I wanted to know if it was possible to precisely position widgets on Android using XML files? From my experiments, precise position seems impossible via XML. Programmatically, I'm able to position things perfectly based on the device width and height. However, using XML and dip values, things seem to fall apart. Here's one example of what I mean.
Mark Murphy, on an article, wrote:
Some developers, perhaps those coming from the "drag-and-drop" school
of UI development, think first and foremost about the positions of
widgets. They think that they want certain widgets to be certain fixed
sizes at certain fixed locations. They get frustrated with Android
layout manager (containers) and may gravitate to the deprecated
AbsoluteLayout as a way to design UIs they way they used to.
That rarely works well even on desktops, as can be seen by
applications that do not handle window resizing very well. Similarly,
it will not work on mobile devices, particularly Android, with its
range of screen sizes and resolutions.
Instead of thinking about positions, think about rules. You need to
teach Android the "business rules" about where widgets should be sized
and placed, with Android then interpreting those rules based upon what
the device's screen actually supports in terms of resolution.
source
This leads me to believe that precise positioning is difficult with XML files. This is important for my app because I'm laying out widgets on a background image so that these widgets need to be placed exactly on a particular area so that the overall UI looks good. The aspect ratio needs to be preserved across resolutions. Can I do all this using XML files?
Thanks! Any help is greatly appreciated!
Yes you are able to pixel by pixel position your views using an absolute layout.
Last time I checked, which was a while ago, those drag and drop interfaces actually created one for you. (Actually just checking for the link seems that this class has been deprecated.)
However, I highly advise against using them. The reason is because you are coding for so many different screen sizes that providing pixel by pixel dimensions will certainly cause problems across devices.
What I would recommend is using a RelativeLayout. I actually use this type of layout for everything that I can. It lets you put your items to right of, or above and below other elements. This combined with padding and margin options in DIP (density independent pixels) should let you create anything that you want. And it should look nice on most devices.
Related
I have a screen design where the text is above the wave.
This is the original design.
but when I try to do it in different Android screen size, I get this
The text is not part of the background.
Does anyone have any suggestion on how to work around this issue? Should I make the text part of the background?
If this is a rather design-orientated question, then I want to share my thoughts:
Embedding text into images is something that I as a developer would try to avoid. This got several reasons:
Text embedded in images cannot be scaled using the built-in Android text size option. When using a regular TextView, it is recommended to specify the text size using sp standing for scalable pixels, which take the user preference for Android-wide text size into account. See this question for more details.
Text embedded in images cannot be found by the Android Accessibility framework (for example, Text-To-Speech for blind people).
Images that have text embedded are really bad to maintain from a developer perspective. You need to provide several resolutions, several languages, and optionally different images for bright or night mode in Android. This leads to a huge amount of resources that is unhandy.
You need to carefully test and configure images with included text, because there might be devices with unusual resolution leading to distorted images or text.
I'd personally prefer using a regular TextView for the text and let the surrounding layout handle the position of the TextView. ConstraintLayout is really flexible doing that. You could also just use two or three different layouts to separately configure in each layout on how the TextView should be positioned. Depending on your development framework, Android could even automatically pick the right layout, depending on the device size.
Hope this gives you an idea.
I want to get into mobile game development but before I get started I want an idea of what the process is like so I can choose the right tools.
Obviously screen resolution is the most obvious, but what other things have to be changed so it will work on multiple phones?
This is an enormous topic. The most basic design is to have a rectangular play area that can be stretched to fit the screen you are using. Whether you keep your original aspect ratio or "match_parent" for both dimensions is up to you.
You've recognized that that won't take full advantage of screens of different resolutions so many courses and tutorials will walk you through learning to design a relative layout that will arrange and size some elements according to the available space and other elements according to how much space the content needs. You'll also eventually provide images of different resolutions that will be used for different screen densities.
I recommend you jump right into game development before understanding this topic fully. There are many intricacies that you'll come to understand as you work with them.
After some years of Android development, i took months wondering why should i use xml layouts to make the UI of my Android App.
I understand that part of MVC and real-time graphical interface design.
If im wrong please take me out of ignorance and forgive me but , I´m Unable to set a view´s position, exactly, 8% of screen width for margin and 70% of screen width for width, for example.
Creating the UI in that way and taking care of screen aspect ratio ensures the app will look proportionally exactly the same in all devices.
As this post sums it up, we are told to use dip units and a nice bunch of xml files for every layout of our app if we want to support different screens. (Why they call it density-independent if we have to make it different for each screen density?)
But, even doing that, as (again) the Google Doc says
The ratio of dp-to-pixel will change with the screen density, but not necessarily in direct proportion.
