Develop Reference

FragmentActivity inside a fragment

I am new to android and i have some questions. I created a simple layout with two fragments such as follow:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<FrameLayout
android:id="#+id/fragment1"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<FrameLayout
android:id="#+id/fragment2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true" />
I want to divide this layout as follow :
layout_height of fragment1 : 1/3 height
layout_height of fragment2 : 2/3 height
How can do it?
I used below code to show fragment1 :
FragmentTransaction transaction =
getSupportFragmentManager().beginTransaction();
transaction.add(R.id.fragment1, firstfragment);
But I don't know how to show FragmentActivity in fragment2 ?

You can achive this layout like this
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:weightSum="3"
>
<FrameLayout
android:id="#+id/fragment1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />
<FrameLayout
android:id="#+id/fragment2"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="2" />
</LinearLayout>
and in java you must call commit in transaction
//to add Fragment1
FragmentTransaction transaction =
getSupportFragmentManager().beginTransaction();
transaction.add(R.id.fragment1, firstfragment).commit();
// to add Fragment2
FragmentTransaction transaction1 =
getSupportFragmentManager().beginTransaction();
transaction1.add(R.id.fragment2, secondfragment).commit;
and you can not put any activity inside Fragments. but you can start another activity from your fragments

To put two elements in some ratio - use LinearLayout then set height of contained views to 0dp and add layoutWeight attributes in desired ratio (for example 1 and 2 in your case)
To instantiate fragments just use code as you written twice. You omitted the transaction.commit(); part. You have to cal this twice - once for every fragment you want to add.
Question about adding FragmentActivity is misleading - you can't put Activity into Fragment, you only can insert Fragment(s) into Activities.

Separate the layout to two activities, fragment

i want to separate my layout in two parts:
the bottom for ads, and the other part to the app(few activities).
why i want to do that? because i want the ad appears every time even when new activity started.
http://i.stack.imgur.com/plVeO.png
i realized that is possible to do that with fragment.
I have few questions about fragment:
fragment can hold two activities?
can i start a fragment like activity with intent?
The main question is how TO SEPARATE THE LAYOUT IN TO PARTS while using fragment?

No, fragment can not have two Activities, but vise versa - yes. For dynamic actions with fragments create xml file in which will 2 frames, one attached to the bottom, and read about http://developer.android.com/guide/components/fragments.html, http://developer.android.com/reference/android/app/FragmentManager.html, http://developer.android.com/reference/android/app/FragmentTransaction.html
Try this:
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<FrameLayout
android:id="#+id/frame1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1" >
</FrameLayout>
<FrameLayout
android:id="#+id/frame2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="3" >
</FrameLayout>
</LinearLayout>
in Activity:
NewFragment fragment = new NewFragment();
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.add(R.id.frame1, fragment);
ft.commit();
Or, static in xml:
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<fragment android:name="com.example.android.fragments.HeadlinesFragment"
android:id="#+id/headlines_fragment"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="match_parent" />
<fragment android:name="com.example.android.fragments.ArticleFragment"
android:id="#+id/article_fragment"
android:layout_weight="3"
android:layout_width="0dp"
android:layout_height="match_parent" />
</LinearLayout>

you could make one parent activity which will hold adverts and have free space for content, than you inherit that activity and fill up content from inherited one, maybe inflate other layouts in base. if you will be using more than one layout for content you could make also parent layout and "inherit" it as well.
or you can use one activity which would hold adverts and use fragments for content.

FragmenManager replace makes overlay

I'm using supportlib v4 to reach master-detail flow.
Problem:
New instance of "details" fragment overlays the first one (xml created) instead replace it.
My Activity layout is:
<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"
android:orientation="horizontal"
tools:context=".TrackListActivity" >
<fragment
android:id="#+id/fragmentList"
android:name="pl.com.digita.BikeComputerUi.TrackList.TrackListFragment"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1" />
<fragment
android:id="#+id/fragmentTrack"
android:name="pl.com.digita.BikeComputerUi.TrackList.TrackInfoFragment"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="2" />
</LinearLayout>
Method called after click:
private void showDetails(long trackId){
View fragmentContainer = getActivity().findViewById(R.id.fragmentTrack);
TrackInfoFragment trackInfoFragment = TrackInfoFragment.newInstance(trackId);
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(fragmentContainer.getId(), trackInfoFragment).commit();
}

Note: When you add a fragment to an activity layout by defining the fragment in the layout XML file, you cannot remove the fragment at runtime. If you plan to swap your fragments in and out during user interaction, you must add the fragment to the activity when the activity first starts, as shown in the next lesson.
Which is very last thing on http://developer.android.com/training/basics/fragments/creating.html

Here is solution - just need to change fragment to FrameLayout without loading it at activity creation:
<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"
android:orientation="horizontal"
tools:context=".TrackListActivity" >
<fragment
android:id="#+id/fragmentList"
android:name="pl.com.digita.BikeComputerUi.TrackList.TrackListFragment"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1" />
<FrameLayout
android:id="#+id/details"
android:layout_width="0px"
android:layout_height="match_parent"
android:layout_weight="2" />
</LinearLayout>

