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
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/frameLayoutFragmentContainer"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
</FrameLayout>
fragment_one.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<EditText
android:id="@+id/editTextPersonName"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPersonName" >
<requestFocus />
</EditText>
<Button
android:id="@+id/buttonSayHi"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Say Hi"
android:onClick="onButtonClicked"/>
</LinearLayout>
fragment_two.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/textViewResult"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="I will say Hi!" />
</LinearLayout>
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.
This question is related to
android
android-fragments
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();
}
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
}
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 && fragment.isInLayout()) {
fragment.setText(link);
}
}
}
//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;
}
} }
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 ;
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
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);
...
}
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;
}
}
Try this :
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
Source: Stackoverflow.com