Fragments are very useful in modularizing the code and UI. Fragment's use increases reusability in the project.
In this tutorial:
1. How to use fragments with activity.
2. Getting click events in the activity from fragments.
3. Passing data from activity to fragments and fragments to fragments.
4. Replacing fragments from activity and from fragment to fragment.
Note:
Here we will create one activity MainActivity and 3 fragments MainFragment, InputFragment, DetailFragment.
We will take some input from user in one fragments and will show the entered values in another fragments.
Let's start:
1. Create a android project.
2. Create a MainActivity.
MainActivity.java
public class MainActivity extends FragmentActivity implements ActivityListener{
/** Called when the activity is first created.
* ActivityListener is the interface which is used
* to get callback from fragment.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//Fragments are added programmatically here...
MainFragment fragment = new MainFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.frameLayout, fragment);
transaction.commit();
}
public void getData(Bundle bundle) {
if ( bundle != null ) {
FragmentManager fragmentManager = getSupportFragmentManager();
DetailFragment detailFragment = new DetailFragment();
detailFragment.setArguments(bundle);
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.frameLayout, detailFragment);
transaction.commit();
}
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:id="@+id/frameLayout" >
</FrameLayout>
Note: To add fragments inside xml:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:id="@+id/frameLayout" >
<fragment
android:name="com.fragmentdemo.fragment.MainFragment" android:id="@+id/fragment" android:layout_weight="1" android:layout_width="0dp" android:layout_height="fill_parent" />
</FrameLayout>
3. Create MainFragment.
MainFragment.java
public class MainFragment extends Fragment{
private Button mInput;
/**
* Define Click listener for the button.
*/
private OnClickListener inputClickListener = new OnClickListener() {
public void onClick(View v) {
FragmentManager fragmentManager = getFragmentManager();
InputFragment inputFragment = new InputFragment();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.frameLayout, inputFragment);
transaction.addToBackStack(null);
transaction.commit();
}
};
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View contentView = inflater.inflate(R.layout.main_frag, null);
contentView.setDrawingCacheEnabled(false);
mInput = (Button)contentView.findViewById(R.id.btnInput);
return contentView;
}
@Override
public void onStart() {
super.onStart();
mInput.setOnClickListener(inputClickListener);
}
}
main_frag.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:orientation="vertical" >
<Button
android:id="@+id/btnInput"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Add User Details"
android:textSize="20dp" />
</LinearLayout>
4. Create InputFragment.
InputFragment.java
public class InputFragment extends Fragment{
private ActivityListener mListener;
private Button mSubmit;
private EditText mName, mOccupation, mDesignation;
private OnClickListener submitClickListener = new OnClickListener() {
public void onClick(View v) {
if (mName.getText().toString().trim().length() == 0|| mOccupation.getText().toString().trim().length() == 0 || mDesignation.getText().toString().trim().length() == 0 ) {
Toast.makeText( getActivity(), "Field can not be left empty.", Toast.LENGTH_SHORT).show();
}
else {
Bundle bundle = new Bundle();
bundle.putString("name", mName.getText().toString());
bundle.putString("occupation", mOccupation.getText().toString());
bundle.putString("designation", mDesignation.getText().toString());
//Method1: Pass data to activity and then to fragment.
if ( mListener != null )
mListener.getData(bundle);
//Method2: pass data to fragment directly.
FragmentManager fragmentManager = getFragmentManager();
DetailFragment detailFragment = new DetailFragment();
detailFragment.setArguments(bundle);
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.frameLayout, detailFragment);
transaction.remove(InputFragment.this);
transaction.commit();
}
}
};
//Check for interface if activity has implemented it or not.
@Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
try {
mListener = (ActivityListener)activity;
}catch (ClassCastException e) {
Toast.makeText( activity, "Activity must implement this interface.", Toast.LENGTH_SHORT).show();
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View contentView = inflater.inflate(R.layout.input_frag, null);
contentView.setDrawingCacheEnabled(false);
mSubmit = (Button)contentView.findViewById(R.id.btnSubmit);
mName = (EditText)contentView.findViewById(R.id.editName);
mOccupation = (EditText)contentView.findViewById(R.id.editOccupation);
mDesignation = (EditText)contentView.findViewById(R.id.editDesignation);
Bundle bundle = getArguments();
if ( bundle != null ) {
mName.setText(bundle.getString("name"));
mOccupation.setText(bundle.getString("occupation"));
mDesignation.setText(bundle.getString("designation"));
}
return contentView;
}
@Override
public void onStart() {
super.onStart();
mSubmit.setOnClickListener(submitClickListener);
}
//Define Interface for callback to activity.
public interface ActivityListener {
public void getData (Bundle bundle);
}
}
input_frag.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:padding="20dp" >
<TextView
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Name"
android:textSize="20dp" />
<EditText
android:id="@+id/editName"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="Enter your name"
android:textSize="20dp"
android:padding="10dp"
android:layout_marginTop="20dp" />
<TextView
android:id="@+id/occupation"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Occupation"
android:textSize="20dp"
android:layout_marginTop="20dp" />
<EditText
android:id="@+id/editOccupation"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="Enter your Occupation"
android:textSize="20dp"
android:padding="10dp"
android:layout_marginTop="20dp" />
<TextView
android:id="@+id/designation"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Designation"
android:textSize="20dp"
android:layout_marginTop="20dp" />
<EditText
android:id="@+id/editDesignation"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:hint="Enter your Designation"
android:textSize="20dp"
android:padding="10dp"
android:layout_marginTop="20dp" />
<Button
android:id="@+id/btnSubmit"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Submit"
android:textSize="20dp"
android:layout_marginTop="20dp" />
</LinearLayout>
5. Create DetailFragment.
DetailFragment.java
public class DetailFragment extends Fragment{
private TextView mInfo;
private Button mEditDetail, mClose;
private Bundle mBundleData;
private OnClickListener editClickListener = new OnClickListener() {
public void onClick(View v) {
InputFragment inputFragment = new InputFragment();
inputFragment.setArguments(mBundleData);
getFragmentManager().beginTransaction().
replace(R.id.frameLayout, inputFragment).addToBackStack(null).commit();
}
};
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View contentView = inflater.inflate(R.layout.detail_frag, null);
contentView.setDrawingCacheEnabled(false);
mInfo = (TextView)contentView.findViewById(R.id.detail);
mEditDetail = (Button)contentView.findViewById(R.id.btnEdit);
mBundleData = getArguments();
if ( mBundleData != null ) {
mInfo.setText("Name: " + mBundleData.getString("name") + "\n"
+ "Occupation: " + mBundleData.getString("occupation") + "\n"
+ "Designation: " + mBundleData.getString("designation") + "\n" );
}
return contentView;
}
@Override
public void onStart() {
super.onStart();
mEditDetail.setOnClickListener(editClickListener);
}
}
detail_frag.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:gravity="center" >
<TextView
android:id="@+id/detail"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20dp" />
<Button
android:id="@+id/btnEdit"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Edit User Details"
android:textSize="20dp" />
</LinearLayout>
Source:
