Develop Reference

android different dimens not working

I have four dimens.xml files in my values folder and I have different values for different dimens.xml files.
for example, in dimens.xml(hdpi) u_video_width is 306dp and dimens.xml(xhdpi)u_video_width is 404dp.but this values not working, because when i run my app in Nexus S (480X800) hdpi model genymotion
This is what my View looks like:
[![This is what my View looks like][1]][1]
As I said in hdpi dimens folder, I have 302dp but I have different width when I run my app (in XML activity file)
this is a my XML code
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#D53362">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true">
<VideoView
android:layout_width="#dimen/u_video_width"
android:layout_height="#dimen/u_video_height"
android:id="#+id/video_view"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
This is a my dimens xml files
Nexus S has 480X800 resolution and i want to my VideoView to have 302dp in hdpi resolution and another resolution--another dpi how I can solve my problem?

To make same dimension appear the same on higher dpi devices android multiply these dimension with a constant ie
for mdpi it is 1x
hdpi 1.5x
xhdpi 2x
xxhdpi 3x
So in your case it is 306 * 1.5 = 459px
reset of the space (14dp ~35 px) is available on both sides of VideoView
Please refer android developer page
At least this is what I understood. Hope it helps you.

As far as I've understood, it seems it's working right. Your screen is 480px wide and your VideoView is 306dp(in a hdpi screen ~453px), and as it's centered, it remains a bit of margin.
If you want the same dp in another resolution, just remove u_video_width from the other files.

How to add more dimens.xml files in android?

I have an LinearLayout in my xml file for my UI.
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="170dp"
android:gravity="center_vertical|center_horizontal">
<ImageView
android:layout_width="fill_parent"
android:layout_height="70dp"
android:gravity="center_horizontal|center_vertical"
android:src="#drawable/menu_profile_icon" />
</LinearLayout>
I specified the height of Layout in dp. My GUI is different in different emulators . It is good in Nexus 5 emulator but in Nexus S emulator it is not correct . My LinearLayout is out of the screen in Nexus S emulator . What is the solution for it ?
I tried using sp also, but no use,
Thank You.

The android system will choice the right dimens.xml from the "values" folder according the device characteristics.
Some Characteristics:
Screen Density
Screen Size
Screen Orientation
Example:
Device A is a HDPI with a LARGE SCREEN.
The folder name should be:
values-large-hdpi
You have to build the dimens with specific values for each set.
Like the set of Devices with a large screen and XHDPI.
http://developer.android.com/guide/practices/screens_support.html
http://developer.android.com/guide/topics/resources/available-resources.html

Android - ImageView - Multiple Screen Support - Set height/width as dp or match_parent/wrap_content?

I am currently trying to adjust my Android App so it will look and feel similar on multiple screens/devices.
I know by now that a major part in this is to provide multiple image sizes for every image file according to the x1, x1.5, x2, x3, x4 ratios for mdpi, hdpi, xhpi, xxhdpi and xxxhdpi respectively, and I have finished doing so today.
After doing this, I have defined Density independent Pixel dimensions in the #dimen.xml values resource that correspond with the actual image sizes in pixels of the MDPI resources. Subsequently, i have set the imageviews in question's layout_width and layout_height to this dimension.
I am currently at a loss, however, as to why my application still looks significantly different on an MDPI emulator than it does on an HDPI emulator. To highlight what I mean, I'll provide the following screenshot showing the HDPI and MPDI emulator next to one another (left is HDPI (4" WVGA Nexus S) and right is MDPI (5.4" FWVGA)). I want both of them to look like the MPDI version, but what I've done so far apparently isn't working.
I have three theories of my own as to why this is not working the way I intend it to:
1. I am not supposed to set ImageView layout_width and layout_height to a dp value, but rather match_parent or wrap_content (?) (and change the structure of my .xml layouts in the process).
2. I am not only supposed to define multiple drawable resources, but also multiple layout resources for different screen sizes (?).
3. I have misunderstood the entire idea behind how this is supposed to work (?).
I will also give you an example of one of the list items that can be seen in the first screenshot (#drawable/phone_speed_icon is a 64 x64 pixel resource in MPDI and a 96x96 resource in HDPI, and #dimen/icon_attribute_size is 64dp):
<LinearLayout
android:id="#+id/llSpeed_PreSession"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:paddingBottom="10dp"
android:paddingEnd="20dp"
android:paddingStart="20dp"
android:weightSum="100">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="#dimen/icon_attribute_size"
android:layout_weight="20"
android:weightSum="100">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="70"
android:gravity="center"
android:orientation="vertical">
<ImageView
android:layout_width="#dimen/icon_attribute_size"
android:layout_height="#dimen/icon_attribute_size"
android:src="#drawable/phone_speed_icon" />
</LinearLayout>
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="30"
android:gravity="center_vertical"
android:paddingStart="10dp"
android:text="Speed"
android:textAppearance="#android:style/TextAppearance.Large"
android:textColor="#878787"
android:textStyle="bold" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="80"
android:gravity="center">
<android.support.v7.widget.SwitchCompat
android:id="#+id/swSpeed_PreSession"
android:layout_width="wrap_content"
android:layout_height="match_parent" />
</LinearLayout>
</LinearLayout>
In the end, I have four questions that I'd like answered:
1. How do I make the list items in screenshot 1 look the same on MDPI devices as HDPI devices? Does this have anything to do with one of the three theories I mentioned earlier?
2. Why is the header text ("What do you want to measure?") wrapped on one device, but not on the other? They use the sp unit (via android:style/TextApperance.TextApperance.Large)?
3. Shouldn't everything be more spaced out on an HDPI device (if anything) rather than less spaced out? The HDPI emulator looks as if it "has got way less pixels available", if you can understand what I'm saying even a little.
4. How do I make the Fragments on the second screenshot look the same? Or should i not even want this, because the HDPI is (for some reason) physically smaller, which is why the layout is less spread out?
Anyway, I have been at this all day and the more I read the more thouroughly confused I get, so any help is greatly appreciated!

