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. This lesson shows how to extend the Fragment class using the Support Library so your app remains compatible with devices running system versions as low as Android 1.
Instead of setting up your dependent components in the lifecycle methods of your Fragment you should create a lifecycle-aware component instead.
The component can handle any setup or tear down that is required as your Fragment moves through its lifecycle. Before you begin this lesson, you must set up your Android project to use the Support Library.
If you have not used the Support Library before, set up your project to use the v4 library by following the Support Library Setup document. However, you can also include the app bar in your activities by instead using the v7 appcompat library, which is compatible with Android 2. For more information about implementing fragments, see Fragments.
You can also learn more by exploring the relevant sample app. To create a fragment, extend the Fragment class, then override key lifecycle methods to insert your app logic, similar to the way you would with an Activity class. One difference when creating a Fragment is that you must use the onCreateView callback to define the layout. In fact, this is the only callback you need in order to get a fragment running.
For example, here's a simple fragment that specifies its own layout:. Just like an activity, a fragment should implement other lifecycle callbacks that allow you to manage its state as it is added or removed from the activity and as the activity transitions between its lifecycle states.
For instance, when the activity's onPause method is called, any fragments in the activity also receive a call to onPause. More information about the fragment lifecycle and callback methods is available in the Fragments developer guide. While fragments are reusable, modular UI components, each instance of a Fragment class must be associated with a parent FragmentActivity. You can achieve this association by defining each fragment within your activity layout XML file.
Note: FragmentActivity is a special activity provided in the Support Library to handle fragments on system versions older than API level If the lowest system version you support is API level 11 or higher, then you can use a regular Activity. Here is an example layout file that adds two fragments to an activity when the device screen is considered "large" specified by the large qualifier in the directory name.
Tip: For more about creating layouts for different screen sizes, read Supporting Different Screen Sizes. If you're using the v7 appcompat libraryyour activity should instead extend AppCompatActivitywhich is a subclass of FragmentActivity.
For more information, read Adding the App Bar. Note: When you add a fragment to an activity layout by defining the fragment in the layout XML file, you cannot remove the fragment at runtime. If you plan to swap your fragments in and out during user interaction, you must add the fragment to the activity when the activity first starts, as shown in Build a flexible UI.
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Android Fragments with Examples
App Basics. Build your first app. App resources. Resource types. App manifest file. App permissions.You may have noticed one thing while using the android app of WhatsApp that they have slider tabs on the main page. When you slide horizontally among these three tabs, every tab have different layout but they are not opening in new activity.
Instead, all three are changing inside specific and static rectangle place only. Here, they have used fragments for layout of these three tabs. A fragment must be hosted by any activity. For example, when the activity is paused, so are all fragments in it, and when the activity is destroyed, so are all fragments. However, you change the state of any fragment such as add or remove when the activity is in running mode.
Android also provides the feature to add the fragment to the backstack similar to that the backstack of activity. Main aim for this is to support more dynamic and flexible UI designs on large screens, such as tablets.
In the larger screen of the tablet, there is much more space to combine and interchange the UI components effectively. This is where fragments help us to create such type of designs without handling the complex view hierarchy. At the right side, another fragment will show whole article in depth.
These both fragments are in the same activity.
Understanding Android Fragments with Example
Take a look at the below image Image credit goes here. Now for the same application, consider the screen of mobile device. It is relatively small compare to the tablet. So in this case, we can create two activities. First activity will hold the first fragments with the lists of the articles. When the user clicks on any article from the list, we will open another activity with second fragment which will show up the whole article.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I am trying to set the values for my spinner from a string Array in one of my fragments in the onCreateView in my public final class Manual extends Fragment :. I get no errors with my code, however it doesn't set the spinner. The spinner remains blank with no values. Any ideas on why my code isn't setting the spinner?
The problem was I was returning a new view, not the one I set. I had to return v; and it worked fine. Learn more.
Setting spinners in fragment Ask Question. Asked 7 years, 7 months ago. Active 3 years, 11 months ago. Viewed 44k times. Nick Nick 8, 30 30 gold badges 87 87 silver badges bronze badges. Active Oldest Votes. I literally just made the same mistake as you, thanks for posting this. I have took one day to figure out the v. Sign up or log in Sign up using Google. Sign up using Facebook.
