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Fragment tab not attached to a context

I'm currently making a soundboard app on android studio which has a ton of fragments. The first page on my tab layout is just a normal button view, but my second tabView has another fragmentView within it. The goal is for the first page to just show some normal sounds, and the second tab to have multiple operators to choose specific soundboards for.
Anyways, the app seems to work fine. I can switch from the main tab to the operator tab, and even select operator soundboard pages and be moved to their fragments. However as soon as I try to switch fragments (through my tabview) my app crashes and I get the error:
"Fragment operatorTab{4623fc9} (312d4e58-458c-4f47-8fa3-794fe15f0536)} not attached to a context."**
**at com.jkcarraher.rainbowsixsoundboard.operatorTab.resetAllButtons(operatorTab.java:113)
at com.jkcarraher.rainbowsixsoundboard.operatorTab.access$000(operatorTab.java:31)
at com.jkcarraher.rainbowsixsoundboard.operatorTab$2.onScrollChanged(operatorTab.java:107)
I attached my code below, please let me know if you have any ideas!
MainActivity.java
import android.graphics.Color;
import android.os.Bundle;
import android.text.SpannableString;
import android.text.Spanned;
import android.text.style.ForegroundColorSpan;
import android.widget.Adapter;
import android.widget.TextView;
import com.google.android.gms.ads.MobileAds;
import com.google.android.gms.ads.initialization.InitializationStatus;
import com.google.android.gms.ads.initialization.OnInitializationCompleteListener;
import com.google.android.material.tabs.TabLayout;
import androidx.viewpager.widget.ViewPager;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
private SectionsPageAdapter mSectionsPageAdapter;
private ViewPager mViewPager;
private TabLayout tabLayout;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initializeAds();
makeSixYellow();
//Create ViewPager (that houses all fragments)
mSectionsPageAdapter = new SectionsPageAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.view_pager);
setUpViewPager(mViewPager);
//Add & customize tabs
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setTabTextColors(Color.WHITE, Color.WHITE);
tabLayout.setupWithViewPager(mViewPager);
tabLayout.getTabAt(0).setText("Utility");
tabLayout.getTabAt(1).setText("Voice Lines");
checkPageChange();
}
private void setUpViewPager(ViewPager viewPager) {
SectionsPageAdapter adapter = new SectionsPageAdapter(getSupportFragmentManager());
adapter.addFragment(new utilityTab(), "Utility");
adapter.addFragment(new voiceLinesView(), "Voice Lines");
viewPager.setAdapter(adapter);
}
private void makeSixYellow(){
TextView textView = findViewById(R.id.titleText);
String text = "R6 Soundboard";
SpannableString ss = new SpannableString(text);
ForegroundColorSpan fcsYellow = new ForegroundColorSpan(Color.rgb(255,236,141));
ss.setSpan(fcsYellow, 1,2, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
textView.setText(ss);
}
private void initializeAds(){
MobileAds.initialize(this, new OnInitializationCompleteListener() {
#Override
public void onInitializationComplete(InitializationStatus initializationStatus) {
}
});
}
private void checkPageChange(){
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
utilityTab.resetAllButtons();
}
#Override
public void onPageSelected(int position) {
utilityTab.resetAllButtons();
}
#Override
public void onPageScrollStateChanged(int state) {
utilityTab.resetAllButtons();
}
});
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/colorHeader"
android:theme="#style/AppTheme.AppBarOverlay">
<TextView
android:id="#+id/titleText"
android:layout_marginLeft="20dp"
android:layout_marginTop="20dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="#font/avenir"
android:gravity="center_horizontal"
android:text="R6 Soundboard"
android:textColor="#FFF"
android:textSize="30sp" />
<com.google.android.material.tabs.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabTextColor="#fff"
android:background="#color/colorHeader" />
</com.google.android.material.appbar.AppBarLayout>
<androidx.viewpager.widget.ViewPager
android:id="#+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorBody"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
voiceLinesView.java (contains fragments so I can select an operator and it will take me to their soundboard fragment)
package com.jkcarraher.rainbowsixsoundboard;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentTransaction;
import androidx.viewpager.widget.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.google.android.material.tabs.TabLayout;
public class voiceLinesView extends Fragment {
private SectionsPageAdapter voiceLinesSectionsPageAdapter;
private ViewPager voiceLinesViewPager;
