The up navigation in action bar facilitates users to traverse from one activity to another activity in a specific hierarchical order. This is especially useful when the activity is opened from another application. In this article we will see how to enable and implement up navigation in action bar.
If you want you to enable up navigation in pre Honeycomb ( API Level < 3.0 ) versions, see the article titled “Hierarchical up navigation in pre Honeycomb versions using Sherlock library“.
This application is developed in Eclipse 3.7.2 and tested in Android virtual device of API level 14.
1. Create a new Android application namely “ActionBarUpNav”
Figure 1 : Create new Android Application
2. Select build target for this application
Figure 2 : Select Android Build Target
3. Enter application details
Figure 3 : Enter application Details
4. res/values/strings.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, MainActivity!</string>
<string name="app_name">ActionBarUpNav</string>
<string name="second">Second Activity</string>
<string name="txt_btn">Open Second Activity</string>
</resources>
5. Create a new layout file called “second_layout.xml” in the folder res/layout
<?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/tv_lbl"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/second"
/>
</LinearLayout>
6. Create a class namely “SecondActivity” in the folder src/in/wptrafficanalyzer/actionbarupnav
package in.wptrafficanalyzer.actionbarupnav;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.MenuItem;
public class SecondActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getActionBar().setDisplayHomeAsUpEnabled(true);
setContentView(R.layout.second_layout);
}
/** The event listener for the Up navigation selection */
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId()){
case android.R.id.home:
Intent intent = new Intent(this,MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
}
return true;
}
}
- The highlighted code enables the Up navigation for the activity
7. Update res/layout/main.xml to include a button, which opens the SecondActivity
<?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" >
<Button
android:id="@+id/btn"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/txt_btn" />
</LinearLayout>
8. Update MainActivity class ( src/in/wptrafficanalyzer/actionbarupnav/MainActivitiy.java) to define button click listener which opens the SecondActivity
package in.wptrafficanalyzer.actionbarupnav;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
OnClickListener listener = new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent("in.wptrafficanalyzer.actionbarupnav.second");
startActivity(intent);
}
};
Button btn = (Button) findViewById(R.id.btn);
btn.setOnClickListener(listener);
}
}
9. Update AndroidManifest.xml to include SecondActivity to this application
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="in.wptrafficanalyzer.actionbarupnav"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="14" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".MainActivity"
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
android:name=".SecondActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="in.wptrafficanalyzer.actionbarupnav.second" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
10. Execute the application
Figure 4 : Action Bar with Up navigation enabled
- On clicking the application icon, the current screen would be navigated to MainActivity screen.
11. Download
12. Reference
http://developer.android.com/guide/index.html
I am George Mathew, working as software architect and Android app developer at wptrafficanalyzer.in
You can hire me on hourly basis or on project basis for Android applications development.
For hiring me, please mail your requirements to info@wptrafficanalyzer.in.
My other blogs
store4js.blogspot.com
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Hi in this example the previous activity will start from onCreate(),may i know how to avoid this