Fragments represent reusable portions of user interface in an activity. An activity can host multiple fragments that the user can navigate between. Fragment transactions allow adding, replacing, and removing fragments within an activity. Fragments can communicate with each other using interfaces to pass data between fragments hosted by the same activity. [/SUMMARY]

1. Workshop India

2. » An activity is the equivalent of a Frame/Window in
GUI toolkits. It takes up the entire drawable area
of the screen (minus the status and title bars on
top).
» Activities are meant to display the UI and get input
from the user.
» Activities can be frozen when the focus is switched
away from them (eg: incoming phone call).
» Services on the other hand keep running for the
duration of the user’s ‘session’ on the device.

3. » Any screen state is called an activity.
» An Application always starts with a main activity
» An application can have multiple activities that the
user moves in and out of.
» A stack of activities is maintained by the android
system to handle back presses and returns.

4. » In res/layout we’ll need to make 2 xml files each
defining the layout for the individual activity.
˃ main.xml
˃ second.xml
» Each activity needs an activity class associated
with it, these are present in the /src folder
˃ mainActivity.java -> main.xml
˃ secondActivity.java -> second.xml

5. <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="I&apos;m screen 1 (main.xml)"
android:textAppearance="?android:attr/textAppearanceLarge" />
<Button
android:id="@+id/button1"
android:layout_width="fill_parent" Button that we’ll
android:layout_height="wrap_content" use to move to the
android:text="Click me to another screen" /> next activity
</LinearLayout>

6. <?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="I&apos;m screen 2 (second.xml)"
android:textAppearance="?android:attr/textAppearanceLarge" />
</LinearLayout>

7. package com.wingie;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class mainactivity extends Activity {
Button button;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

8. setContentView(R.layout.main);
addListenerOnButton();
}
public void addListenerOnButton() {
final Context context = this;
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent intent = new Intent(context, second.class);
startActivity(intent);
}
}); Then we create an
} intent to move to the
next activity,
} (Second.java)

10. <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.wingie"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="13"/>
<application android:label="@string/app_name">
<activity android:name=".main"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<activity This describes the
second activity in
android:label="@string/app_name"
the application
android:name=".second" >
</activity>
</application>
</manifest>

11. The super.fn() makes sure that the
overridden method is also called
before any of our code runs..
public class ExampleActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) { The activity is being created.
super.onCreate(savedInstanceState);
}
@Override
protected void onStart() { The activity is about to
become visible.
super.onStart();
}
@Override
protected void onResume() { The activity has become
visible (it is now "resumed").
super.onResume();
}

12. @Override
Another activity is taking
protected void onPause() {
focus (this activity is about
super.onPause(); to be "paused").
}
@Override
protected void onStop() {
super.onStop(); The activity is no longer
} visible (it is now "stopped")
@Override
protected void onDestroy() {
super.onDestroy();
The activity is about to be
} destroyed.
}

14. » A Fragment represents a behavior or a portion of
user interface in an Activity.
» A fragment must always be embedded in an
activity
˃ fragment's lifecycle is directly affected by the host activity's lifecycle.
» You can insert a fragment into your activity layout
˃ by declaring the fragment in the activity's layout file, as
a <fragment> element
˃ or from your application code by adding it to an existing ViewGroup
container.

15. » MainActivity.java
˃ Main Activity that will host the 2 fragments
˃ Layout : res/layout/Activity_main.xml
» Frag1.java
˃ Fragment 1 class
˃ Layout : res/layout/Frag1.xml
» Frag2.java
˃ Fragment 2 class.
˃ Layout: res/layout/frag2.xml

19. <LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<fragment
xmlns:android="http://schemas.android.com/apk/res/android"
android:name="com.example.fragtest.Frag1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="45"
android:id="@+id/frag1">
</fragment>

20. <fragment
xmlns:android="http://schemas.android.com/apk/res/an
droid"
android:name="com.example.fragtest.Frag2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="55"
android:id="@+id/frag2">
</fragment>
</LinearLayout>

21. <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="@+id/textview01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="Frag ONE"
tools:context=".MainActivity" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textview01"
android:text="ClickHere"
tools:context=".MainActivity" />
</RelativeLayout>

22. <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="@+id/textview02"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="Frag TWO"
tools:context=".MainActivity" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textview02"
android:text="Click---Here"
tools:context=".MainActivity" />
</RelativeLayout>

23. package com.example.fragtest;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}

24. package com.example.fragtest;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Frag1 extends Fragment {
public Frag1() {
// TODO Auto-generated constructor stub
}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle
savedInstanceState) {
View view = inflater.inflate(R.layout.frag1, container, false);
return view;
}
}

25. package com.example.fragtest;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Frag1 extends Fragment {
public Frag1() {
// TODO Auto-generated constructor stub
}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle
savedInstanceState) {
View view = inflater.inflate(R.layout.frag1, container, false);
return view;
}
}

26. » What are Fragments?
» What are Fragment Transactions?
» Message passing between two fragments.
˃ With example source code.