Button Listener for button in fragment in android

Question

I am new to Android and trying to learn on my own  But I am having a tough time with Fragments  I am creating a simple application to learn fragments  I think it may seem silly but I really can t get this to work   All I want to do is on the click of a button  buttonSayHi  in Fragment One  Fragment One should be replaced by Fragment Two   I am not sure when the Fragment code is called and where am I supposed to write my code to call the second fragment  I get the error  Unable to start Activity component   However  the code works fine if I discard the listener for button and the fragment is displayed within the activity   I have done considerable research  read the fragments tutorial on developer android com and also the tutorial by Lars Vogella  I think my concepts are not clear   Any help will be appreciated   The following is the code   activity main xml   lt FrameLayout xmlns android  http   schemas android com apk res android      android id    id frameLayoutFragmentContainer      android layout width  fill parent      android layout height  fill parent   gt    lt  FrameLayout gt    fragment one xml   lt  xml version  1 0  encoding  utf-8   gt    lt LinearLayout xmlns android  http   schemas android com apk res android      android layout width  fill parent      android layout height  fill parent      android orientation  vertical   gt        lt EditText         android id    id editTextPersonName          android layout width  fill parent          android layout height  wrap content          android ems  10          android inputType  textPersonName   gt            lt requestFocus   gt       lt  EditText gt        lt Button         android id    id buttonSayHi          android layout width  fill parent          android layout height  wrap content          android text  Say Hi           android onClick  onButtonClicked   gt    lt  LinearLayout gt    fragment two xml   lt  xml version  1 0  encoding  utf-8   gt   lt LinearLayout xmlns android  http   schemas android com apk res android      android layout width  fill parent      android layout height  fill parent      android orientation  vertical   gt        lt TextView         android id    id textViewResult          android layout width  fill parent          android layout height  wrap content          android text  I will say Hi     gt    lt  LinearLayout gt    MainActivity java  package com example fragmenttutorial   import android os Bundle  import android view View  import android widget Button  import android app Activity  import android app Fragment  import android app FragmentManager  import android app FragmentTransaction   public class MainActivity extends Activity       View view      FragmentManager fragmentManager   getFragmentManager        FragmentTransaction fragmentTransaction   fragmentManager beginTransaction          Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity main                 Fragment fragmentOne   new FragmentOne             fragmentTransaction add R id frameLayoutFragmentContainer  fragmentOne           fragmentTransaction addToBackStack null            fragmentTransaction commit               protected void onButtonClicked                 if view getId      R id buttonSayHi               Fragment fragmentTwo   new FragmentTwo                 fragmentTransaction replace R id frameLayoutFragmentContainer  fragmentTwo               fragmentTransaction addToBackStack null                fragmentTransaction commit                             FragmentOne java  package com example fragmenttutorial   import android app Fragment  import android app FragmentManager  import android app FragmentTransaction  import android os Bundle  import android view LayoutInflater  import android view View  import android view ViewGroup   public class FragmentOne extends Fragment       View view      FragmentManager fragmentManager   getFragmentManager        FragmentTransaction fragmentTransaction   fragmentManager beginTransaction          Override     public View onCreateView LayoutInflater inflater  ViewGroup container              Bundle savedInstanceState             View view   inflater inflate R layout fragment one  container  false           return view             protected void onButtonClicked                 if view getId      R id buttonSayHi               Fragment fragmentTwo   new FragmentTwo                   fragmentTransaction replace R id frameLayoutFragmentContainer  fragmentTwo               fragmentTransaction addToBackStack null                  fragmentTransaction commit                                 I have commented out the on click code in the fragment  I have also tried implementing the onClickListener in the fragment   FragmentTwo java  package com example fragmenttutorial   import android app Fragment  import android os Bundle  import android view LayoutInflater  import android view View  import android view ViewGroup   public class FragmentTwo extends Fragment        Override     public View onCreateView LayoutInflater inflater  ViewGroup container              Bundle savedInstanceState             View view   inflater inflate R layout fragment two  container  false           return view                EDIT  I have removed the line android onClick  onButtonClicked  from my code in XML  And edited the following files but it still does not work  Can you guys provide me a working example without the android onClick  onButtonClicked  line   MainActivity java  package com example fragmenttutorial   import android os Bundle  import android view View  import android app Activity  import android app Fragment  import android app FragmentManager  import android app FragmentTransaction   public class MainActivity extends Activity       View view      Fragment fragmentOne      FragmentManager fragmentManager   getFragmentManager        FragmentTransaction fragmentTransaction   fragmentManager beginTransaction          Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity main                 fragmentOne   new FragmentOne             fragmentTransaction add R id frameLayoutFragmentContainer  fragmentOne           fragmentTransaction addToBackStack null            fragmentTransaction commit                     FragmentOne java  package com example fragmenttutorial   import android app Fragment  import android app FragmentManager  import android app FragmentTransaction  import android os Bundle  import android view LayoutInflater  import android view View  import android view View OnClickListener  import android view ViewGroup  import android widget Button   public class FragmentOne extends Fragment implements OnClickListener       View view      Fragment fragmentTwo      FragmentManager fragmentManager   getFragmentManager        FragmentTransaction fragmentTransaction   fragmentManager beginTransaction          Override     public View onCreateView LayoutInflater inflater  ViewGroup container              Bundle savedInstanceState             View view   inflater inflate R layout fragment one  container  false           Button buttonSayHi    Button  view findViewById R id buttonSayHi           buttonSayHi setOnClickListener this           return view              Override     public void onClick View v             fragmentTwo   new FragmentTwo             fragmentTransaction replace R id frameLayoutFragmentContainer  fragmentTwo           fragmentTransaction addToBackStack null            fragmentTransaction commit                  Thank you for your valuable suggestions