public voiceLinesView() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_voice_lines_view, container, false);
FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
fragmentTransaction.add(R.id.voiceLinesFrame, new operatorTab());
fragmentTransaction.commit();
return view;
}
}
fragment_voice_lines_view.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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"
tools:context=".voiceLinesView">
<FrameLayout
android:id="#+id/voiceLinesFrame"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</FrameLayout>
operatorTab.java
package com.jkcarraher.rainbowsixsoundboard;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Rect;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.widget.RelativeLayout;
import android.widget.ScrollView;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import soup.neumorphism.NeumorphCardView;
import soup.neumorphism.ShapeType;
import static android.view.MotionEvent.ACTION_MOVE;
public class operatorTab extends Fragment {
private ScrollView scrollView;
public static RelativeLayout KapkanButton;
public static RelativeLayout GlazButton;
public static RelativeLayout FuzeButton;
public static RelativeLayout TachankaButton;
voiceLinesView voiceLinesView = new voiceLinesView();
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_operator_tab, container, false);
//Initialize ScrollView
scrollView = view.findViewById(R.id.operatorScrollView);
//Initialize buttons 1-4
KapkanButton = view.findViewById(R.id.kapkanButton);
GlazButton = view.findViewById(R.id.glazButton);
FuzeButton = view.findViewById(R.id.fuzeButton);
TachankaButton = view.findViewById(R.id.tachankaButton);
//Make buttons 1-6 pressable
initPressableButton(KapkanButton);
initPressableButton(GlazButton);
initPressableButton(FuzeButton);
initPressableButton(TachankaButton);
scrollResetListener();
return view;
}
#SuppressLint("ClickableViewAccessibility")
private void initPressableButton(final RelativeLayout relativeLayout) {
relativeLayout.setBackgroundColor(getResources().getColor(R.color.colorBody));
final Rect r = new Rect();
relativeLayout.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View view, MotionEvent event) {
// get the View's Rect relative to its parent
view.getHitRect(r);
// offset the touch coordinates with the values from r
// to obtain meaningful coordinates
final float x = event.getX() + r.left;
final float y = event.getY() + r.top;
if(event.getAction() == MotionEvent.ACTION_DOWN) {
relativeLayout.setBackgroundColor(getResources().getColor(R.color.colorButtonPressed));
return true;
} else if(event.getAction() == MotionEvent.ACTION_UP) {
if (r.contains((int) x, (int) y)) {
relativeLayout.setBackgroundColor(getResources().getColor(R.color.colorBody));
//On Click Up
FragmentTransaction fr = getFragmentManager().beginTransaction();
fr.replace(R.id.voiceLinesFrame, new kapkanVoiceLines());
fr.commit();
}
}else if(event.getAction() == ACTION_MOVE){
if (!r.contains((int) x, (int) y)) {
relativeLayout.setBackgroundColor(getResources().getColor(R.color.colorBody));
}
return true;
}
return false;
}
});
}
private void scrollResetListener(){
scrollView.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
#Override
public void onScrollChanged() {
resetAllButtons();
}
});
}
public void resetAllButtons(){
KapkanButton.setBackgroundColor(getResources().getColor(R.color.colorBody));
GlazButton.setBackgroundColor(getResources().getColor(R.color.colorBody));
FuzeButton.setBackgroundColor(getResources().getColor(R.color.colorBody));
TachankaButton.setBackgroundColor(getResources().getColor(R.color.colorBody));
}
}
fragment_operator_tab.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".operatorTab">
<ScrollView
android:id="#+id/operatorScrollView"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/colorBody">
<RelativeLayout
android:id="#+id/kapkanButton"
android:layout_width="match_parent"
android:layout_height="60sp"
android:orientation="horizontal">
<ImageView
android:id="#+id/kapkanIcon"
android:layout_width="50sp"
android:layout_height="50sp"
android:layout_marginTop="5sp"
android:layout_marginLeft="10sp"
android:src="#drawable/ic_kapkan"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/kapkanIcon"
android:layout_marginLeft="10sp"
android:layout_marginTop="15sp"
android:layout_gravity="center"
android:fontFamily="#font/avenir"
android:text="Kapkan"
android:textColor="#ffffff"
android:textSize="25dp" />
<ImageView
android:layout_width="40sp"
android:layout_height="40sp"
android:layout_alignParentEnd="true"
android:layout_marginTop="10sp"
android:layout_marginEnd="10dp"
android:src="#drawable/ic_arrow_right" />
</RelativeLayout>
<RelativeLayout
android:id="#+id/glazButton"
android:layout_below="#+id/kapkanButton"
android:layout_width="match_parent"
android:layout_height="60sp"
android:orientation="horizontal">
<ImageView
android:id="#+id/glazIcon"
