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.
Related
i have try a lot of example or tutorial on tablayout, all work fine
(https://www.simplifiedcoding.net/android-tablayout-example-using-viewpager-fragments/, http://www.androidbegin.com/tutorial/implementing-fragment-tabs-in-android/)
but now i encounter 1 problem, which is i dont know how to set/change the TextView/ImageView while onCreate/onLoad
so far, what i able to do is, write all my code under onTabSelected, but this is not my solution because i cant show empty or static values on the 1st tab, then have to wait until click or slide again then only load the real data.
i'm sure it have a way or solution for my problem, can anyone share it to me (code/website)
or in order to have this Tab feature with viewpager contain recyclerview, Tablayout is not the right way to code, perhaps it have another more correct way to code.
Do these changes inside of onCreateView of fragment that you want
Example:
//Our class extending fragment
public class Tab1 extends Fragment {
//Overriden method onCreateView
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
//Change R.layout.tab1 in you classes
View view = inflater.inflate(R.layout.tab1, container, false);
TextView textView = (TextView) view.findViewById(R.id.you_textview_id);
textView .setText("Your text to show");
//Returning the layout file after inflating
return view;
}
}
The TextView need to be previous declared in tab.xml that you're inflating, in our example, tab1.
Inside the dialogFragment I have viewPager with two pages. Every page contains a custom adapter. One adapter with list of spinners, other adapter with list of EditTexts. ViewPager adds adapters fine.
public class PageFragment extends Fragment {
...
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.pagefragment_newprod, null);
LinearLayout ll=(LinearLayout) view.findViewById(R.id.tvLL);
ListView listView=new ListView(getActivity());
ll.addView(listView);
if (pageNumber==0){
dropDownAdapter=new DropDownAdapter(getActivity(), fillListAdapter);
listView.setAdapter(dropDownAdapter);
} else if (pageNumber==1){
boxAdapter = new BoxAdapter(getActivity(), filledFields);
listView.setAdapter(boxAdapter);
}
return view;
}
}
But it works to slow! Current Adapter (I mean at the curren page) create views every milisecond! Look at this:
public class BoxAdapter extends BaseAdapter{
...
#Override
public View getView(final int position, View convertView, ViewGroup parent) {
if (view == null) {
view = lInflater.inflate(R.layout.addproduct_item, parent, false);
}
Log.d(LOG_TAG, "====As I said every milisecond...======");
EditText editText = (EditText) view.findViewById(R.id.addProductEditText);
editText.setText(p.value);
return view;
}
}
Even when I focused the EditText this Log.d write messages every milisecond!
Besides that, adapter at the next page works too. I have other Log.d at the other adapter getView and it works when I used different page's adapter!
Please help me to understand what is wrong...(
The question has already been solved in the comments. The solution for the OP was apparently to remove complex fragments and their adapter. However, I also had complex fragments in a tab layout with a ViewPager, and the following solution fixed the slow paging problem:
viewPager.setOffscreenPageLimit(2);
The 2 will keep two pages away from the current page in memory. This was enough for me because I had three tabs. Be careful about keeping too many pages in memory, though. See the documentation.
I am beginner in android.
I was having a requirement similar to what is discussed here:
Separate Back Stack for each tab in Android using Fragments.
Now, I am using that project given here gitHub
What I want is to add listview to a fragment..Further on clicking a particular item in list another fragment is visible.
But I am facing a problem in doing it.
For eg here,I get error in using setListAdapter(adapter) function.
Plz help.
public class AppTabAFirstFragment extends BaseFragment {
private Button mGotoButton;
//private String[] characters= {"shs","sds","sdss","sdsd"};
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.app_tab_a_first_screen, container, false);
mGotoButton = (Button) view.findViewById(R.id.id_next_tab_a_button);
mGotoButton.setOnClickListener(listener);
// ArrayAdapter<String> adapter = new ArrayAdapter<String>(inflater.getContext(),R.layout.app_tab_d_first_screen, characters);
// setListAdapter(adapter);
return view;
}
In this way,it doesn't allow us to use setListAdapter() function reason being I can't extend ListActivity. I am all confused.
Kindly help.
