Sunday, December 18, 2011

Example of using Compatibility Package, implement Fragment on pre-Android 3.0 devices

In this exercise, we will modify from the article "Programmatically add fragment", using Compatibility Package. To make it run on both Android 3.0 device and older version device.

on Nexus One running Android 2.3.6:
Fragment on Nexus One running Android 2.3.6

on HTC Flyer running Android 3.2.1:
Fragment on HTC Flyer running Android 3.2.1

- Create a new project with minSdkVersion="7" nd targetSdkVersion="11".
AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
 package="com.exercise.FragmentTest"
 android:versionCode="1"
 android:versionName="1.0" >

 <uses-sdk android:minSdkVersion="7" android:targetSdkVersion="11"/>

 <application
     android:icon="@drawable/ic_launcher"
     android:label="@string/app_name" >
     <activity
         android:name=".FragmentTestActivity"
         android:label="@string/app_name" >
         <intent-filter>
             <action android:name="android.intent.action.MAIN" />

             <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
     </activity>
 </application>

</manifest>


- Follow the last article to "Install and setup Compatibility Package" on your project.

- Create /res/layout/fragmentlayout.xml to define the layout of our fragment.
<?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="It's Fragment" />
<ImageView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:src="@drawable/ic_launcher"/>
</LinearLayout>


- Implement our Fragment class MyFragment.java extends Fragment.
package com.exercise.FragmentTest;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class MyFragment extends Fragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
  Bundle savedInstanceState) {
 // TODO Auto-generated method stub
 View myFragmentView = inflater.inflate(R.layout.fragmentlayout, container, false);
 return myFragmentView;
}

}


- Modify main.xml to add a FrameLayout, it will be added with our fragment.
<?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="horizontal" >

<TextView
    android:layout_width="0px"
    android:layout_weight="1"
    android:layout_height="match_parent"
    android:text="It's TextView in main Activity"
    android:background="#555555"/>
<FrameLayout
    android:id="@+id/myfragment"
    android:layout_width="0px"
    android:layout_weight="4"
    android:layout_height="match_parent">
</FrameLayout>

</LinearLayout>


- Modify main activity, FragmentTestActivity extends FragmentActivity, to add our fragment in the FrameLayout.
package com.exercise.FragmentTest;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;

public class FragmentTestActivity extends FragmentActivity {
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.main);
  
     // get an instance of FragmentTransaction from your Activity
     FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();

     //add a fragment
     MyFragment myFragment = new MyFragment();
     fragmentTransaction.add(R.id.myfragment, myFragment);
     fragmentTransaction.commit();
 }
}


*** Please take a notice on the import statements.

in FragmentTestActivity.java:
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;

in MyFragment.java
import android.support.v4.app.Fragment;

They are imported from android.support.v4.app, not android.app. Otherwise, your app can run on Android 3.0 or above, but fail in pre-3.0 device.

Download the files.

1 comment:

sohail aziz said...

Really great tutorial, thanks.