Different device screen size are also different. So when you create an android app, of course you want it can be run in both small size android phone and big size android pad devices use only one release build. For small size android device android phonethere are not so many spaces, so it will use only one panel to display content for different view title view, content vieweach view can be implemented by one activity.
But for big size android devices, the screen size is big, both title list and the detail content can be displayed in one panel only use one activity. How can we make the app to adapt both small size and big size android devices use only one activity? We can use android Fragments to implement this. Fragment is something like Frame in Html.
One Html can contains multiple Frames, and one Activity can includes multiple Fragments. It can be reused by any activity. Because Fragment depends on Activity. So Fragment life cycle is similar to Activity life cycle. Below diagram illustrates the relationship between activity and fragment life cycle. We will introduce Fragment life cycle methods in another article later.
Because we will demo how to show multiple Fragments in one activity, so we need to use an android Tablet emulator. Below is the steps to create android Tablet emulator in android studio.
This example includes two Fragments. It contains three buttons. It contains one TextView. Really nice…. How can i do it.?? Your email address will not be published. This site uses Akismet to reduce spam. Learn how your comment data is processed. Skip to content. Leave a Reply Cancel reply Your email address will not be published.Fragments will help to create this dynamic user interfaces somehow.
In example, if you used WhatsApp or Facebook, you may see that you can slide the screen interface, but it's not opening any new activity. Just passing new UI in the same activity. Those are the real example of Fragment. Today through out this tutorial I'll try to make the concept of Fragment clear to you.
Create a new Android Studio project. For this tutorial, I used the name of the project " Fragments Tutorial ". You can follow my previous tutorial on Getting started with Android and Kotlin. Let me clear more.
But it runs under your activity, it is displayed from an Activity. If you know Biology, and are aware of the concept of Host and Parasitethen in Android, Activity is the host while a Fragment is a parasite.
To do so, the activity need not to be reloaded or refreshed, switching fragments is done on runtime. Also, a fragment is a re-usable component, hence, a single fragment can be included in multiple activities, if required. As like the above diagram on "What is Android Fragment" section, today we'll create two fragments with their own layout and display them in same activity. So first, lets create our First Fragment.
As like onCreate method in Activity, we have onViewCreated here. As we initialize our views in onCreate method, here we can do the same things. It is just to show you, how can you perform normal tasks as like in Activity. Before showing you how to display fragment in Activity, I want to have clear understanding on View and ViewGroup. The reason I'm repeating all these is, fragment class has it's own individual layout. The layout can contain different views and viewgroups.
So if we want to display the fragment inside an Activity, we'll need a ViewGroup in our layout resource file of our activity. And the Buttons will be used to switch which fragment to be displayed without reloading the Activity.
At first, we've initialized a Support Fragment Manager that will help us on fragment related activities.In android, Fragments are the modular section of activity design and these are used to represent the behavior of user interface UI in an activity. By using fragments we can create flexible UI designs that can be adjusted based on the device screen size such as tablets, smartphones.
We can build multi-pane UI by combining multiple fragments in a single activity and we can reuse the same fragment in multiple activities. The fragment has its own lifecycle call-backs and accepts its own input events. We can also implement a fragment without having any user interface UI.
Following is the example of defining a multiple fragments in single activity for the tablet design to display the details of an item which we selected in the app, but separated for mobile design. If you observe above example for Tablet we defined an Activity A with two fragments such as one is to show the list of items and second one is to show the details of item which we selected in first fragment.
For Handset device, there is no enough space to show both the fragments in single activity, so the Activity A includes first fragment to show the list of items and the Activity B which includes another fragment to display the details of an item which is selected in Activity A. Following is a pictorial representation of the android fragment life cycle while its activity is running. Following are the list of methods which will perform during the lifecycle of fragment in android applications.
Following is the example of creating a two fragments, two buttons and showing the respective fragment when click on button in android application.
Create a new android application using android studio and give names as Fragments. In case if you are not aware of creating an app in android studio check this article Android Hello World App. Now we need to create our own custom fragment class files ListMenuFragment.
