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Android Show Images while maintaining Aspect Ratio

I am working on an App which shows images (by capturing using camera or choose from gallery) in some activity. The problem I am facing is showing images of different sizes. The actual size of image is very big even those which are captured by camera of same phone are large in size. So if I show them in an ImageView the get stretched.
I have seen in some apps like Facebook, when image is displayed in Full Screen mode, it maintains the aspect ratio I guess. The whole image, whatever its size may be, is shown in the screen but it doesn't get stretched. The image automatically adjusts its height and width as per the need. How to achieve the same functionality?
How to make ImageView which would be able to adjust its height and width (maximum already defined) as per the need.
<ImageView
android:id="#+id/image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:scaleType="matrix"
android:src="#drawable/defaultimage"
android:padding="10dp" />

You need a different android:scaleType in your layout. The ImageView.ScaleType documentation lists the different ones that are available. It sounds like you probably want to change matrix to fitCenter in your example.

How to keep the aspect ratio of a foreground image?

I currently have a FrameLayout with a background and a foreground image. The foreground image has transparency using alpha in order to see through and watch the background below.
The foreground image needs to mantain the same aspect ratio of the original bitmap because consists of a trasparent circle in a black screen, much like a spyglass effect. I'm looking for any resolution compatibility.
Unfortunately, I am incapable of achieve this and the foreground shows always its circle stretched.
This is part of the XML code:
<FrameLayout
android:id="#+id/layout_parent"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#drawable/background"
android:foreground="#drawable/foreground"
android:foregroundGravity="center|fill_horizontal"
>
I am also trying to solve my issue providing two diferent images, one with 4:3 ratio and the other with 16:9 ratio, each one in a different drawable folder with the long and notlong qualifiers.
/drawable-long/foreground.png (16:9 aspect)
/drawable-notlong/foreground.png (4:3 aspect)
Still with no success.
Do you have any idea of how to get this effect?
Thanks for your time.

Change this attribute in your FrameLayout:
android:foregroundGravity="center"
This will place the foreground drawable in the center of the FrameLayout, not changing its size.
"center|fill_horizontal" will place it in the center and stretch its width to fill the FrameLayout width, which is clearly not what you want.

I don't believe you can change the scale type of either the foreground or the background. What I would recommend is to either:
Place an extra ImageView in your FrameLayout to serve as your background, and use the src and scaleType attributes to handle the image and how it scales.
Since it's a simple black background with just a transparent circle, you could convert that into a 9-patch, making sure to stretch it evenly around the circle. The circle will not scale, but the black area will extend to fill the view.
Number 1 is my personal recommendation if the circle needs to scale as well.

TextView dp does not scale with screen size

I am attempting to create a textView that will take up a large portion of the top center part of the screen. Ideally, setting the text size in dp would allow the textView to remain the correct relative size (taking up about 70% of the width of the screen, and maybe 20% of the top). It looks correct in the layout editor, and in the emulator at HVGA resolution. However, when I test it at higher resolutions (on my tablet, or emulating a 720p display) the text takes up a very small portion of the top center part of the screen. (maybe 30% width instead of 70%, and it doesn't seem any larger vertically).
Is there a way to scale text to correctly increase relative size with resolution?

Set the layout_width as fill_parent, which will make it spread across the screen for all devices.
Add some padding on left right and top which seems suitable.
The padding might seem different for different screens but still this might be a better solution.

set
android:layout_width="match_parent"
edit:
check this out
Auto Scale TextView Text to Fit within Bounds

Positioning images to fit all size screens

I'm having a problem with positioning images,I need to position a lot images over another larger background image.
An image Like this
I have tried Absolute but it does not keep the position of the image say I wanted to put a clip art image of a board pin over the background image and need it pointing at a sun and when it's clicked I get a popup dialog,
but then when I change the size of the emulator screen the clip art image is not at the same position I wanted it on the background image.
I first tried just putting the clip art on it with a image editor and used onTouch Listener but that didn't work out when I changed the size of the screen with the x and y coordinates. And tried Absolute Layout and that doesn seem to keep the position.
any ideas would help me big time thanks

AbsoluteLayout is deprecated, so it's probably best to use relative layout alongside with dp.

You could use relative layout so you can use layout_below="#id/view1", android:layout_toRightOf="#id/view2", and android:layout_toLeftOf="#id/view3". You can also use android:layout_marginLeft="10dip", android:layout_marginRight="10dip", android:layout_marginTop="10dip", and android:layout_marginBottom="10dip" to move the views left/right and up/down relative to their current positions. There is also ALIGN_PARENT_LEFT, ALIGN_PARENT_RIGHT, ALIGN_PARENT_TOP, and ALIGN_PARENT_BOTTOM. Click here for more properties.

You can manually calculate visible width and height of the image by using its drawable's getIntrinsicHeight() and getIntrinsicWidth() and then set Image's scaleType to FIT_XY (this saves image's ratio, and also makes its size correct, while FIT_CENTER does not).

Android: How to prevent image from being scaled in ImageView or ImageButton?

How can I prevent my bitmap from being scaled automatically in an ImageView or ImageButton if the view or button is stretched using "fill_parent" or using "weight"?
This will be useful, for example, to create a 4-button toolbar at the top of the screen where the buttons are equally spaced, but the images inside the buttons keep getting streched even if I use scaleType="center", which should prevent scaling according to the doc, but it doesn't.
Any insight is appreciated!
Thanks,

I have found that when using android:background automatically scales the image you are using there to the size of the View.
I tried using the android:src to put the image in the view. The image did not scale, but I could not get the image to center relative to the size of the View.
So I tried making the whole Button it's own relative layout and this is what I used:
<RelativeLayout android:id="#+id/RelativeLayout01"
android:layout_height="fill_parent"
android:layout_width="fill_parent">
<ImageButton android:id="#+id/ImageButton01"
android:layout_height="fill_parent"
android:layout_width="fill_parent"></ImageButton>
<ImageView android:id="#+id/ImageView01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/cardback1"
android:layout_centerInParent="true"></ImageView>
</RelativeLayout>
The ImageButton is in the background and will always be the same size as the layout.
The ImageView however will always stay centered in the RelativeLayout and will not scale.
This way the RelativeLayout itself can grow and move and the Image on top of the button will always stay the same size, but the button will grow. The image will however shrink if the Layout becomes smaller than the image itself.
I think that's what you were looking for. There may be a better way to do this, but this is all I can come up with right now.

Simply modify your drawable, apply a larger transparent background. Say my drawable in hdpi is 41*48 px icon.png . I created a new image 60*60 px with a transparent background , copy-paste the previous icon.png and save under the same name. This way you don't need to touch your layouts .
Then you can check the button zone larger if you apply a non transparent android:background:
<ImageButton android:id="#+id/widget_open"
android:src="#drawable/icon_widget_arrow_up"
android:background="#ff777777"
android:layout_height="wrap_content"
android:layout_width="wrap_content"></ImageButton>
Apply the previous and new drawable to android:src , you should clearly see ImageButton area.
By the way, I am running the app in compatibility mode.

If the image is scaled, make sure you are not running your app in compatibility mode (for instance if you target Android 1.5/1.6 without supporting multiple densities and you run the app on Android 2.0.)