Develop Reference

Scale a ImageButton

I have an app that have an activity with 3 imagebutton and a banner ad below. Something like this...
The ImageButton layout sizes are wrap-content, and each source is a png that i've made.
Now, when i've tested in a small screen the bottom one is behind the banner ad.
I want to scale the ImageButtons dending on the size (mainly the height) of the screen.
Can anyone tell me a correct way to do it?
I have to make small png sources that fits on a small screen and then make more drawables with minimal screen width qualifiers? 320dpi and 480dpi its a really big margin, i will have to make some more folders in between.
Thank you all in advance!!!

if you dont domain Constraint Layout, maybe you can try to use a LinearLayout inside your main layout with weight to divide the screen... something like below, it may work:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:weightSum="4"
android:padding="10dp">
<ImageButton
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:src="#drawable/..."/>
<ImageButton
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:src="#drawable/..."/>
<ImageButton
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:src="#drawable/..."/>
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:src="#drawable/..."/>
</LinearLayout>
</RelativeLayout>
Just adjust it as you want... Hope this work :)

You don't need to create separate images, you can use ConstraintLayout and it will manage the sizes for you automatically. I have tested the code below and it seems to work fine. Have a go at it:
your_activity.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<ImageButton
android:id="#+id/imageButton1"
android:layout_width="wrap_content"
android:layout_height="0dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="#id/imageButton2"
android:background="#color/white"
android:src="#drawable/image_1"/>
<ImageButton
android:id="#+id/imageButton2"
android:layout_width="wrap_content"
android:layout_height="0dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/imageButton1"
app:layout_constraintBottom_toTopOf="#id/imageButton3"
android:background="#color/white"
android:src="#drawable/image_2"/>
<ImageButton
android:id="#+id/imageButton3"
android:layout_width="wrap_content"
android:layout_height="0dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/imageButton2"
app:layout_constraintBottom_toTopOf="#id/bannerContainer"
android:background="#color/white"
android:src="#drawable/image_3"/>
<!-- Whatever container your banner is in -->
<RelativeLayout
android:id="#+id/bannerContainer"
android:layout_width="match_parent"
android:layout_height="80dp"
android:background="#000"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintBottom_toBottomOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
Note:
I have added the background colors just to test out. The main point to focus on for you is that the height of the ImageButton is 0dp for all, and the constraints manage the height automatically.
The good part of ConstraintLayout is that you don't need to specify different weights like you would in a LinearLayout, so you can have images of different heights and it will work just fine.

If you are using css you can use the property unit vh (viewport height). The measurement is a percentage of the viewport/screen height. For example height: 10vh; width: auto; will render the element height as 10% of the screen height, without distorting your png. If you use this measurement for the four elements shown, they will all appear on the screen at the same time if their values add up to 100.
https://www.sitepoint.com/css-viewport-units-quick-start/

DP is display different layout in different screen

I have created a layout and define following Xml in layout file.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.kirmani.myapplication.MainActivity"
android:orientation="vertical"
>
<ImageView
android:layout_width="match_parent"
android:layout_height="100dp"
android:background="#color/colorPrimary"
/>
<ImageView
android:layout_width="match_parent"
android:layout_height="150dp"
android:background="#color/colorPrimaryDark"
/>
<ImageView
android:layout_width="405dp"
android:layout_height="260dp"
android:background="#color/colorAccent"
/>
</LinearLayout>
This is filling my whole screen perfectly in Nexus 4 screen. but when i preview all screens, its giving very weird look in some screens.
I am using DP, it should maintain same display according all screens, but it is not working like that. Kindly guide me..

Actually dp maintains same display according all screens. It's because every device are not supposed to be same width in dp. Some devices has 480dp, some of them 360dp etc.
If you want to your image fit your width, you must use
<ImageView
android:layout_width="match_parent"
android:layout_height="260dp"
android:background="#color/colorAccent"
/>
do not use fixed dp.
EDIT:
If you want to height fill up, use this:
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorAccent"
/>

Your 3rd imageview width should be match parent. Like this
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorAccent"
/>
instead of
<ImageView
android:layout_width="405dp"
android:layout_height="260dp"
android:background="#color/colorAccent"
/>

