I decided to switch from multiple activities to one activity which switches between fragments however the application now crashes.
Here is the activity I am adding the fragment to
public class MainActivity extends SherlockFragmentActivity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
MyFragment fragment = new MyFragment();
fragment.setArguments(getIntent().getExtras());
getSupportFragmentManager().beginTransaction()
.add(R.id.fragment_container, fragment).commit();
}
Here is the fragment its an observer and has functionality but to save space ill just show the creation
public class MyFragment extends SherlockFragment implements Observer{
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.my_fragment, container, false);
}
Heres my_fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/my_fragment"
android:layout_width="match_parent"
android:layout_height="match_parent" >
... HAS SOME TEXT VIEWS HERE!
</RelativeLayout>
The crash I get is
02-15 16:17:41.079: E/AndroidRuntime(18668): FATAL EXCEPTION: main
02-15 16:17:41.079: E/AndroidRuntime(18668): java.lang.RuntimeException:
Unable to start activity ComponentInfo{com.example.myapp/com.example.myapp.MainActivity}:
java.lang.IllegalArgumentException:
No view found for id 0x7f040036 for fragment MyFragmentt{41a05910 #0 id=0x7f040036}
Can anyone help me out here? I can't really figure out what is causing this. I know if I comment out getSupportFragmentManager() in main activity (the top code block in this post) it will run just not draw anything in my fragment.
UPDATE
The frame_container which I'm not sure where to place
<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" />
So the way you can use Fragments in your applications are two.
First way is if you declare the Fragment in your xml file like this :
<fragment android:name="com.example.news.ArticleReaderFragment"
android:id="#+id/viewer"
android:layout_weight="2"
android:layout_width="0dp"
android:layout_height="match_parent" />
The second way is if you add / replace your Fragments dynamically to your container which in the most examples is FrameLayout. Here is how you can do that :
In your main FragmentActivity :
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.myFragmentContainer);
}
and in your xml myFragmentContainer.xml is where you place your fragment_container and it looks like :
<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" />
and you are adding and replacing your Fragments like this :
if (findViewById(R.id.fragment_container) != null) {
if (savedInstanceState != null) {
return;
}
// Create an instance of ExampleFragment
HeadlinesFragment firstFragment = new HeadlinesFragment();
// if there are any extras
firstFragment.setArguments(getIntent().getExtras());
// Add the fragment to the 'fragment_container' FrameLayout
getSupportFragmentManager().beginTransaction()
.add(R.id.fragment_container, firstFragment).commit();
}
and for the next Fragment which you want to show just do :
getSupportFragmentManager().beginTransaction()
.replace(R.id.fragment_container, secondFragment).commit();
Related
even though i googled extensively, i cant find a solution to my problem. I am new to programming, so please consider that in your answer.
I have a Main Activity and a Menu bar at the bottom. Since the menu bar is scrollable and i want to have it for all the different screens, i figured out that i could - instead of making an intent for a new activity - just put a fragment on top of the existing screen (and spare out the menu bar).
But i fail at programatically opening that fragment. I tried the following, but it doesnt even recognice the ID of the FrameLayout.
I was trying to replace a FrameLayout in my Main Activities' xml file with the fragment:
FragmentManager fragmentManager = getSupportFragmentManager();
android.support.v4.app.FragmentTransaction ft =
fragmentManager.beginTransaction();
ft.replace(R.id.idOfFrameLayout, new nameOfFragmentClass());
ft.commit();
EDIT:
It works after i implemented OnFragmentInteractionListener into the Main Activity. Thanks to everyone!
My original answer suggested using add instead of replace for the Fragment transaction. I have since learned that either can be used in this case. For more info on the differences, see this, this and this
Since my add/replace idea was off base, I've changed my answer to a simple Fragment tutorial. One Fragment inflated from one Activity. I've included the code for Fragment to Activity communication (the reason for the OPs problem) but left comments on what could be deleted if that's not needed. The only thing done in the Activity is launching the Fragment then receiving a message back from that Fragment. The Fragment has a button that will cause a message to be sent back to the Activity. The message will then be Logged.
In both classes, if no communications is needed from the Fragment to the Activity, delete anything that is marked TODO:
// this is what controls whether you use a Fragment from the support library
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
public class SimpleActivity extends AppCompatActivity
// TODO: delete "implements SimpleFragment.OnFragmentInteractionListener" from this
// line (leave the '{')
implements SimpleFragment.OnFragmentInteractionListener {
private static final String TAG = SimpleActivity.class.getSimpleName();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_simple);
SimpleFragment fragment = new SimpleFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.add(R.id.fragment_container, fragment)
.commit();
}
// TODO: this entire method can be deleted
#Override
public void onFragmentInteraction(String message) {
// This is where you can act on the message from the Fragment. You would do
// things that are done from an Activity or you may pass the message on
// to another Fragment.