User · Answer

Try this    FragmentOne java  import android app Fragment  import android app FragmentManager  import android app FragmentTransaction  import android os Bundle  import android view LayoutInflater  import android view View  import android view ViewGroup  import android widget Button   public class FragmentOne extends Fragment       View rootView            Override public View onCreateView LayoutInflater inflater  ViewGroup container          Bundle savedInstanceState             rootView   inflater inflate R layout fragment one  container  false             Button button    Button  rootView findViewById R id buttonSayHi           button setOnClickListener new View OnClickListener                          Override             public void onClick View v                                onButtonClicked v                                     return rootView           public void onButtonClicked View view                  do your stuff here                  final FragmentTransaction ft   getFragmentManager   beginTransaction         ft replace R id frameLayoutFragmentContainer  new FragmentTwo     NewFragmentTag         ft commit          ft addToBackStack null               check this   click here

User · Answer

Your fragment class should implement OnClickListener  public class SmartTvControllerFragment extends Fragment implements View OnClickListener   Then get view  link button and set onClickListener like in example below   View view    Override public View onCreateView LayoutInflater inflater  ViewGroup container  Bundle savedInstanceState         view   inflater inflate R layout smart tv controller fragment  container  false       upButton    Button  view findViewById R id smart tv controller framgment up button       upButton setOnClickListener this       return view       And then add onClickListener method and do what you want    Override public void onClick View v       do what you want to do when button is clicked     switch  v getId              case R id textView help              switchFragment HelpFragment TAG               break          case R id textView settings              switchFragment SettingsFragment TAG               break            This is my example of code  but I hope you understood

User · Answer

Simply pass view object into onButtonClicked function  getView   does not seem to work as expected inside fragment  Try this code for your FragmentOne fragment  PS  you have redefined object view in your original FragmentOne code   package com example fragmenttutorial   import android app Fragment  import android app FragmentManager  import android app FragmentTransaction  import android os Bundle  import android view LayoutInflater  import android view View  import android view ViewGroup   public class FragmentOne extends Fragment       FragmentManager fragmentManager   getFragmentManager        FragmentTransaction fragmentTransaction   fragmentManager beginTransaction          Override     public View onCreateView LayoutInflater inflater  ViewGroup container              Bundle savedInstanceState             View view   inflater inflate R layout fragment one  container  false           onButtonClicked view           return view           protected void onButtonClicked View view            if view getId      R id buttonSayHi             Fragment fragmentTwo   new FragmentTwo               fragmentTransaction replace R id frameLayoutFragmentContainer  fragmentTwo             fragmentTransaction addToBackStack null              fragmentTransaction commit