We are talking Android ABC here. You need to understand how this works instead of looking for concrete answers to concrete problems, as I already recommend you here.
Every device has an specific dimension in DPs. Nexus 4 is 384x640 but is the only one in your image with those dimensions. Please realize that is not that "is looking weird on some screens", in fact is gonna look weird on all screens that are not 384x640. For instance, the Nexus One in your image (which is 533dp x 320dp) is not working as expected, but is more difficult to realize because what is wrong is outside your view, but the views are bigger than the screen. Same with the Nexus S.
If you are trying to get a view from edge to edge (all the screen width), then use match_parent. Do not specify a size in DPs.
If you are trying to distribute views horizontally or vertically, please use an specific ViewGroup and/or weights, or you can use the Percent Support Library for doing things like this or this. Take a look at this tutorial for more.
Anyway, here you have your copy&paste code.
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<View
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#color/colorPrimary" />
<View
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1.5"
android:background="#color/colorPrimaryDark"/>
<View
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="2.6"
android:background="#color/colorAccent"/>
</LinearLayout>

Android layout not consistent across devices instead of using dp

Screenshot of first image
Screenshot of other phoneI have a LinearLayout ,RelativeLayout,LinearLayout and a ImageView in it.This is basically a landing page of my app,inspite of using the dp my output is not same on the all device. There is the screenshot of two different phones. Thanks in advance
<LinearLayout
android:id="#+id/lb_LinearLayout"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<RelativeLayout
android:id="#+id/lb_Relative_HomeScreen"
android:layout_width="match_parent"
android:layout_height="450dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="350dp">
`` <ImageView
android:id="#+id/lb_Background_Image"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="fitXY" />
</LinearLayout>
<TextView
android:id="#+id/lb_Welcome"
android:text="#string/welcome"
android:gravity="start"
style="#style/Heading2.yellow"
android:layout_width="match_parent"
android:layout_height="30dp"
android:layout_gravity="start|center_vertical"
android:layout_above="#+id/lb_Descrption"
android:layout_marginLeft="20dp"
/>
...
</RelativeLayout>
</LinearLayout>

You need to create different layout files for the major screen density buckets and screen sizes. This way you will be able to fine tune your layout to look consistent across multiple displays.
You can easily create a new layout for a specific bucket from the preview window:
Click on this icon in the left corner.
Then select Create Other....
A popup window will appear then select from the Available Qualifiers the size item for the different screen sizes of Density for the different density buckets.
After you selected the desired item press the >> key, and you can select the appropriate bucket for witch you wish to create a new layout file.
After this you press ok and the android studio creates for you a copy of the current layout and places it in the appropriate folder for you, all that you need to do is to edit it so that it look the way you want it to look on the specific layout.

You should use ScrollView like this :
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:id="#+id/lb_LinearLayout"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<RelativeLayout
android:id="#+id/lb_Relative_HomeScreen"
android:layout_width="match_parent"
android:layout_height="450dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="350dp">
`` <ImageView
android:id="#+id/lb_Background_Image"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="fitXY" />
</LinearLayout>
<TextView
android:id="#+id/lb_Welcome"
android:text="#string/welcome"
android:gravity="start"
style="#style/Heading2.yellow"
android:layout_width="match_parent"
android:layout_height="30dp"
android:layout_gravity="start|center_vertical"
android:layout_above="#+id/lb_Descrption"
android:layout_marginLeft="20dp"
/>
...
</RelativeLayout>
</LinearLayout>
And to be more compatible with all the devices, try to use "wrap_content" or "match_parent" for height and width. If images are making you to declare dp in your code, then please go through this link :
https://developer.android.com/guide/practices/screens_support.html

Resize ImageView to make entire layout fill screen

I have a screen that contains some TextViews and an ImageView inside a LinearLayout with vertical orientation. I would like the whole thing to fit exactly in the screen (no matter what its size is) where the ImageView is the one that adjusts itself to accommodate this.
I've seen here a few variations of this question (including this) but didn't find anything that really answers my requirement.
So far i've used a solution which is not very "pretty", which is putting the entire LinearLayout inside a ScrollView, and use a custom ImageView that on its onMeasure method calculates the delta between the height of the ScrollView to the height of the screen. If the former is larger than the latter then the delta is subtracted from the ImageView's measured height.
This solution is not perfect and i would really like to know if there is a better one. Im sure there is.
Appreciate your help.
EDIT: here is the layout xml
<com.xxx.widgets.LockableScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:custom="http://schemas.android.com/apk/res/com.venews"
android:layout_width="match_parent"
android:layout_height="match_parent"
custom:scrollable="false"
android:fillViewport="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingLeft="#dimen/login_horizontal_margin"
android:paddingRight="#dimen/login_horizontal_margin"
android:orientation="vertical">
<com.xxx.widgets.ResizableToFitScreenImageView android:id="#+id/login_logo_image"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="#dimen/login_logo_margin"
android:layout_marginBottom="#dimen/login_logo_margin"
android:src="#drawable/ic_logo_and_name"/>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView android:id="#+id/login_username"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"/>
<TextView android:id="#+id/login_password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#id/login_username"/>
(...Other stuff...)
</RelativeLayout>
</LinearLayout>
</com.xxx.widgets.LockableScrollView>
EDIT2: and here's a sketch that i hope will make things clearer.
The sketch is showing 2 different screen sizes cause this solution would need to support also different devices with different screen sizes.

