This ppt explains how

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.