize the ImageView to be rectangular as well. This then affects how other Views are laid out around the ImageView.
You can change the way it default scales images using the android:scaleType parameter. By the way, the easiest way to discover how this works would simply have been to experiment a bit yourself! Just remember to look at the layouts in the emulator itself (or an actual phone) as the preview in Eclipse is usually wrong.
Reference : How to scale an Image in ImageView to keep the aspect ratio

set imageView property
scaleType="centerInside"

Add scaled versions of the image with the same file name under folders 'res->drawable','res->drawable-ldpi','res->drawable-hdpi' and under xhdpi "http://developer.android.com/guide/practices/screens_support.html#DesigningResources"

Android fit image to imageview without preserving aspect ratio

I want to fit image to android imageview without preserving the aspect ratio. I.e. I want the image to resize to imageview's size. I know that I can use the image as a background of the imageview to achieve the purpose. But is there any way I can use it as a foreground image of the imageview and fitting it to its dimension?
I have seen various answers and all of them suggest the other thing(image view fitting to the image size).I want to do it via xml.

Of course, you have tried
android:scaleType="fitXY"
I suppose...
Developer - Scale Type
This would scale in both directions (X, Y) independently
(by using the FILL algorhithm, which is - more or less, the same as what it does when setting a background).

Android ImageView scaleType

I have an image to be used a background in activity:
I want this image to fit screen by its height.
It means that for wide-screen smartphones, I want my image to be fit by height and centered:
and for square-screen smartphones, I want my image to be cut:
I use ImageView for the image. What scaleType should I use? Looking at the second figure, I'd say to use android:scaleType="centerInside". But looking at the third, I'd say to use android:scaleType="centerCrop". What is correct?

Your evaluation of the different scaleType's is correct. If you want the whole image to be visible, use "centerInside", or if you want to fill the whole view then use centerCrop.
To use a mix of both, you can set the scaleType in your onCreate() method. Based on the behavior you want to have, you can check the orientation or size of the screen and set the appropriate choice.
imageView.setScaleType(ScaleType.CENTER_INSIDE); // or ScaleType.CENTER_CROP

You can have two layouts, one for each of your configurations. You can then load the proper one at the activity's onCreate() call.

When you fit one side of image to background, you will face with two problems, first one is screen width is bigger than image's width or screen height is bigger than image height.So you will have empty space.
If you do not want to face with resolution problem and you want to fit both side of image to background, you need to use centerCROP.But as i said, if one side of image is not enough to fit background, image gets bigger till it will be filled.

Use centerCrop because centerInside doesn't scale an image in a view and you have to create the image with appropriate height to achieve wide-screened smartphones background filling. Or alternative you could use fitCenter to get uniformly scaled image by both axes which fills the all background.

Scale an ImageView to fill screen horizontally and scroll (if necessary) vertically in ScrollView

I've tried as many permutations of scaleType and fillViewport and adjustViewBounds and layout_* as I can think of and none of them do what I want. They either fill the screen but lose the aspect ration (fillXY), cut off a portion of the image (centerCrop), or scale the image down so it doesn't fill the width of the screen (centerInside, fitStart, fitCenter, center, matrix).
Here is one specific example:
Source image is 222x470 pixels.
Emulator screen is 480x800hdpi in portrait orientation.
I want the ScrollView to fill the entire screen.
I want the ImageView to scale the image so it fills the width of the screen (stretching the source image from 222 wide to 480 wide).
I want the ImageView to preserve the aspect ratio of the source image, meaning its height will have to scale from 470 pixels to approximately 1016 pixels.
Since that won't fit on the screen (it is only 800 pixels high), the ScrollView should kick in. By default the top of the image should show and the ScrollView should allow scrolling down to see the rest of the image.
This is just one example. Ideally I'd like this to work regardless of image size and screen size.
Extra credit if you know a way to do it all within the XML layout.
And before y'all come down on me like a ton of bricks (or bricked cellphones?), I'm aware there are several similar questions on this site (see here, here, here, here, and here) but they are either unanswered or the answers are unacceptable ("use fitXY", which does not preserve aspect ratio, or require specifying exact pixel width/height in the ImageView which is not a general purpose solution to the problem). It'd be nice to get a solid answer to this documented and out there.

Answering my own question in the hopes it helps someone else.
I found a simple functional answer here. The AspectRatioImageView class works where all my XML scaling attempts failed.

Android: scaleType expand to screen

I need to resize several images inside ImageView to screen size.
Currently I use scaleType="centerInside", it works good for bigger images to scale them down to screen size but doesn't expand small images.
All other suggested options crop or deform image. Is there any way to expand images (keeping ratio) via XML or do I have to do it manually in code?

You will be limited in how much you can do from the XML alone. The simplest way to expand a small drawable is to set android:layout_width and android:layout_height properties to what is desired (using density independent pixels dip). android:layout_width="320dip" will expand you to the full width of the screen (in portrait view).
If your images are photos or something with varying aspect ratios, then your only choice may be to inflate the view from code (after determining the correct size).

Just try scaleType="fitXY" . It Will enlarge or shrink the image exactly to the size of image view

Use scaleType="fitCenter" instead.

Try fitStart // Scale the image using START.
android:scaleType
http://developer.android.com/reference/android/widget/ImageView.html#attr_android:scaleType