You have the option to create multiple dimens.xml files depending on a variety of factors. Here you'll see what my current project looks like with the various dimens.xml files in Android Studio based on screen width.
However, you can have different requirements for each dimens file you want. For example, you can create dimens files for each density:

Layout for tablets

The attached layout which works correctly for a phone (Samsung Infuse), but it does not show
layout correctly when the app is uploaded to a tablet (Nexus 7). The button sizing is incorrect. How can I fix this?
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/"
style="#string/menu_settings"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#drawable/gecko25"
android:gravity="center_horizontal"
android:orientation="horizontal"
android:textAlignment="center"
android:visibility="visible" >
<Button
android:id="#+id/link1_btn"
android:layout_width="98dp"
android:layout_height="wrap_content"
android:minHeight="58dip"
android:minWidth="98dip"
android:text="About"
android:textStyle="bold" />
<Button
android:id="#+id/link2_btn"
android:layout_width="98dp"
android:layout_height="wrap_content"
android:minHeight="58dip"
android:minWidth="98dip"
android:text="Experience"
android:textStyle="bold" />
<Button
android:id="#+id/link3_btn"
android:layout_width="98dp"
android:layout_height="wrap_content"
android:minHeight="58dip"
android:minWidth="98dp"
android:selectAllOnFocus="false"
android:text="Bulacards"
android:textStyle="bold" />
</LinearLayout>

Make different layouts for different densities. ie, place the same xml file in layout-hdpi,layout-xhdpi,layout-tvdpi
To create those folders in res/layout follow these steps:
Right click on layout folder --> new-->other-->Andorid xml layout-->next-->give the filename(must be same in all densities)-->AvailableQulaifiers tab select density--> move it to chosen qualifiers with the help of arrow in between--> there select for what density (medium high tv)--->finish
Like for example:
Nexus S and Nexus one ---> hdpi
Galaxy Nexus ----> xhdpi
Nexus 7 ---> tvdpi
and give heights and widths for the Button.. best practice is to set them to wrapcontent , if for your scenario it requires height follow the above steps. and give height and width such that different for phone and tablets which comes under different densities

It's not recommended that you use tvdpi for Nexus 7 screens.
See this:
http://android-developers.blogspot.com/2012/07/getting-your-app-ready-for-jelly-bean.html
Probably the best way to detect 7" tablets (like the Nexus 7) is to use the qualifier:
layout-sw600dp
And the qualifier for 10" tablets:
layout-sw720dp
You might want to try specifying the button sizes in sp rather than dp as they may need to bigger or smaller if the user changes the default font size but wrap_content and/or use weights are usually best.

Unexpected behaviour while setting a image from res folder to an image view in android

I am using an imageview in my xml and setting an image from res/drawable-xhdpi to it. My image is of 354x404 in size and when i am running the code on a 10" samsung tablet, it showing the image as 177x202.
Here is the code which i am using:
<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"
android:baselineAligned="false" >
<ImageView
android:id="#+id/img_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="#string/app_name"
android:src="#drawable/android1" />
</LinearLayout>
Here is the image which i am using:
And this is the screenshot of the tablet:
Please tell why it is happening and what is the solution to resolve this problem.
Update: when i putting this image in "res/drawable" folder instead of xhdpi, it showing the image correctly i.e. 354x404.

Edit after comments:
The ImageView will render the image inside of it at the correct resolution for the device. As per the documentation on providing resources, you must make sure that you provide resources at the correct DPI for each of the resolution types. Android will pick the best resource resolution for you, but if only one resource exists then it will pick that one and try to render at the device resolution.
Samsung tablets, while they have a large screen, are MDPI (the Galaxy Tab 2, at least) which is the standard density even though it has a large screen. Resources for it should be placed in res/drawable.