I understand that android is a completely different thing than browser programming.
But coming from a web development background, I wanted to undertand what fragments are supposed to be used for ?
Are they similar to the concept of iframes in an HTML page having its own UI and can be added to any other page?
If not then what is tje general use-case of android fragments ?
They are reusable parts of your applications. You can have for example two different Activities using same Fragment. You may want to read Fragments Design Philosophy in the android documentation.
Here's also short description from the same documentation page:
A Fragment represents a behavior or a portion of user interface in an
Activity. You can combine multiple fragments in a single activity to
build a multi-pane UI and reuse a fragment in multiple activities. You
can think of a fragment as a modular section of an activity, which has
its own lifecycle, receives its own input events, and which you can
add or remove while the activity is running (sort of like a "sub
activity" that you can reuse in different activities).
Yes, I think you can think of them as the same at a conceptual level.
Related
I am learning android from two resources one from video and one from book +(android developer resources ). Both show how to have multiple views in a different ways. Video one used activity and intent book used fragments. What is the best practice fragment/activity?When to use Activity and when to use Fragment.
You will most likely hear things like
You can have an Activity without a Fragment but you cannot have a Fragment without Activity
You can have multiple Fragments under a single Activity
You can use Fragments to have multiple sections in a single screen
Fragments has its own lifecycle
So I'd give my personal thought and a little bit of scenario based on my own experience on how I would decide which to use based on a given scenario.
Consider a Registration Form where I'm required to create 3 screen features of which contains Basic Personal Info, Financial Information and Online Mailing Information, in this case I would use multiple Fragments under 1 hosting Activity named RegistrationActivity.
Now consider same application where I'm required to create a User Setting Screen it wouldn't make sense if I create another Fragment under that same Activity right?, so that would be a separate context and everything about it will go to another Activity named SettingsActivity
There are more technical things under the hood, but most of the time you will decide which to use based on the use-case you are dealing with.
There is also an up to date architecture namely Modular design where each closely related components are grouped inside a module library, majority of such project will fall under the feature category where most of the time if not all, have single Activity hosting multiple fragments. And going back to my scenario it would be like a Registration Module
Hope it make sense.
Have a look at another similar post
Why fragments, and when to use fragments instead of activities?
Seems fragments reacts to a user event only.
What is the Android component used for, breaking an activity into
multiple sub-components?
Just for sake of maintainability of UI code in Android.
I don't know exactly what you mean by "reacts to user events only". You can also have headless fragments which don't have an UI.
You can use fragments for your intention. You can communicate between the fragments via your activity (which holds the fragments).
Speaking of clean code maybe you want to take a look at the Architecture Components & MVVM
From what I understand, and activity is equivalent to a "page" in a web app.
For example, the list view would be one activity, edit view another activity, and add view a third activity.
While this works as expected, android activities seem to operate as individual apps--the action bar is different for each activity and so are the menus.
Is my usage of activities above correct or should I be using some other mechanism such as swapping out layouts and views?
Fragments are a core part of activities - not that much different. The use of fragments comes since Honeycomb 3.0 and the idea is an option to split the screen in several fragments at once. For example if you look at the gmail app for a tablet - you have one fragment on the left dealing with navigation and then the next fragment on the right is the list of emails.
On a mobile device, viewing area is limited, so you it could be said that fragments sort of behave like an activity - you interact with one fragment, which triggers another and so on and so fort. But in the end you always reference a super activity of each of these fragments - for example when you want to access the context.
So if you just want to wrap web pages in WebViews, stick with activities. If your scenario might involve developing for both tablets and phones, then go for the fragments.
Alternatively, you can read about the design philosophies of both here:
http://developer.android.com/guide/components/fragments.html
Good luck!
Fragments are to be used when you have common feature across multiple activities. From my perspective you should use individual activities as there will be back-end code to support (fetch and validate data, i.e. business logic). This way you have more modular code. Fragments is a new feature from v3.0.