android:layout_width="50sp"
android:layout_height="50sp"
android:layout_marginTop="5sp"
android:layout_marginLeft="10sp"
android:src="#drawable/ic_glaz"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/glazIcon"
android:layout_marginLeft="10sp"
android:layout_marginTop="15sp"
android:layout_gravity="center"
android:fontFamily="#font/avenir"
android:text="Glaz"
android:textColor="#ffffff"
android:textSize="25dp" />
<ImageView
android:layout_width="40sp"
android:layout_height="40sp"
android:layout_alignParentEnd="true"
android:layout_marginTop="10sp"
android:layout_marginEnd="10dp"
android:src="#drawable/ic_arrow_right" />
</RelativeLayout>
<RelativeLayout
android:id="#+id/fuzeButton"
android:layout_below="#+id/glazButton"
android:layout_width="match_parent"
android:layout_height="60sp"
android:orientation="horizontal">
<ImageView
android:id="#+id/fuzeIcon"
android:layout_width="50sp"
android:layout_height="50sp"
android:layout_marginTop="5sp"
android:layout_marginLeft="10sp"
android:src="#drawable/ic_fuze"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/fuzeIcon"
android:layout_marginLeft="10sp"
android:layout_marginTop="15sp"
android:layout_gravity="center"
android:fontFamily="#font/avenir"
android:text="Fuze"
android:textColor="#ffffff"
android:textSize="25dp" />
<ImageView
android:layout_width="40sp"
android:layout_height="40sp"
android:layout_alignParentEnd="true"
android:layout_marginTop="10sp"
android:layout_marginEnd="10dp"
android:src="#drawable/ic_arrow_right" />
</RelativeLayout>
<RelativeLayout
android:id="#+id/tachankaButton"
android:layout_below="#+id/fuzeButton"
android:layout_width="match_parent"
android:layout_height="60sp"
android:orientation="horizontal">
<ImageView
android:id="#+id/tachankaIcon"
android:layout_width="50sp"
android:layout_height="50sp"
android:layout_marginTop="5sp"
android:layout_marginLeft="10sp"
android:src="#drawable/ic_tachanka"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/tachankaIcon"
android:layout_marginLeft="10sp"
android:layout_marginTop="15sp"
android:layout_gravity="center"
android:fontFamily="#font/avenir"
android:text="Tachanka"
android:textColor="#ffffff"
android:textSize="25dp" />
<ImageView
android:layout_width="40sp"
android:layout_height="40sp"
android:layout_alignParentEnd="true"
android:layout_marginTop="10sp"
android:layout_marginEnd="10dp"
android:src="#drawable/ic_arrow_right" />
</RelativeLayout>
</RelativeLayout>
</ScrollView>
</FrameLayout>

Try to remove the ViewTreeObserver.OnScrollChangedListener when the fragment is destroyed this will avoid any listener that can be attached to a destroyed fragment context not to be triggered whenever you leave and come back to this fragment.
First: make a global field for the listener
public class operatorTab extends Fragment {
...
ViewTreeObserver.OnScrollChangedListener mScrollListener = new ViewTreeObserver.OnScrollChangedListener() {
#Override
public void onScrollChanged() {
resetAllButtons();
}
};
Then set the listener wit the created field
private void scrollResetListener(){
scrollView.getViewTreeObserver().addOnScrollChangedListener(mScrollListener);
}
Then remove the listener.. I believe it's typically should be in onDestroyView() >> but also try it in onStop() or onPause if it didn't work
This also will solve memory leak of this listener whenever its callback is triggered after the Fragment's view is destroyed
#Override
public void onDestroyView() {
super.onDestroyView();
scrollView.getViewTreeObserver().removeOnScrollChangedListener(mScrollListener);
}
UPDATE
onStop()/onPause() worked for me
The reason that it didn't work with onDestroyView() because the OperatorTab fragment is a part of one of the ViewPager pages; and by default ViewPager loads a number of close pages in the background to be ready for the next page scroll; loading this pages include some of the fragment lifecycle callbacks like onCreateView, onStart, but not onResume.
When you leave the OperatorTab by scrolling the ViewPager to the next tab/page; onDestroyView() won't be created if the ViewPager decides that OperatorTab is a part of the cached/close pages that the user might return back to it later; and therefore the listener still there and after a few swipes of the pager, the OperatorTab fragment can be detached from the context leaving the listener there with memory leaks...
So, the best way in ViewPager fragment (or any View that loads its fragments in advance) is to stop any listeners once you leave the page, i.e. in onPause or onStop callbacks and not waiting until they are destroyed.

A possible reason for this error is that you are calling getResources() NOT in an Activity without using a context. So, you need to use context.getResources() instead where context may be one of these here . In you instance, I think getContext() will work.