I haven't checked your links, but as I can see from the little code you posted I think this might be the problem:
You need to lookup your listview from the xml file (if you have defined it there) and set the adapter to that object. For instance:
ListView listView = (ListView) view.findViewById(R.id.my_list_view);
listView.setAdapter(adapter);
I want to have a fragment for each item in a listview, because I want to separate some logic out. I am using a view holder for each item. If the view doesn't exist, I create a new fragment and add it into the container.
holder.mMyFragment = new MyFragment(mActivity, this);
mActivity.getSupportFragmentManager().beginTransaction().add(R.id.my_container, holder.mMyFragment).commit();
Also for each item, I call holder.mMyFragment.setUi(dataSource, position) to set UI of the fragment based on the data source and position.
The problem I'm having is I initialize the UI elements of fragment in onCreateView method of the fragment class, but it's not called when I add the fragment to the item. So later when I call setUi() which uses some UI elements in fragment it complains a NullPointerException. Does anyone have a suggestion? Thanks!
"THERE IS A SOLUTION" for this.
The issue is, you cannot add fragment directly to the container(FrameLayout) with same "id" in listview as you have done in the above code.
The trick is, create listview(Recyclerview) of "LinearLayout". Then dynamically create FrameLayout in adapter and assign different id's for each. Inflate Fragment to FrameLayout and this FrameLayout to LinearLayout.
#Override
protected void onBindBasicItemView(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof VideoHomeViewHolder) {
VideoHomeViewHolder videoHomeViewHolder = (VideoHomeViewHolder) holder;
FrameLayout frameLayout = new FrameLayout(mContext);
frameLayout.setId(position+1); //since id cannot be zero
FragmentHelper.popBackStackAndReplace(mFragmentManager, frameLayout.getId(),
new ShowLatestVideosFragment(mShowLatestVideosItems.get(position)));
videoHomeViewHolder.linearLayout.addView(frameLayout);
}
}
I want to have a fragment for each item in a listview, because I want to separate some logic out.
You can't use fragment as list item views because the API doesn't allow you - View and Fragment aren't even related so there's no way you can use it like that. Make custom views and use adapter getViewTypeCount and getView to use different list item behavior.
Fragment are managed by Activity's FragmentManager or by other Fragments child FragmentManager; while list item views are managed by ListView & ListAdapter. You can use ListViews in Fragments, but not the other way around.
A simple way.
One problem:You should store add restore fragment state.
holder.mMyFragment = new MyFragment(mActivity, this);
int id = View.generateViewId();
findViewByTag("abc").setId(id);
mActivity.getSupportFragmentManager().beginTransaction().add(id, holder.mMyFragment).commit();
Hi I was facing the same problem and I found the way to do it.
My problem was similar to you:
"I want to have a fragment for each item in a listview, because I want to separate some logic out"
In my app I have to give the option to display custom items in vertical (listView) and horizontal (ViewPager) mode. Additionally I had to deal with 18 custom items and each one with different logic, so the best approach was reusing the fragments that I was using for ViewPager in ListView.
I got it but not in the way you were trying, I mean, I used my fragments like "ViewHolders":
Define fragment's widget like variables of class in each fragment.
Create a custom ArrayAdapter and override: getViewTypeCount(), getItemViewType(int position), getCount(), getItem(int position) getView(int position, View convertView, ViewGroup parent)
In getView I checked what kind of layout I needed before "inflate" the respective XML, create a fragment, assign widget from XML to fragment (with rootView.findViewById) and set "tag" with the new fragment.
What you can see at this point is that fragments in ListView never got attached to Activity but you got what you wanted: logic distributed in several parts and all benefits of ListView (reuse of rows, scroll, etc).
If you need I can post part of my code but you have to deal with "spanglish" ;).
UPDATED
All the problem is because when you create a Fragment to be used with ViewPager, usually all "layout and "setup" code is inside onCreateView method, I mean:
Get the view object you are going to use (View rootView = inflater.inflate(R.layout.fragment_question_horizontal_container, container, false);)
Get the widgets from above layout, define behaviors, fonts, etc: (answer = (EditText)rootView.findViewById(R.id.answer_question_text);)
Until this point there is nothing weird.