On the ImageView, set android:layout_height="0dp" and android:layout_weight="1". This will cause it to fill the remaining space (more about layout_weight here).
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ImageView
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>

Android layouts and automatic image resizing

My android app currently has two layouts for its splash screen, portrait and landscape. Both use the same simple format - an image that's the same size as the screen, held in a simple linear layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:scaleType="fitCenter"
android:src="#drawable/splash_p"
/>
</LinearLayout>
The image used is 320w x 480h and Android automatically resizes it to fit the screen, irrespective of the screen size of the device. Obviously, the image isn't as sharp when resized for a tablet for example.
I should point out here that my goal is to reduce the installed size of the final application as much as possible, and I'm aware that I could include different layouts and sizes of the same images for each differing screen size.
My splash screen is made up of the app's name in the top third of the screen, and then an image in the bottom two thirds of the screen. In order to save memory, I want to crop the app name and the image into two seperate images, and then display them in a linear vertical layout for devices held in portrait mode. I'll then use a linear horizontal layout of image and then app name for landscape mode.
For the portrait layout I've got this:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical">
<LinearLayout android:id="#+id/linearLayout1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical">
<View android:layout_height="45dp" android:layout_width="45dp" />
<ImageView android:layout_height="fill_parent"
android:src="#drawable/splashtext"
android:scaleType="fitCenter"
android:layout_gravity="center"
android:layout_width="fill_parent"></ImageView>
<View
android:layout_height="35dp"
android:layout_width="35dp" />
<ImageView
android:scaleType="fitCenter"
android:src="#drawable/splashpic"
android:layout_height="fill_parent" android:scaleType="fitCenter" android:layout_width="fill_parent" android:layout_gravity="center"/>
</LinearLayout>
</LinearLayout>
When I display the above in eclipse, it looks ok for smart phones, but the images are not scaled up when displayed on a tablet, although I'm using the android:scaleType="fitCenter" argument. I've tried using dips instead of fill_parent in the imageview layout_width and layout_height but that doesn't work either.
What am I doing wrong? Is there another way to do this?
Thanks
I've edited the question to include this revised XML based on #KaHa6u 's help below. So now I have:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<LinearLayout android:id="#+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<View
android:layout_height="15dp"
android:layout_width="15dp"
/>
<ImageView android:layout_height="wrap_content"
android:src="#drawable/splashtext"
android:adjustViewBounds="true"
android:scaleType="fitXY"
android:layout_gravity="center"
android:layout_width="wrap_content"
android:layout_weight="1">
</ImageView>
<View
android:layout_height="15dp"
android:layout_width="15dp"
/>
<ImageView
android:scaleType="fitXY"
android:src="#drawable/splashpic"
android:adjustViewBounds="false"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:layout_weight="4"
android:layout_gravity="center"/>
</LinearLayout>
</LinearLayout>
Which scales up vertically, but not horizontally, so I end up with tall thin images when the screen size increases.

#basinbasin
I just encountered a situation very similar to the one you explained. I needed to have an ImageView on top of the layout, which had to be stretched ONLY HORIZONTALLY and retain its height when the phone gets into landscape orientation. I succeeded with just this:
<ImageView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:src="#drawable/main_header"
android:scaleType="fitXY"
/>
and, of course, with activity's attribute:
<activity android:configChanges="keyboardHidden|orientation">
Hope this helps. Thank you.

The fitCenter scaleType maintains the original aspect ratio. Have you tried the fitXY scaleType? Matrix.ScaleToFit Documentation

Did you try "fill_parent" as the android:layout_height and android:layout_width values for the ImageView you want stretched?
I guess that the "wrap_content" setting does not let the system know the bounds to which to resize the image. Please try that and let me know of the results.