Android How to Use Intent (explicit) By Oum Saokosal Note: This tutorial is for ADT - Eclipse

1. 08. Intent (Explicit)
Oum Saokosal
Master of Engineering in Information Systems, South Korea
855-12-252-752
oum_saokosal@yahoo.com

2. Agenda
• What is Intent?
• Intent: Invoke another Activity explicitly
• Put Extra with Intent

3. What is Intent? (1)
• There are many uses of intent.
– You can use intents to invoke other applications
from your application.
– You can use intents to invoke internal or external
components from your application.
– You can use intents to raise events so that others
can respond in a manner similar to a publish-and
subscribe model.

4. What is Intent? (2)
• At the simplest level, an intent is an action that
you can tell Android to invoke. That is, you can
invoke activity 02 from activity 01.
• In order to invoke like that, you need to register
those activities in AndroidManifest.xml.
• See Example: IntentExplicit.

5. Intent: Invoke another Activity
explicitly

6. public class Activity01 extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main01);
}
public void gotoProfile(View v){
Intent in = new Intent(this, Activity02.class);
startActivity(in);
}
}

7. main01.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" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Name: Oum Saokosal" />
……
……
……
<Button
android:onClick="gotoProfile"
android:id="@+id/btnProfile"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Profile" />
</LinearLayout>

8. public class Activity02 extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main02);
}
public void backtoMain(View v){
Intent in = new Intent(this, Activity01.class);
startActivity(in);
}
}

9. main02.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Relationship: Engaged"
android:textAppearance="?android:attr/textAppearanceMedium" />
……
……
<Button
android:onClick="backtoMain"
android:id="@+id/btnBack"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Back"/>
</LinearLayout>

10. AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.kosalab" android:versionCode="1" android:versionName="1.0" >
<uses-sdk android:minSdkVersion="10" />
<application
android:icon="@drawable/ic_launcher"
android:label="Intent Explicit" >
<activity
android:label="Activity01"
android:name=".Activity01" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:label="Activity02" android:name=".Activity02"></activity>
</application>
</manifest>

11. Put Extra with Intent
• In PHP, you can send data from a file to
another file through session.
• Similar to that, you can send data from one
Activity to other one by putting extra with
Intent.
• The extra data is in the form of key/value
pairs.

12. putExtra() into Intent
public class Activity01 extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main01);
}
public void gotoProfile(View v){
Intent in = new Intent(this, Activity02.class);
in.putExtra("id", "4312");
startActivity(in);
}
}

13. getExtras() from getIntent
public class Activity02 extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main02);
Bundle extras = getIntent().getExtras();
if (extras != null) {
int id = 0;
if(extras.getString("id") != null){
id = Integer.parseInt(extras.getString("id"));
Toast.makeText(this,
"your id = " + id, Toast.LENGTH_LONG).show();
}
}
}
public void backtoMain(View v){
Intent in = new Intent(this, Activity01.class);
startActivity(in);
}
}

15. Go on to the next slide