Develop Reference

How to replace parent fragment view with a child fragment's view?

I'm looking for some help in Android studio with replacing a parent fragment's view with the view of a child fragment when a view in the parent fragment is clicked. Thank you in advance for your help.
Right now I have a parent fragment which is a chat list, and a child fragment (the chat screen) that shows up when you click on an element of the chat screen (i.e. a button). The chat list looks like this:
<FrameLayout 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"
tools:context="com.example.myapplication.ChatListFragment">
<!-- Empty Container for Fragment to Live in -->
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ListView
android:id="#+id/chatListView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/moonstone">
</ListView>
</FrameLayout>
I have set the onClickListener for the chatListView as follows:
_chatListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
String chatName = _chatListAdapter.getItem(i).getChatTitle();
openChatScreen(chatName);
}
});
And the openChatScreenWindow() looks like this:
private void openChatScreen(String chatName)
{
_fragmentManager = getChildFragmentManager();
Log.i(CHAT_LIST_TAG, "starting chat screen fragment");
FragmentTransaction fragmentTransaction = _fragmentManager.beginTransaction();
ChatScreenFragment chatScreenFragment = ChatScreenFragment.newInstance(chatName);
fragmentTransaction.add(R.id.fragment_container, chatScreenFragment);
fragmentTransaction.addToBackStack(GlobalConstants.OPEN_CHAT_WINDOW_FRAGMENT_STRING + chatName);
fragmentTransaction.commit();
}
However, when I run this code, the child fragment is obscured, because both the frame layout (the view that the fragment is displayed in) and the chatListView have their widths and heights set to match_parent (I figured this out by testing the height and width of the chat list as 200dp, and I was able to see the child fragment behind it).
Is there a simple way to get the fragment to replace the chatListView whenever it is loaded?
For example, is there a way to change this view:
To this one:
... when an element in the chat list (the first one) is clicked?
I was thinking of changing the list view's visibility to invisible and visible based on whether the fragment is loaded, but that seems like a headache.
Please let me know what you think, thank you!

First off most modern way of managing fragments is - Navigation component
According your approach - you are adding child fragment on top of the prev fragment with fragmentTransaction.add, you can use fragmentTransaction.replace instead
Also, you might want to set child fragment background to solid color - to hide previous fragment, if you use this method - make child's fragment root clickable - to prevent fragments click through.
My recommendation - spend more time on learning Navigation component

How to create an overlay view within an activity

I have a requirement where i have an activity which shows list of items like facebook feeds and when clicking on a button from one of the list item a dialog has to popup which will show comments for that item.
I was going through the documentation and found out that we have to create a DialogFragment on the fly to achieve this. Please advice if this is the right approach.

You don't actually have to use a Dialog. I think dialogs are more appropriate when you want to show simple views or just an alert/confirmation to the user (normally done with an AlertDialog).
For your situation I guess the best approach would be to have a FrameLayout on your Activity, sibling of your main layout element, and add a Fragment to it when you want to show a popup like that over your main Activity's layout. As long as you put the fragment's view after your activity's root layout element, the fragment will be displayed on top of your main layout, as an overlay. e.g.:
<merge xmlns:android="http://schemas.android.com/apk/res/android">
<LinearLayout android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!-- Activity's main layout here -->
</LinearLayout>
<FrameLayout android:id="#+id/overlay_fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</merge>
and then on your Activity when you want to display the fragment you do:
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.add(R.id.overlay_fragment_container, yourFragment)
.commit();
Hope it helps :) Luck!

Add background image to individual fragments

I have an app with multiple fragments and I would like to know how to add a background that is different for each fragment. The layout I am using has scrollable tabs which all use the same xml file. I also have a MainActivity that sets the view and an adapter for each fragment. I know you can add a background using the xml file with android:background or something of the sort as well as setting it to the view in the main activity but I can't figure out how to do it to each tab. Thank you for any help!

To add background to fragment, you have to wrap it in some container
<LinearLayout
android:id="#+id/linearlayout01"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#ccc"
android:layout_weight="1"
android:orientation="vertical">
<fragment android:name="com.example.simplefragmentexample.LayOutOne"
android:id="#+id/frag_1"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</LinearLayout>
If you wish to use same xml file, you should set images programmatically
LinearLayout l = (LinearLayout) findViewById(R.id.linearlayout01);
l.setBackground(Image);
or use several xmls with android:background.

You can get the root View of the fragment with the Fragment getView() method. Then you can set the background of the View using one of the setBackground() methods of the View. For example to set a random background color to each fragment:
for ( Fragment f : fragments ) {
f.getView().setBackgroundColor ( (new Random()).nextInt() );
}
PS: I never used fragments, therefore my answer could be wrong.

Android fragments overlap previous view and button listeners

I have an activity A with a fragment A inside.
Activity A uses layout X, and fragment A uses layout A.
code of layout X:
<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"
tools:context=".MainActivity" >
<fragment
android:id="#+id/fragment1"
android:name="android.app.DialogFragment"
android:layout_width="wrap_content"
android:layout_height="500dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="113dp"
class="com.example.fragtester.FragA" />
</RelativeLayout>
Layout A is just textview + linearlayout.
I set up another fragment B that uses layout B.
Now that I use the following code in activity A to change the fragments:
Fragment f = new FragB();
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.fragment1, f);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
ft.addToBackStack(null);
ft.commit();
I end up having layout B displaying under layout A.
So I use a FrameLayout to wrap the fragment in layout X and use
ft.replace(R.id.FrameLayout1, f);
Now the view is working nicely. Though, another problem arises.
Although layout B covers layout A, but the buttons are still active.
That means when I am viewing layout B, I can still click buttons on layout A, even if I am not seeing it.
And even when I add fragment C/D/E..... (layouts C/D/E....), the buttons on layout A is still active.
Can anybody explain why is that? Am I using fragments wrongly? Thanks!
A way to get through is to make layout A blank, and use other layout to cover it. But it doesn't seems to be the "right" way??

Remove the fragment and add a FrameLayout
<FrameLayout
android:id="#+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ffffff" >
</FrameLayout>
then add fragments programmatically.
In android fragment button click pass through the fragments (i dont know if the fragments are suppose to work like that). what I used to do in such a situation is to make the layout of the fragment clickable. so the clicks wont pass through.

Instead of having fragment in your xml, try to create empty container for a fragments. For example empty frame layout. And then programmatically put your fragments in there.

Add the following attribute to the XML root layout of the fragment that goes on top.
android:clickable="true"
This will ensure that touch events will not propagate further than the top layer.

How to embed view of Fragment in the header of a ListFragment

I have a FragmentActivity where I'm dynamically adding Fragments in my onCreate. I want a Fragment above a ListFragment. Of course, the first thing I tried was the fragments in one LinearLayout in one ScrollView, but then the ListFragment would only show one row at a time.
I found Scrolling 2 fragment (one Fragment and one ListFragment) as one, but I don't know how to get the parent view of the Fragment to add to the header view of the ListFragment. I obviously get an NPE when call fragment.getView() and fragment.getView().getParent() because I'm still in the onCreate of my activity, so the views haven't been initialized yet.
How can I put a Fragment above a ListFragment?

Create a layout that contains your first fragment, like so:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<fragment
android:id="#+id/content"
android:name="your.fragment.YourFragment"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</FrameLayout>
And then, in your ListFragment, add this layout as a header, like so:
View header = inflater.inflate(R.layout.widget_user_fragment, null, false);
getListView().addHeaderView(header, null, true);