Once we create a new file DetailsFragment. Fragment; import android. Bundle; import android. LayoutInflater; import android. View; import android. ViewGroup; import android. If you observe above code we extended class with Fragment and used LayoutInflater to show the details of fragment.
We defined a function change to change the text in textview. Same way create another file ListMenuFragment. ListFragment; import android. ArrayAdapter; import android.
If you observe above code we extended our class using ListFragment and we defined two array of strings users, location which contains names and locations. We defined onListItemClick event to update the name and location in DetailsFragment based on the list item which we clicked. We are not going to make any modifications for our main activity file MainActivity. When we execute the above example in the android emulator we will get a result like as shown below.
Android Fragments with Examples. Method Description onAttach It is called when the fragment has been associated with an activity. Android Fragments Examples Following is the example of creating a two fragments, two buttons and showing the respective fragment when click on button in android application. It is called when the fragment activity has been created and the fragment view hierarchy instantiated.A fragment is a reusable class implementing a portion of an activity.
A Fragment typically defines a part of a user interface.Tab Layout with Different Fragments - Android Studio Tutorial
Fragments must be embedded in activities; they cannot run independently of activities. Within a fragment-oriented architecture, activities become navigational containers that are primarily responsible for navigation to other activities, presenting fragments and passing data.
Within a fragment-heavy app, we need to remember to organize our code according to architectural best practices. Inside of an app which uses fragments extensively, we need to keep in mind that the role of an activity shifts.
Fragments are content controllers and contain most views, layouts, and event logic including:. To reiterate, in a fragment-based architecture, the activities are for navigation and the fragments are for views and logic. A fragment, like an activity, has an XML layout file and a Java class that represents the Fragment controller. Think of them as a partial re-usable activity:. There are two ways to add a fragment to an activity: dynamically using Java and statically using XML.
Before embedding a "support" fragment in an Activity make sure the Activity is changed to extend from FragmentActivity or AppCompatActivity which adds support for the fragment manager to all Android versions. Any activity using fragments should make sure to extend from FragmentActivity or AppCompatActivity :. To add the fragment staticallysimply embed the fragment in the activity's xml layout file:.
The second way is by adding the fragment dynamically in Java using the FragmentManager. The FragmentManager class and the FragmentTransaction class allow you to add, remove and replace fragments in the layout of your activity at runtime. In this case, you want to add a "placeholder" container usually a FrameLayout to your activity where the fragment is inserted at runtime:.
If the fragment should always be within the activity, use XML to statically add the fragment but in more complex cases be sure to use the Java-based approach.
Fragment has many methods which can be overridden to plug into the lifecycle similar to an Activity :. The most common ones to override are onCreateView which is in almost every fragment to setup the inflated view, onCreate for any data initialization and onActivityCreated used for setting up things that can only take place once the Activity has been fully created. Refer to this detailed lifecycle chart to view the lifecycle of a fragment more visually.
Often we need to lookup or find a fragment instance within an activity layout file. There are a few methods for looking up an existing fragment instance:. If the fragment was statically embedded in the XML within an activity and given an android:id such as fragmentDemo then we can lookup this fragment by id by calling findFragmentById on the FragmentManager :.
If the fragment was dynamically added at runtime within an activity then we can lookup this fragment by tag by calling findFragmentByTag on the FragmentManager :. If the fragment was dynamically added at runtime within an activity into a ViewPager using a FragmentPagerAdapter then we can lookup the fragment by upgrading to a SmartFragmentStatePagerAdapter as described in the ViewPager guide.
Now with the adapter in place, we can also easily access any fragments within the ViewPager using getRegisteredFragment :. Note that the ViewPager loads the fragment instances lazily similar to the a ListView recycling items as they appear on screen. If you attempt to access a fragment that is not on screen, the lookup will return null. Fragments should generally only communicate with their direct parent activity. Fragments communicate through their parent activity allowing the activity to manage the inputs and outputs of data from that fragment coordinating with other fragments or activities.
Think of the Activity as the controller managing all interaction with each of the fragments contained within. A few exceptions to this are dialog fragments presented from within another fragment or nested child fragments. Both of these cases are situations where a fragment has nested child fragments and that are therefore allowed to communicate upward to their parent which is a fragment.