User · Answer

Use your code  public class FragmentOne extends Fragment implements OnClickListener       View view      Fragment fragmentTwo      FragmentManager fragmentManager   getFragmentManager        FragmentTransaction fragmentTransaction   fragmentManager beginTransaction          Override     public View onCreateView LayoutInflater inflater  ViewGroup container              Bundle savedInstanceState             View view   inflater inflate R layout fragment one  container  false           Button buttonSayHi    Button  view findViewById R id buttonSayHi           buttonSayHi setOnClickListener this           return view          But I think is better handle the buttons in this way    Override     public void onClick View v            switch v getId                 case R id buttonSayHi                  Do things you need to                  fragmentTwo   new FragmentTwo                    fragmentTransaction replace R id frameLayoutFragmentContainer  fragmentTwo                  fragmentTransaction addToBackStack null                   fragmentTransaction commit                                 break

User · Answer

This works for me   private OnClickListener mDisconnectListener  mDisconnectListener   new OnClickListener               Override         public void onClick View v                   TODO Auto-generated method stub                             onCreateView        mButtonDisconnect    Button  rootView findViewById R id button disconnect   mButtonDisconnect setOnClickListener mDisconnectListener

User · Answer

Fragment Listener  If a fragment needs to communicate events to the activity  the fragment should define an interface as an inner type and require that the activity must implement this interface   import android support v4 app Fragment   public class MyListFragment extends Fragment                 Define the listener of the interface type      listener is the activity itself   private OnItemSelectedListener listener        Define the events that the fragment will use to communicate   public interface OnItemSelectedListener       public void onRssItemSelected String link             Store the listener  activity  that will have events fired once the fragment is attached    Override   public void onAttach Activity activity        super onAttach activity         if  activity instanceof OnItemSelectedListener            listener    OnItemSelectedListener  activity          else           throw new ClassCastException activity toString                   must implement MyListFragment OnItemSelectedListener                      Now we can fire the event when the user selects something in the fragment   public void onSomeClick View v         listener onRssItemSelected  some link            and then in the activity   import android support v4 app FragmentActivity   public class RssfeedActivity extends FragmentActivity implements   MyListFragment OnItemSelectedListener       DetailFragment fragment      Override   protected void onCreate Bundle savedInstanceState          super onCreate savedInstanceState         setContentView R layout activity rssfeed         fragment    DetailFragment  getSupportFragmentManager                findFragmentById R id detailFragment             Now we can define the action to take in the activity when the fragment event fires    Override   public void onRssItemSelected String link          if  fragment    null  amp  amp  fragment isInLayout                fragment setText link

User · Answer

You only have to get the view of activity that carry this fragment and this could only happen when your fragment is already created   override the onViewCreated   method inside your fragment and enjoy its magic         Override public void onViewCreated View view   Nullable Bundle savedInstanceState        super onViewCreated view  savedInstanceState       Button button    Button  view findViewById R id YOURBUTTONID       button setOnClickListener new View OnClickListener              Override         public void onClick View view               place your action here                      Hope this could help you

User · Answer

sure run it i will also test it   we make a class that extends with the fragment     public class Example 3 1 extends Fragment  implements OnClickListener              View vi          EditText t          EditText t1          Button bu      that are by defult function of fragment extend class       Override        public View onCreateView LayoutInflater inflater ViewGroup container BundlesavedInstanceState                               vi inflater inflate R layout example 3 1  container  false     load the xml file             bu  Button  vi findViewById R id button1     get button id from example 3 1 xml file            bu setOnClickListener this     on button appay click listner            t  EditText  vi findViewById R id editText1     id get from example 3 1 xml file            t1  EditText  vi findViewById R id editText2             return vi     return the view object that set the xml file  example 3 1 xml file                  Override        public void onClick View v   on button click that called                     switch v getId      on run time get id what button os click and get id                       case R id button1            it mean if button1 click then this work            t setText  UMTien          set text             t1 setText  programming               break

User · Answer

While you are declaring onclick in XML then you must declair method and pass View v as parameter and make the method public      Ex    in xml android onClick  onButtonClicked       in java file public void onButtonClicked View v      your code here

[android] Button Listener for button in fragment in android

FragmentOne.java

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