Develop Reference

How do we initialize views created at runtime inside a LinearLayout from a Fragment?

I have a fragment with an empty LinearLayout. At some point a user will click an "Add" button that will trigger the appearance of another LinearLayout inside the first one:
// inside the onClick method...
case R.id.addPlayerButton: addItemsToLinearLayout(mContext, 1);
I have the inner LinearLayout on a different xml file and it contains several views. One of these views is a delete icon whose function is to delete the row, that is, delete the inner LinearLayout.
My problem is that I get a NullPointerException when I try to initialize the delete icon, which is an ImageView in the following way from the onCreateView of the fragment:
//class field private ImageView deleteRowIcon;
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_choose_players, container, false);
deleteRowIcon = view.findViewById(R.id.deleteRowIcon);
return view;
}
I've read the documentation on findViewById of the class View and it says that it returns null if it doesn't find any view with that id, but then, why am I able to even write view.findViewById(R.id.deleteRowIcon) without getting a warning telling me this is not possible? IntelliJ even gives it to me as an option to choose from!

Change a TextView Visibility in Fragment

I have a some fragment in my PageViewer.
In the main fragment, I would like to show a component ( TextView or imageView) if there is no connection.
In the code below, I can reach my textview, but I cannot get them disapperead.
public class MainFragment extends Fragment {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View layout = inflater.inflate(R.layout.main, container, false);
// RelativeLayout mainLayout = (RelativeLayout)findViewById(R.layout.main);
TextView TxtIsNotConnected = (TextView) layout.findViewById(R.id.isNotConnected);
TextView TxtIsConnected = (TextView) layout.findViewById(R.id.isConnected);
// String text = TxtIsNotConnected.getText().toString(); // This is a test which works, return the text o my textview.
boolean isConnected = ConnectivityUtils.isConnected(getActivity()); // This Works fine
if (!isConnected) TxtIsNotConnected.setVisibility(View.VISIBLE); // NOT WORKING
else TxtIsConnected.setVisibility(View.VISIBLE); // NOT WORKING
return inflater.inflate(R.layout.main, container, false);
}
How should I do???

To make your TextView visible
yourTextView.setVisibility(View.VISIBLE);
To make Invisible
yourTextView.setVisibility(View.GONE);
From your code it seems that you have to keep one view visible and another invisible. So, please try this
if (!isConnected) {
TxtIsNotConnected.setVisibility(View.VISIBLE);
TxtIsConnected.setVisibility(View.GONE);
} else {
TxtIsConnected.setVisibility(View.VISIBLE);
TxtIsNotConnected.setVisibility(View.GONE);
}
Hope it helps...
Edit :
Well, your code is correct about visibility but you have made a silly mistake that's why it seems that your code is not working. Look at the first line and last line of your onCreateView method. You have inflated your R.layout.main in View object called "layout". You have set your actions within that layout. Finally you have returned a new instance of that view. So, your previous codes became useless. So, your return statement will be...
return layout ;
It should fix the problem.

Customize a xml layout in a fragment - Android

I am new in Android programming.
I created the main Activity of my app style google shop ussing ActionBarSherlock and a NavigationTabs, with fragments, each referencing another activity (Fragment 1 Fragment 2, etc) and each fragment inflating a layout.
However, I'm used to create layouts in xml and then customize them in java. To put a different text depending on the time of day, or according to some data in a database, giving function to buttons, etc.. But in a Fragment Class, I can not even use setContentView to work with each text or button, and set the context for using my database is giving me problems.
How I can customize a xml layout in a fragment?
Or what would be the right thing to do?
Here my Fragment:
public class Fragment1 extends SherlockFragment{
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
return inflater.inflate(R.layout.menu, container, false);
}