If you are going to use a fragment with the behavior described above you have to "emulate" the call to onCreateView, fill the data and attach it to the listView.
Here is the trick: split the code in onCreateView in some methods that doesn't care about who's calling them. An example of my onCreateView:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_pregunta_horizontal_container, container, false);
addAnswerLayout(rootView, R.layout.fragment_pregunta_texto, getActivity());
setUpComponents(rootView);
//those 2 methods are about my app logic so I'm not going to talk much about them
setUpQuestionState(savedInstanceState);
readSavedAnswer();
return rootView;
}
public void addAnswerLayout(View rootView, int optionId, Context context) {
mContext = context;
RelativeLayout relativeLayout = (RelativeLayout)rootView.findViewById(R.id.pregunta_container);
LayoutInflater inflater = ((Activity)mContext).getLayoutInflater();
View newView = inflater.inflate(optionId, relativeLayout, false);
relativeLayout.addView(newView);
}
public void setUpComponents(View rootView) {
//next line: some heritage that you can ignore
super.setUpComponents(rootView);
respuesta = (EditText)rootView.findViewById(R.id.pregunta_respuesta_texto);
respuesta.setTypeface(UiHelper.getInstance(getActivity()).typeface);
respuesta.setTextColor(mContext.getResources().getColor(R.color.drs_gris));
...
}
Now let's go to the CustomArrayAdapter for list view:
Define your customArrayAdapter something like this: PreguntasVerticalArrayAdapter extends ArrayAdapter<Pregunta> where "Pregunta" is a generic Fragment with the logic from above.
Override getViewTypeCount(), getItemViewType(int position), getCount(), getItem(int position) getView(int position, View convertView, ViewGroup parent).
The getView follow the same behavior: get the object for the given position in params, reuse a "viewholder" and fill the data. Here my getView:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View rowView = convertView;
Pregunta pregunta = mData.get(position);
if (rowView == null)
rowView = createQuestionUI(pregunta, parent, position);
fillDataInRow((PreguntaUI)rowView.getTag(), pregunta, position);
return rowView;
}
private View createPreguntaUI(Pregunta pregunta, ViewGroup parent, int position) {
View rootView = null;
LayoutInflater inflater = (mPreguntasVerticalFragment.getActivity()).getLayoutInflater();
//you can ignore this part of the code ralted to Bundle.
Bundle args = new Bundle();
args.putLong(PreguntaUI.PREGUNTAUI_ID, pregunta.getIdpregunta());
args.putInt(PreguntaUI.PREGUNTAUI_INDEX, position);
args.putInt(PreguntaUI.PREGUNTAUI_TOTAL_QUESTIONS, getCount());
//internal method of "pregunta" to know what kind of question it is.
String tipo = pregunta.getTipo();
if (tipo.equalsIgnoreCase(PreguntaType.TEXT.toString())) {
rootView = inflater.inflate(R.layout.fragment_pregunta_vertical_container, parent, false);
Pregunta_texto pregunta_texto = new Pregunta_texto();
pregunta_texto.setArguments(args);
//LOOK AT THIS POINT!!!: I'm calling the same methods that I called in onCreateView fragment's method.
pregunta_texto.addAnswerLayout(rootView, R.layout.fragment_pregunta_texto,
mPreguntasVerticalFragment.getActivity());
pregunta_texto.setUpComponents(rootView);
pregunta_texto.setUpQuestionState(null);
pregunta_texto.readSavedAnswer();
//I'm adding the fragment to reuse it when I can
rootView.setTag(pregunta_texto);
}
else if ...
return rootView;
}
That is all... at this point, if you have enough experience dealing with CustomArrayAdapters and Fragments you probably got it! :D
From the Android Documentation : "A Fragment represents a behavior or a portion of user interface in an Activity. You can combine multiple fragments in a single activity to build a multi-pane UI and reuse a fragment in multiple activities."
For your activity, do you want to add 2 fragments where the first one displays a listView (= ListFragment and the other one is in the right and is shown only when the user clicks on an item (from the first fragment or listView) ?
Instead of using ListFragment, you can use RecyclerView, Android has documentation on that:
https://developer.android.com/training/basics/fragments/creating.html#AddInLayout
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