Develop Reference

TextView above ImageView: Space between the top of the scaled SVG and the bottom of the TextView is scaled

In my application, a TextView is shown above an ImageView which contains a SVG image. Depending on the screen resolution, the ImageView, which is constrained (top and bottom e.g.) by another ImageView, is scaled: thus its SVG is also scaled by decreasing its height (and width, proportionnaly). Thus, the space between the TextView and the ImageView is technically the same than the one in Android Studio but is visually longer.
What I would want is: to keep the same space in Android Studio than on all screen resolutions, i.e.: 8dp.
Example:
In the Android Studio's visualizator, the space is 8dp:
In a Samsung Galaxy S7, I think the space is still 8dp but the SVG has been scaled: the space seems longer.
Proof that the SVG is scaled and that the ImageView is really at 8dp from the TextView:
Do you know how to keep the same space than in Android Studio, whatever the screen resolution?
Warning
I really want the SVG to be scaled (so I don't want, e.g. to set scale: fitXY or something like that). But I also want the space between the bottom of the TextView and the top of the scaled SVG be 8dp on all screen resolutions.

This is a guess but I think that your image is causing the problem.
As you said - your space is the same 8dp all the time but because your image has a white background, when you use a bigger image the white background scales and it looks like the space between your text and image is larger.
You can use some view with non-white background and scale it for testing - I believe that you will see the same spacing regards the view size. If this will be the case maybe try to change your image.

You can use LinearLayout layout with constraints to ensure a fixed proportion no matter what
E.g
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/main_layout"
android:orientation="horizontal"
>
<ImageView
android:id="#+id/img"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="40"
/>
<TextView
android:id="#+id/txt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="60"
/>
</LinearLayout>
So no matter what, in our example, the image will always be 40% of the horizontal space while the text will be 60%. I believe you can apply this idea to your situation

Android Camera Preview centered in an image

I am creating a Camera application where I want to restrict the camera preview to be centered and around 60% of total size of the phone screen.
One way is to have the FrameLayout of Preview with padding so that the usable screen size is restricted , but I also want to show borders (around the corners) inside the restricted area which is not possible in this options.Also it not possible to show padding in percentage so that I can restrict user to 60% of screen size.
Other way is to have a image having a transparent center rectangular area and having border in inner rectangle corners . But I somehow need to restrict the FrameLayout of preview inside this rectangle which I am not able to do . Any suggestions on this option ?
Please also let me know if there are any other options .
Thanks.

Unless I don't fully understand your issues with using android:padding to provide space around your layout, you should be able to use android:layout_margin instead to accomplish the same goal but overcome the problems you mentioned. Adding padding creates space between the border of the View and its content. However, adding margin creates space between the border of the View and its parent, so the content still fills the View itself to the edges. However, you still can't define your view spacing in terms of percentage direct from XML...you would need to define the margin as static or apply the LayoutParams in Java code where you could calculate the required margin based on the current screen size.
Another option is to take advantage of the android:layout_weight property inside of a nested LinearLayout. The calculated weight sum could give you the 60% you're looking for directly in XML. Something like this:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:weightSum="1.0" >
<LinearLayout
android:orientation="vertical"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="0.6"
android:gravity="center"
android:weightSum="1.0">
<SurfaceView
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.6" />
</LinearLayout>
</LinearLayout>
Where the SurfaceView is the location of your Camera Preview, now centered with 20% of the screen on all sides. If you wanted to place things over or under this preview you would obviously want to place this entire block into a RelativeLayout or FrameLayout along with other components.
HTH!

ImageView within RelativeLayout has top and bottom padding

I have a 640px wide, 208px tall PNG that I've placed in my /drawable folder and I'm having a very hard time properly placing it in an ImageView. I want to scale the image so that it maxes out the horizontal resolution, and I want it to scale vertically only as much as it takes to stay in proportion.
The problem I am having is that my ImageView ends up taller than it needs to be to fit the image. The image itself looks perfect; as wide as the screen and in proportion. But the ImageView appears to have padding on the top and bottom. From what I can tell it's the drawable that the ImageView contains that's actually too tall.
I can't post an image because I'm new to SO, but if I did it would be of the Graphical Layout view. When I click on the ImageView the regular blue box shows up around it, but with padding on the top and bottom, the same padding I'm seeing on the device. Even if I drag the blue box to attempt to resize the ImageView, I am not allowed to make it any smaller than it already is (perhaps because the ImageView thinks the drawable is that tall, or something). From what I can tell, this may have something to do with the density of the image...the ImageView ends up being 312 pixels tall (208*1.5) on an hdpi device.
Here is my XML:
<?xml version="1.0" encoding="utf-8"?>
<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/back" android:src="#drawable/categoryheader2"
android:layout_width="wrap_content" android:layout_height="wrap_content">
</ImageView>
</RelativeLayout>
Thanks in advance for any help!