This is more simple then you think. onCreateView instanciate au returns the view for your Fragment. As you said, in a simple Activity you set (and instanciate) the view with setContentView() and then you get your Views with findViewById().
findViewById() asks for the view to return the view item that you want, you can call it from your view before returning it. Like this:
public class Fragment1 extends SherlockFragment{
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View v = inflater.inflate(R.layout.menu, container, false);
// For example, getting a TextView
TextView tv = (TextView) v.findViewById(R.id.myTextView);
// do your job
return v;
}

so far so good, you just need to use the view you are inflating to get everything.
here is an example
View v = inflater.inflate(R.layout.menu, container, false);
Button b = (Button)v.findViewById(r.id.button1);
return v;

inside onActivityCreated you could use:
View mView = getView();
TextView textView = (TextView) view.findViewById(R.id.theIdOfTextView);
where theIdOfTextView is declared inside R.layout.menu.
getView() returns the View you inflated inside onCreateView. You use it only after onCreateView has been executed

why we access like that getActivity().findViewById()

When a layout , which is defined for a Fragment and used inside setContentView() method and it has no relation with Activity .
then why we need Activity Reference to access it .
so I want to create a ListView , inside a Fragment . than i have to create it inside Activity layout or inside Fragment layout .
Hey Neil , i have a question because every time I have made a mistake because , i am performing this
TextView txt = ( TextView ) getActivity().findViewById(R.id.txt);
txt.setText("nayak nahi , khalnayak hun mein");
inside oncreateView() so it is creating problem but when ever i am implementing this inside
onActivityCreated() , it is working , so can you please tell me Why this is happening .

if you want to find the view by getActivity(), you should do that after onCreateView is called, because till onCreateView is called the view of fragment is null. So you can do:
#Override
public void onResume() {
super.onResume();
TextView txt = ( TextView ) getActivity().findViewById(R.id.txt);
txt.setText("nayak nahi , khalnayak hun mein");
}

You can define a ListView in a layout for your Fragment. Try something like this in your fragment to define a alternative layout
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
_baseView = inflater.inflate(R.layout.yourlayout, null); //where base view is your upper most parent in your layout
return _baseView;
}
Then in your onActivityCreated you can use _baseView.findViewById('yourListView') to set your ListView. I don't know if this is best practice but it works perfectly for me.

In Fragment you should use its View but getActivity:
public View onCreateView(…){
View rootView = inflater.inflate(R.layout.listview_xml_file, container, false);
ListView ListNewsBelarus = (ListView) rootView.findViewById(R.id.listViewId);
return rootView;
}

setText in a ListFragment

I'm a beginner at Android programming and I was wondering if you could help me out.
I have a ListFragment:
public class AdvertFrag extends ListFragment implements LoaderManager.LoaderCallbacks<Cursor>
that I'm populating from a database using a loaderManager. This works fine and displays details of adverts, but I would like to do some calculations (work out distance via longitude and latitude) and then have the distance to the shops location displayed on each AdvertFrag.
I have looked into using setText() on a TextView in a fragment and have read you should allow the onCreateView method to be called first so a view is present. I have tried the below code:
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
view = inflater.inflate(R.layout.row, container, false);
if(view == null)
{
Log.i("TEST","null");
}
else
{
distance = (TextView) view.findViewById(R.id.distance);
distance.setText("the distance will go here");
}
return view;
}
But get the error that "Your content must have a ListView whose id attribute is android.R.id.list. Allowing the OnCreateView to just call:
return super.onCreateView(inflater, container, savedInstanceState);
works fine.
So my question is, what am I doing wrong? and how do I get setText working in a ListActivity? Or am i going at it in totally the wrong way?
Addition info if its useful:
My row.xml, just has the text views that are populated by the loader and the additional textview for the distance.
I have a fragmentActivity that has the fragment in its XML, like so:
<fragment
...
android:name="com.example.goclub.AdvertFrag"
.../>

Like user113215 said onCreateView() of the ListFragment is not a place to change widgets inside the list items. You will have to create a custom CursorAdapter for that assuming that you are using one. You can find a nice tutorial about this here. Basically it extends a SimpleCursorAdapter and makes changes in the bindView method.