Check following code it will work.
View fragmentContainer = ClassName.this.findViewById(R.id.fragmentTrack);
TrackInfoFragment fragment = new TrackInfoFragment();
getSupportFragmentManager().beginTransaction()
.replace(fragmentContainer.getId(), fragment).commit();

How to change the "class" attribute of a Fragment from java code

In my android app, I have defined a fragment in my xml layout. The code is below:
<fragment
android:id="#+id/list_fragment"
android:layout_width="220dp"
android:layout_height="fill_parent"
android:layout_marginLeft="62dp"
android:layout_marginTop="20dp"
class="com.example.shantaportfolio.ListFragment" />
But I need to change the class attribute of the fragment from my java code. How can I do it? which method use?

You need to change <fragment/> by <FrameLayout/> in your .xml file
<fragment
android:id="#+id/list_fragment"
android:layout_width="220dp"
android:layout_height="fill_parent"
android:layout_marginLeft="62dp"
android:layout_marginTop="20dp"
/>
and then use java code to add fragment programatically
FragmentManager fragmentManager = getFragmentManager()
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
ListFragment fragment = new ListFragment();
fragmentTransaction.replace(R.id.list_fragment, fragment);
fragmentTransaction.commit();
you can get more details from
http://developer.android.com/guide/topics/fundamentals/fragments.html

If you just want to replace a Fragment implementation in the layout insert a "container element" into your layout and set the Fragment there:
in the layout:
<FrameLayout
android:id="#+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="0dp">
</FrameLayout>
In the code:
final FragmentTransaction tx = this.getFragmentManager().beginTransaction();
tx.replace(R.id.fragment_container, aFragment);
tx.commit();

You cannot intercept LayoutInflator instantiating the declared fragment. But You can replace() any fragment in your Activity with another afterwards.
Update:
You can use an Implementation of LayoutInflator.Factory, and use its onCreateView() method to do something different for some particular tags in layout.
You provide this factory implementation to LayoutInflator using setFactory()

You cannot alter Fragments which are declared in XML. Instead, declare a container where a fragment will belong and in the onCreate() method of your activity, attach a Fragment to this container. When you want to swap Fragments, simply use the replace method and specify which fragment you want to swap.Note: containers are usually made with a LinearLayout by arranging them to the specific size. Below is a simple XML layout which provides a layout on the left which is 2/3 the screen size and another on the right which is 1/3
<?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:baselineAligned="false"
android:orientation="horizontal" >
<LinearLayout
android:id="#+id/fragment_container_parent"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="2" />
<LinearLayout
android:id="#+id/fragment_container_child"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1" />
</LinearLayout>

Android programmatically add fragment - position in parent and layout

OK, I'm trying to create a universal app that shows 3 tabs in phone view and 3 columns in tablet landscape. As such I created several different XML layouts using Linear Layout.
However, using fragments, I came across a problem - I want to remove the leftmost column when a selection is made in that fragment. I believed I could do this but it turns out I can't remove fragments declared in XML. So now, I'm tring to create the middle and right columns in XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/menu_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<fragment
android:id="#+id/classification_fragment"
android:name="uk.colessoft.android.hilllist.fragments.MenuClassificationFragment"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
tools:layout="#layout/list_classifications" >
</fragment>
<fragment
android:id="#+id/map"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
class="com.google.android.gms.maps.SupportMapFragment" />
</LinearLayout>
Then add the first column using
FragmentManager fragmentManager = getSupportFragmentManager();
android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
MenuCountryFragment countryFragment=new MenuCountryFragment();
fragmentTransaction.add(R.id.menu_layout, countryFragment, "country_menu").commit();
but I have two problems:
a) The above code only puts the fragment at the right hand side of the Linear Layout and I can't specifiy position. It needs to be on the left.
b) XML gave me the freedom to define different weights for the fragment based on screen size/orientation. Setting layout parameters programmatically in the Fragments seems a backward step. I got round this by putting a placeholder view in the xml that I read the layout params from this and assign them in onCreateView but its a hack.
I know I can put the fragment in the correct place by adding it as a child of the first element in the xml but when I do this and remove the fragment it leaves a blank space.

Create a placeholder for the new fragment you want to add (in your XML), something like this...
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/menu_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<FrameLayout
android:id="#+android:id/realtabcontent"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1" />
<fragment
android:id="#+id/classification_fragment"
android:name="uk.colessoft.android.hilllist.fragments.MenuClassificationFragment"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
tools:layout="#layout/list_classifications" >
</fragment>
<fragment
android:id="#+id/map"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
class="com.google.android.gms.maps.SupportMapFragment" />
</LinearLayout>
Then, instead of adding a new fragment at runtime, replace the content of the empty container...
FragmentManager fragmentManager = getSupportFragmentManager();
android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
MenuCountryFragment countryFragment=new MenuCountryFragment();
fragmentTransaction.replace(R.id.realtabcontent, newFrag).commit();
fragmentManager.executePendingTransactions();
Hope this helps.