From what I know, Fragments would be a good option to be able use different configurations/real estates on different devices. For example, if you are on a device with big real estate like Tablets or TVs you can display more content in a single activity, on the other hand for a devices with smaller real estate you can show content based on a progressive manner.
See this: http://developer.android.com/training/multiscreen/adaptui.html
Note that Fragments are supported only on devices running Android 3.0, so you might have to use Support Fragments (See: https://stackoverflow.com/a/6528757/713778)
But Again it depends on your specific needs. I am not sure what your exact use case is, but I would suggest you to watch some Android design in Action for some examples to improve your design and make your app "User Centric" (See: https://www.youtube.com/playlist?list=PLWz5rJ2EKKc8j2B95zGMb8muZvrIy-wcF)
I recently came across this https://www.youtube.com/playlist?list=PLWz5rJ2EKKc-riD21lnOjVYBqSkNII3_k seems provide an in-depth analysis on User Experience.
I would recommend using fragment for web like views. Fragments are pretty snappy compared to activities and reusable.
But before you start, make sure to fragments are good fit for your requirements since they are supported from android 3.0.
You can declare fragments from xml itself or you can create frame layout and add that view in the code itself.
http://www.c-sharpcorner.com/UploadFile/2fd686/fragments/
The above link has a good example tabhost.
As per Android design guidelines to support multiple screens(Phone and tablet),
In Tablet, we use single activity and load two fragments
In Phone, we use two activities A and B with master-detail fragments load in each activity.
In phone,why we need to start another activity B and put detail fragment on it? simply we can replace master-fragment by detail-fragment in Activity A itself?
That is certainly possible. It will make Activity A more complicated, though, and overall it may not simplify your app.
Indeed, Google now recommends using a single Activity.
Today we are introducing the Navigation component as a framework for
structuring your in-app UI, with a focus on making a single-Activity
app the preferred architecture.
For very long time, I think what is the reason of using fragment in Android if I just develop the application for Android Phone only but not 10.1.
Is it necessary to use fragment? Also, what is the usage of fragment,
I found that it may use for 'tab' and 'separate view'...
I really think it is very confusing. Can anyone explain briefly and give example?
From documentation
You can think of a fragment as a modular section of an activity, which
has its own lifecycle, receives its own input events, and which you
can add or remove while the activity is running (sort of like a "sub
activity" that you can reuse in different activities).
Some advantages are..
A particular UI part, once done in fragment, can be reused in
same/different activities.
You can separate different sections of UI, hence code will be neat,
and easy readable.
The ability of fragment to be able to reuse is very helpful when you are creating applications for different kind of android devices (phones, tablets). A well designed fragment can be just plugged into your UI hierarchy.
Fragments is a new concept introduced in 3.0 version.
The basic purpose of fragments is:
Fragments are designed to use the device UI space efficiently.
When you are writing an application in android, then some people can download it into phone, some into tablets. If you see the space in tablets it will be little bigger than phones. You should be able to use that space efficiently. But you can't keep writing different applications one targeting for phone, and other targeting for tablets. In order to do it efficiently, i.e writing only application that can fit well with all screen sizes, we use fragments concept.
fragments are designed as a reusable UI components between more than one activity.
Once you design a fragment, you can view it as a detachable independent unit, so that you can plug it into any activity where ever there is a space. That means you can reuse the code designed for a fragment.
Fragment you can think of it like a sub activity, which sits with in an activity and which contributes its own UI to the activity screen.
Fragments are always part of an activity. With out an activity, a fragment will not exist. So your fragment life cycle will always be affected by activity life cycle.
An activity can contain more than one fragment. Similarly a fragment can be re used in multiple activities.
If you use Fragment in your application, your apps will support all the device like small device, tablet and even google TV. In one .apk file, we will have different design for various devices.
This is the best Android tutorial that I've ever found. Section 21 covers fragments
Refer Here