Log.d(TAG, message);
}
}
Most import statements aren't shown, I left this one in to indicate using the support library
import android.support.v4.app.Fragment;
public class SimpleFragment extends Fragment {
private OnFragmentInteractionListener mListener; // TODO: delete this line
public SimpleFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate(R.layout.fragment_simple, container, false);
Button button = (Button)rootView.findViewById(R.id.msg_button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// TODO: delete these 3 lines, do something else with the button click
if (mListener != null) {
mListener.onFragmentInteraction("Message from Fragment");
}
}
});
return rootView;
}
// TODO: this entire method can be deleted
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
// TODO: this entire method can be deleted
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
// TODO: this entire method can be deleted
public interface OnFragmentInteractionListener {
void onFragmentInteraction(String message);
}
}
Now the layout files. 1st activity_simple.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/fragment_container"
>
</FrameLayout>
</android.support.constraint.ConstraintLayout>
Then fragment_simple.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="Info to Activity"
android:id="#+id/msg_button"
/>
</RelativeLayout>
This is a very basic sample. Here is a more extensive guide for Fragment usage.
When you use the 'replace' method, you need 3 things:
1- the container id, which is the view that is going to hold your fragment's view.
2- the fragment instance you want to use and
3- the fragment instance's tag, but this is optional.
Given that, let's say you have the following layout for your activity:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
...
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<FrameLayout
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</android.support.v4.widget.NestedScrollView>
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:background="?android:attr/windowBackground"
app:menu="#menu/navigation" />
</android.support.design.widget.CoordinatorLayout>
The FrameLayout which id is "container" is the holding view, so that's the id you've gotta use:
ft.replace(R.id.container, new nameOfFragmentClass());
I suggest use this library to manage fragments:
FragmentManagerAndroid
I am trying to figure out why I am suddenly getting an error when I try to add a fragment.
public class MainActivity extends Activity implements Communicator {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView((int) R.layout.activity_main);
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.add(R.id.fragA, new FragmentA());
//I get errors on each of the adds
ft.commit();
FragmentTransaction ft2 = getFragmentManager().beginTransaction();
ft2.add(R.id.fragB, new FragmentB());
ft2.commit();
FragmentTransaction ft3 = getFragmentManager().beginTransaction();
ft3.add(R.id.fragC, new FragmentC());
ft3.commit();
}
public void respond(String str) {
//I also get an error on the following line
((FragmentB)getFragmentManager().findFragmentById(R.id.fragB)).changeText(str);
}
}
Just using the import of FragmentTransaction, I haven't made my own class.
This is my fragment A code:
public class FragmentA extends Fragment implements OnClickListener {
Button btn;
Communicator comm;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fraga, container, false);
}
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
this.btn = (Button) getActivity().findViewById(R.id.buttonA);
this.btn.setOnClickListener(this);
this.comm = (Communicator) getActivity();
}
public void onClick(View v) {
this.comm.respond("Hello from Fragment A");
}
}
xml for the activity, I am not a hundred percent sure if this will fix it but would raising the API of the project make any difference at all?
<?xml version="1.0" encoding="utf-8"?>
<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"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.tannerlangan.week11fragtalk.MainActivity">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="150dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:background="#ff83ff3e"
android:id="#+id/fragA"></RelativeLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="150dp"
android:layout_centerVertical="true"
android:layout_alignParentStart="true"
android:background="#ff71e7ff"
android:id="#+id/fragB"></RelativeLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="150dp"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:background="#ff6d9aff"
android:id="#+id/fragC"></RelativeLayout>
</RelativeLayout>
Your fragments probably using android.support.v4.app.Fragment instead of android.app.Fragment. The quick fix is to change the signature of your fragments to something like this:
public class FragmentA extends android.app.Fragment implements OnClickListener
This is very common with programs that mix the components from support libraries and the non-support one
Try using getSupportFragmentManager() instead of getFragmentManager(). getSupportFragmentManager() is for API<14.
In your project check whether you have imported the same Fragment class in both your FragmentA and MainActivity. You might have imported android.support.v4.app.Fragment in your fragment and in MainActivity you may have imported android.app.Fragment.
If you're minSdk is <14 use fragment, fragmentManager etc from the support library(i.e android.support.v4.app.fragment and same for the fragment manager) else just import the standard fragment class(i.e android.app.Fragment).
P.S : It would be really helpfull if you provide your Error in the question as well.
Solved! Thanks everyone for your help.
I am struggling with Fragments as a concept, and especially seem stuck on this one thing. What I'm trying to do is, using my fragment, manipulate its own layout's data. Every time I try to access an ImageButton from within the Fragment, it crashes the application. It works fine from the activity. Am I just misunderstanding Fragments fundamentally?
Code(cut down for size)-
This is the beginning of the activity my fragment is called from:
Display.java
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display);
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
MyFragmentClass MyFragment = new MyFragmentClass();
fragmentTransaction.add(R.id.fragment_container, MyFragment);
fragmentTransaction.commit();
The XML for that Activity:
activity_display.xml
<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"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="com.mycompanyname.myprojectname.Display"
android:id="#+id/display_layout">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/fragment_container">
</FrameLayout>
</RelativeLayout>
The Fragment
MyFragmentClass.java
public class MyFragmentClass extends Fragment
{
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_layout_screen, container, false);;
}
public void MethodTest()
{
}
}
The Fragment's XML file:
fragment_layout_screen.xml
<?xml version="1.0" encoding="utf-8"?>
<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"
android:id="#+id/fragment_layout_screen"
tools:context="com.mycompanyname.myprojectname.MyFragmentClass">
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/my_button"
android:clickable="true"
android:onClick="buttonPress"
android:src="#drawable/button"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"/>
</RelativeLayout>
Basically I had all of this originally in Display.java, but wanted to add fragments, so I'm trying to move stuff out and into fragments, but I still need the ability to manipulate the xml info, I just can't.
