How to get the current fragment in Android - code examples included

To get the current fragment that’s active in your Android Activity class, you need to use the supportFragmentManager object.

The supportFragmentManager has findFragmentById() and findFragmentByTag() methods that you can use to get a fragment instance.

For example, suppose you have a Fragment class named FirstFragment created in your activity as shown below:

val fragmentTransaction = supportFragmentManager.beginTransaction()

fragmentTransaction.replace(R.id.frameLayout, FirstFragment())

fragmentTransaction.commit()

In the above example, the FirstFragment is inflated in a <FrameLayout> that has an id value of frameLayout.

You can get the Fragment instance inflated inside the frameLayout using the supportFragmentManager like this:

supportFragmentManager.findFragmentById(R.id.frameLayout)

In the following example, a click listener was set on the activity button myBtn.

When the button is clicked, Android will try to find a fragment by the id value.

Then, check the instance type by using the Kotlin is operator:

myBtn.setOnClickListener {
    val fragmentInstance = supportFragmentManager.findFragmentById(R.id.frameLayout)

    if(fragmentInstance is FirstFragment){
        Toast.makeText(this, "FirstFragment found", Toast.LENGTH_SHORT).show()
    } else {
        Toast.makeText(this, "Not found", Toast.LENGTH_SHORT).show()
    }
}

When the fragmentInstance is an instance of the FirstFragment class, the if statement will evaluate to true.

Alternatively, you can also get a fragment by the tag you set in the replace() method of the fragmentTransaction instance:

// Set a tag after the fragment class:

fragmentTransaction.replace(R.id.frameLayout, FirstFragment(), "FF1")

The tag FF1 defined above allows you to retrieve the fragment using the FragmentManager.findFragmentByTag() method:

val fragmentInstance = supportFragmentManager.findFragmentByTag("FF1")

Once you get the current fragment by its tag, you can use the is operator again to check the fragment’s instance type.

Get the current fragment using Java

When you’re developing an Android application with Java, you can get the current fragment instance using the FragmentManager class.

You need to find the fragment by the id of the <FragmentContainerView> or the <FrameLayout> tag you used as the container of your fragment.

For example, suppose you placed a Fragment class named FirstFragment in your <FragmentContainerView> as shown below:

<androidx.fragment.app.FragmentContainerView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/fragment_container_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:name="org.metapx.FirstFragment" />

You can get the FirstFragment instance programmatically with Java in your Activity class code.

First, get the FragmentManager instance by calling the getSupportFragmentManager() method:

FragmentManager fm =  getSupportFragmentManager();

Using the fm instance, call the findFragmentById() method and pass the view id value as its argument.

In this example, the id value is fragment_container_view:

Fragment fragInstance = fm.findFragmentById(R.id.fragment_container_view);

The last thing you need to do is check the fragInstance if it’s an instance of the FirstFragment as shown below:

if (fragInstance instanceof FirstFragment){
    Toast.makeText(
        MainActivity.this, 
        "FirstFragment found", 
        Toast.LENGTH_SHORT
    ).show();
}

By using the instanceof operator, you can check if the fragInstance you retrieved is an instance of a specific class.

And that’s how you can get the current fragment in an Android application, both in Kotlin and in Java.

Feel free to copy and adjust the code in this tutorial for your Android application. 😉