Prerequisites:
In Android, a fragment is a portion of the user interface that can be used again and again. Fragment manages its own layout and has its own life cycle. Since fragment is a small portion of the bigger user interface, it can only be initialized inside an activity or another fragment. So if we wish to display any type of resources, such as a string, or an image inside the fragment, we will need to declare them in the activity and then pass it to the fragment. So in this article, we will show you how you can pass data from an Activity to the Fragment.
Step by Step Implementation
Step 1: Create a New Project in Android Studio
To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. We demonstrated the application in Kotlin, so make sure you select Kotlin as the primary language while creating a New Project.
Step 2: Create a custom fragment layout (my_custom_fragment.xml) in the layout folder
We shall pass a string to the fragment. To display this string, we implemented a TextView.
<? xml version = "1.0" encoding = "utf-8" ?>
< LinearLayout
android:layout_width = "match_parent"
android:layout_height = "wrap_content"
android:orientation = "vertical" >
<!-- TextVIew to display the passed text -->
< TextView
android:id = "@+id/fragmentTextView"
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:layout_gravity = "center"
android:textColor = "@color/white"
android:textSize = "50sp"
android:background = "#0f9d58" />
</ LinearLayout >
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Step 3: Add EditText, Button, and Frame in the layout file (activity_main.xml)
Refer to the comments inside the code for better understanding.
<? xml version = "1.0" encoding = "utf-8" ?>
< RelativeLayout
android:layout_width = "match_parent"
android:layout_height = "match_parent"
tools:context = ".MainActivity" >
<!-- We will type text in this EditText -->
< EditText
android:id = "@+id/editText"
android:layout_width = "match_parent"
android:layout_height = "50sp" />
<!-- Click this button to pass text
in EditText to the Fragment -->
< Button
android:id = "@+id/button"
android:layout_below = "@+id/editText"
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:layout_centerHorizontal = "true"
android:text = "Pass" />
<!-- Text will be displayed in a
TextView in this Fragment -->
< FrameLayout
android:id = "@+id/frameLayout"
android:layout_below = "@+id/button"
android:layout_width = "match_parent"
android:layout_height = "match_parent" />
</ RelativeLayout >
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Step 4: Create a class for the custom fragment (MyCustomFragment.kt)
This is a custom fragment class to inflate the custom layout in the frame layout present in the main activity.
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
class MyCustomFragment: Fragment() {
// Declaring TextView from the custom fragment layout
private lateinit var myTextView: TextView
// Override function when the view is being created
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
// Inflates the custom fragment layout
val view: View = inflater.inflate(R.layout.my_custom_fragment, container, false )
// Finds the TextView in the custom fragment
myTextView = view.findViewById<View>(R.id.fragmentTextView) as TextView
// Gets the data from the passed bundle
val bundle = arguments
val message = bundle!!.getString( "mText" )
// Sets the derived data (type String) in the TextView
myTextView.text = message
return view
}
} |
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.fragment.app.Fragment;
public class MyCustomFragment extends Fragment {
// Declaring TextView from the custom fragment layout
private TextView myTextView;
// Override function when the view is being created
@Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container,
Bundle savedInstanceState)
{
// Inflates the custom fragment layout
View view = inflater.inflate(
R.layout.my_custom_fragment, container, false );
// Finds the TextView in the custom fragment
myTextView = (TextView)view.findViewById(
R.id.fragmentTextView);
// Gets the data from the passed bundle
Bundle bundle = getArguments();
String message = bundle.getString( "mText" );
// Sets the derived data (type String) in the
// TextView
myTextView.setText(message);
return view;
}
} |
Step 5: Initialize MyCustomFragment class and pass the values from the EditText (MainActivity.kt)
In this program, the EditText value (input string) is fetched on a button click. The custom fragment class is initialized and the input string is passed to get desired results. Please refer to the comments inside the code below for a better understanding.
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.EditText
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super .onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// Declaring and initializing the EditText and Button from the layout
val mEditText = findViewById<EditText>(R.id.editText)
val mButton = findViewById<Button>(R.id.button)
// Declaring fragment manager from making data
// transactions using the custom fragment
val mFragmentManager = supportFragmentManager
val mFragmentTransaction = mFragmentManager.beginTransaction()
val mFragment = MyCustomFragment()
// On button click, a bundle is initialized and the
// text from the EditText is passed in the custom
// fragment using this bundle
mButton.setOnClickListener {
val mBundle = Bundle()
mBundle.putString( "mText" ,mEditText.text.toString())
mFragment.arguments = mBundle
mFragmentTransaction.add(R.id.frameLayout, mFragment).commit()
}
}
} |
import android.os.Bundle;
import android.widget.Button;
import android.widget.EditText;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState)
{
super .onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Declaring and initializing the EditText and
// Button from the layout
final EditText mEditText
= findViewById(R.id.editText);
final Button mButton = findViewById(R.id.button);
// Declaring fragment manager from making data
// transactions using the custom fragment
final androidx.fragment.app
.FragmentManager mFragmentManager
= getSupportFragmentManager();
final androidx.fragment.app
.FragmentTransaction mFragmentTransaction
= mFragmentManager.beginTransaction();
final MyCustomFragment mFragment
= new MyCustomFragment();
// On button click, a bundle is initialized and the
// text from the EditText is passed in the custom
// fragment using this bundle
mButton.setOnClickListener(
new View.OnClickListener() {
@Override public void onClick(View v)
{
Bundle mBundle = new Bundle();
mBundle.putString(
"mText" ,
mEditText.getText().toString());
mFragment.setArguments(mBundle);
mFragmentTransaction
.add(R.id.frameLayout, mFragment)
.commit();
}
});
}
} |
Output:
We can see that when the text is typed in the EditText and the button is clicked, the same text is displayed in our custom fragment.