I guess android:adjustViewBounds="true" on the ImageView should do the trick. I recently had a similar problem, when I was trying to scale an image to fit the whole width of the view without loosing its proportions.

did you tried the tag : android:scaleType="fitXY" or android:scaleType="centerCrop" on your ImageView ?

Apply scale to layout in android

I have a RelativeLayout which currently has a fixed size. Widths, heights, margins, font heights of child views are specified so everything looks just right.
I now want to scale the layout (to fit screen size). The layout should scale as if it was a flat image, so everything gets smaller in proportion (fonts, margins etc.)
I made a simplified example, below. Scaled to 0.5, this would display the text "ONE QUARTER" with margin left 200dip and margin top 120dip.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
android:id="#+id/RelativeLayout01"
android:layout_width="1600dip"
android:layout_height="960dip"
xmlns:android="http://schemas.android.com/apk/res/android"
>
<TextView
android:text="ONE QUARTER"
android:id="#+id/TextView01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="400dip"
android:layout_marginTop="240dip"
></TextView>
</RelativeLayout>
Of course, I'm not asking anyone to help me hand code an algorithm to scale all these values: just wondering if there's some simple way to achieve this...
Thanks!

If you just want your app to look ok on another device then specifying things in dip and sp should do the trick.
If you actually want to shrink or expand the scale of your app on the same device then you would have to do it manually, perhaps using themes or styles.

Expand clickable area of an ImageView by using padding?

I have an ImageView, and I want it to be clickable. The image itself is only 32x32 pixels, but I want the clickable region to be larger so it's easier to hit. I was hoping I could set the layout margin values to increase the size of the imageview's clickable area:
<ImageView
layout_width="32dip"
layout_height="32dip"
layout_margin="20dip" />
That doesn't work, what I could do is just recreate the image resource to have a larger transparent region around it. That's a bit annoying because it's hard to tweak if I ever need to change the clickable region. It's not just a single png either, it's a statelistdrawable so I have to resize 3 different pngs if I ever need to tweak the clickable area.
Anything else I can do?
Thanks

Use padding. layout margins are used if for inserting space outside the boundary of the view.
for equal padding on all sides
<ImageView
android:padding="20dip" />
or to set the padding on each side
<ImageView
android:paddingLeft="10dip"
android:paddingRight="15dip"
android:paddingTop="23dip"
android:paddingBottom="12dip" />
Hope that helps !

Instead of resizing the image (Peter Knego's answer) or increasing padding (Saimon's answer) I suggest to set the minWidth and minHeight attributes in combination with scaleType="center":
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:minWidth="40dp"
android:minHeight="40dp"
android:scaleType="center"
android:src="#drawable/your_image" />
That makes sure that small images have at least a size of 40x40dp while the image is not up-scaled if it's smaller. If one day the image is going to be replaced with another image larger than minWidth and minHeight it will not grow larger than 40x40dp as it gets downscaled. Thus a minimum clickable dimension of 40x40dp is always guaranted and the image is always displayed nicely.

Suggestions (never tried it myself):
Create ImageView as large as you want than put image into it without scaling
ImageView.setScaleType(ImageView.ScaleType.CENTER).
Brute force approach: create new larger png that has original image centered and the rest of it is transparent.

Use like below; where width/height is your touch radius
<ImageView
android:id="#+id/editProfile"
android:layout_width="32dp"
android:layout_height="32dp"
android:padding="8dp"
android:background="?attr/selectableItemBackgroundBorderless"
android:src="#drawable/ic_edit"
android:scaleType="fitCenter"
/>
In the above code, I wanted my src size to be viewed as 24dp width/height. And touch radius of 32dp. so I had used padding of 8dp.