And in place of not necessarily they should say mostly never looking at the incredible number of different devices. Depending of your project, this may be a problem. (Or do you want your client looking at your "slightly-decomposed" UI on a who knows chinese device)
I could ask the same for the image resources, but that whould be another question, i use to put the highest resolution on -nodpi then downscale by code to screen-width-dependent desired size, instead of putting 10.000 images at all resolutions.
Creating the UI in that way and taking care of screen aspect ratio
ensures the app will look proportionally exactly the same in all
devices.
This is the way Apple does it, and this why when you open a folder on a 9.7 inch iPad with beautiful retina display, it only displays 9 icons.
A tablet is not just a bigger phone. It's really not. Also, iOS devices have mostly the same aspect ratio, so that's how they took care of the aspect ratio.
On Android however, you can't just say that you "took care of the aspect ratio" problem and that this problem magically goes away. Your best bet is to use Android best practices to handle aspect ratios correctly.
That being said, don't over do it either. You don't need to use all 8 density buckets for instance. Look at the official dashboard to see what devices people are actually using, before you try to optimize for every scenario possible.
Also, you don't have to listen to Google all the time. For instance, I am sure that Google would love that you translate your application so that it's available in more then 68+ different languages worldwide, but what's good for Google is not necessarily good for you. Android actually lets you choose the tools you want to use to make your application. They don't force you to use any particular one.
Actually I need some suggestion like Designing screens for android mobile as well as tablet. As of now im creating two different folder for xml one is for mobile and another one is for tablet. Im placing images in 4 different images with 4 different resolution like (160 dpi, 240 dpi, etc). so am i going in right way or i need to change the way of designing. Thanks.
When designing for different devices it is important to test whether there is a necessity to create different layout files for the different devices. If you find that you do want that then there is plenty documentation online about it. Read these first:
Designing for different screen sizes
Guide lines
More android screen size documentation
Each of these links explain the new methodology of designing for multiple screen sizes.
A few tips on top of the already answered question that I gained by experience:
Use #dimen everywhere you have to specify a width/height but in general, avoid specifying them if you can. This way, you can override the dimension based on the available DPI and don't have to replicate your layouts.
Use LinearLayout wherever you can and use weights to determine how things should be drawn. Other layouts like relative layout are fine as long as they're used for positioning (isLeftOf for instance) as opposed to making a certain space available.
Use fragments wherever you can. It's much easier to work with self contained fragments. In general, avoid having any UI logic in your activities and let the fragments handle them.
Use the Android Asset Studio (http://romannurik.github.io/AndroidAssetStudio/icons-actionbar.html#source.space.trim=1&source.space.pad=0&name=ic_action_example&theme=light&color=33b5e5%2C60) which will take care of resizing your images for you. It's been very valuable to me. Have a look at these other projects too. They can help you in many aspects when designing your UI: http://romannurik.github.io/AndroidAssetStudio/
Even when you do all this, you may come across a scenario where you really do need to write a different layout for tablet and phone. If this is the case, as long as you've created everything in self contained fragments, it's much easier to switch fragments or even use the same fragment code with different layouts (as long as they contain the same UI elements) depending on the dimension. It would also be advisable to use the trick here (Determine if the device is a smartphone or tablet?) to determine if you're running on a large/small tablet or a large/small phone.
All in all, it's a little bit painful developing and testing your app on all the available device sizes but as long as you follow the above points, you'll have an easier time.
I have been learning android development and I am still new to this.
I have already designed many apps for iOS.
Is there a better way to have my layouts as easy as iOS?
because in iOS I only have to drag and move it wherever I want . Where in android I have to insert tables and edit XMLs, which I find very confusing and not flexible to deal with.
I have read and watched many tutorial and still find it a bit difficult to deal with
Thanks
There is a layout editor for Android that you can use in Eclipse. Is that what you're looking for?
http://developer.android.com/guide/developing/tools/adt.html#graphical-editor
The short answer is NO. The long answer is that this is how it's done on Android, and it's much more flexible than the iOS method. Just imagine making Android app the iOS way and support screen sizes such as 240x320, 320x480, 480x800, 480x854, 540x960, 600x1024, 720x1280...and so on, and it's easy to realize that it would be an impossible task. This is almost certainly why Apple went with "Retina Display" with exactly 2x the pixel density and exact same screen dimension (3.5") - because doing anything else would mean that all the apps would need to be designed specifically for the new screen instead of just providing images with a #2x postfix.
So, instead of absolute positioning and sizing like the iOS, XML is used in Android where designers are tasked to come up with one or more layouts that can support this diverse range of screen sizes.
You can use Eclipse Layout Editor for Drag and Drop with absolute layout. But using absolute layout is not a good practice because in iOS screen size is fixed for all device but in android there are different screen size device are available and if you design a layout considering a single screen size it will be messed on another screen size device. You must follow the norms to create a layout go through this link for more detail.
http://developer.android.com/guide/topics/ui/layout-objects.html