From inside the Display.java activity I can easily call the ImageButton like this:
ImageButton myButton = (ImageButton) findViewById(R.id.my_button)
but if I do the same from MethodTest in the fragment, the app crashes.
I've searched many suggestions on here, trying various solutions from here: findViewById in Fragment but none of those seemed to work.
I've been reading through this for the setup: http://developer.android.com/guide/components/fragments.html and can't seem to find what I'm doing wrong.
Any help would be appreciated, and if you have any questions about my setup, please ask.
declare on fragment private View rootView;
On the onCreateView(...) set rootView = inflater.Inflate(..); and then access the imagebutton as ImageButton mButton =(ImageButton) rootView.findViewById(..);
Do like this in fragment
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.gridview, container, false);
GridView gridview = (GridView) view.findViewById(R.id.grid);
return view ;
I'm quite new to Android dev and I followed the official Android's "Get started".
The fact is, my fragment is not displayed on the main activity ( it worked well few days ago but I changed some lines, I don't remember which ones ). I think it's a very basic problem as I don't use sophisticated fragments : it's basically one fragment inside an activity.
This is my activity :
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container1"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.mysecond.MainActivity"
tools:ignore="MergeRootFrame" />
My fragment :
<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"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />
</RelativeLayout>
And the java code for this activity (I have some other activities in the app, based on the same pattern "one fragment inside one activity" and they work well...)
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container1, new PlaceholderFragment()).commit();
}
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
return rootView;
}
}
}
Any ideas ?
Thank you :)
[edit]
so this is my new onCreate method :
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getSupportFragmentManager().beginTransaction().replace(
R.id.container1, new PlaceholderFragment()).commit();
}
Still not working for this activity (If I add a button in activity_main.xml I'll be able to see it but the I'm not able to see the TextView in the fragment...)
No errors in logcat and yes the activity is launched (I added some Log.e in onCreate and onCreateView and I cas see them)
In your onCreate methode you don't have to check if the savedInstanceState is null but if the the content of the FrameLayout you use is null
Or you simply always replace the fragment with a new one and ommit any checking.
Instead of add, you can use replace.
You can do it like below shown code:
getSupportFragmentManager().beginTransaction().replace(
R.id.container1, new PlaceholderFragment());
For me this work. Implementa a interface FragmentActions with the init() method and use this
private void showFragment(String fragmentTag){
FragmentTransaction trasaction = getSupportFragmentManager().beginTransaction();
FragmentActions fragment = (FragmentActions) getSupportFragmentManager().findFragmentByTag(fragmentTag);
if(fragment==null ){
if(lastFragmentviewed!=null)
trasaction.hide(lastFragmentviewed);
fragment = (FragmentActions) newInstance(fragmentTag);
trasaction.add(R.id.content_frame,(Fragment) fragment,fragmentTag);
}else{
if(lastFragmentviewed!=null && !lastFragmentviewed.equals(fragment))
trasaction.hide(lastFragmentviewed);
if(getSupportFragmentManager().findFragmentByTag(fragmentTag)!=null){
fragment.init();
trasaction.show((Fragment) fragment);
}else
trasaction.add(R.id.content_frame,(Fragment) fragment,fragmentTag);
}
lastFragmentviewed=(Fragment) fragment;
trasaction.commit();
}
So, I'm trying to put together some fragments. I have a TabActivity extending FragmentActivity
Inside the TabActivity i have 4 tabs that extend Fragments(android.support.v4.app.Fragment)
In one of these Fragments i want a google map to take up some part of the screen. I have ViewPager to switch between views within the TabActivity. In my project i have
Android Private Libraries
-Google-play-services.jar
-android-support-v4.jar
And my manifest has my unique API key.
BUT, when i press the tab that should hold a map, i get an empty screen:
The Fragment containing the map:
public class MyTripsFragment extends Fragment
{
private SupportMapFragment fragment;
private GoogleMap map;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
try{
return inflater.inflate(R.layout.view_mytrips, container, false);
}
catch(Exception e){
e.printStackTrace();
}
return null;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
FragmentManager fm = getChildFragmentManager();
fragment = (SupportMapFragment) fm.findFragmentById(R.id.map);
if(fragment == null)
{
fragment = SupportMapFragment.newInstance();
map = fragment.getMap();
fm.beginTransaction().replace(R.id.map, fragment).commit();
}
}
And the XML(From what i've read should NOT contain a Fragment because of my viewpager,
IllegalStateException when replacing a Fragment)
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/mapContainer">
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/map">
</RelativeLayout>
</RelativeLayout>
So how can i get the map to load a map? Am i missing something small or am i going about this the wrong way? I've tried alot of different things but nothing gets me what i want.