So, I think you should search for all the times you are calling getResources and see if you are using a context or not.
The explanation for this error in a simple way is that you are trying to access the context required in getResources() before the fragment is instantiated.

My buttons and Views do nothing after inflating the layout they are in so avoid null object error

My Main Activity. This is where all my code is.
package com.abhiandroid.tablayoutexample;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.VideoView;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import com.google.android.gms.ads.InterstitialAd;
import com.google.android.gms.ads.MobileAds;
public class MainActivity extends AppCompatActivity {
FrameLayout simpleFrameLayout;
TabLayout tabLayout;
ImageButton imageRopo;
Button btn_show;
InterstitialAd interstitialAd;
AdView adView1,adView2;
TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LayoutInflater layoutInflater= (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View firstfrag =getLayoutInflater().inflate(R.layout.fragment_first,null);
View thirdfrag =getLayoutInflater().inflate(R.layout.fragment_third,null);
btn_show = (Button)thirdfrag.findViewById(R.id.bt_show);
adView1= (AdView)thirdfrag.findViewById(R.id.ad_view);
adView2= (AdView)thirdfrag.findViewById(R.id.ad_view2);
imageRopo = (ImageButton)firstfrag.findViewById(R.id.buttonropo);
textView = (TextView)firstfrag.findViewById(R.id.testview);
imageRopo.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(android.content.Intent.ACTION_VIEW);
intent.setData(Uri.parse("https://www.youtube.com"));
startActivity(intent);
textView.setText("The button works");
}
});
MobileAds.initialize(this, "ca-app-pub-8708219564656739~8048449285");
AdRequest adRequest = new AdRequest.Builder().addTestDevice(AdRequest.DEVICE_ID_EMULATOR)
.addTestDevice("355696115338836").build();
adView1.loadAd(adRequest);
adView2.loadAd(adRequest);
interstitialAd = new InterstitialAd(this);
interstitialAd.setAdUnitId("ca-app-pub-8708219564656739/2401085524");
interstitialAd.loadAd(new AdRequest.Builder().addTestDevice(AdRequest.DEVICE_ID_EMULATOR)
.addTestDevice("355697115338836").build());
btn_show.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
interstitialAd.show();
}
});
// get the reference of FrameLayout and TabLayout
simpleFrameLayout = (FrameLayout) findViewById(R.id.simpleFrameLayout);
tabLayout = (TabLayout) findViewById(R.id.simpleTabLayout);
// Create a new Tab named "First"
TabLayout.Tab firstTab = tabLayout.newTab();
firstTab.setText("Apps"); // set the Text for the first Tab
firstTab.setIcon(R.drawable.app); // set an icon for the
// first tab
tabLayout.addTab(firstTab); // add the tab at in the TabLayout
// Create a new Tab named "Second"
TabLayout.Tab secondTab = tabLayout.newTab();
secondTab.setText("Products"); // set the Text for the second Tab
secondTab.setIcon(R.drawable.company); // set an icon for the second tab
tabLayout.addTab(secondTab); // add the tab in the TabLayout
// Create a new Tab named "Third"
TabLayout.Tab thirdTab = tabLayout.newTab();
thirdTab.setText("Donate"); // set the Text for the first Tab
thirdTab.setIcon(R.drawable.donation); // set an icon for the first tab
tabLayout.addTab(thirdTab); // add the tab at in the TabLayout
// perform setOnTabSelectedListener event on TabLayout
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
// get the current selected tab's position and replace the fragment accordingly
Fragment fragment = null;
switch (tab.getPosition()) {
case 0:
fragment = new FirstFragment();
break;
case 1:
fragment = new SecondFragment();
break;
case 2:
fragment = new ThirdFragment();
break;
}
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.simpleFrameLayout, fragment);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
ft.commit();
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
}
My activit_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:clickable="true"
android:focusable="true"
android:gravity="center"
android:orientation="vertical"
tools:context=".MainActivity">
<android.support.design.widget.TabLayout
android:id="#+id/simpleTabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabBackground="#android:color/darker_gray"
app:tabIndicatorColor="#f00"
app:tabSelectedTextColor="#f00"
app:tabTextColor="#000" />
<FrameLayout
android:id="#+id/simpleFrameLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#9C27B0">
</FrameLayout>
</LinearLayout>
The buttons and views are in different fragments hence me having to inflate the layouts they are in.
This is my firstfragment.xml. This is where one of my button and one of my TextView is.
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ffeadb"
tools:context=".FirstFragment">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#f7c5a8"
android:orientation="vertical"
tools:context=".FirstFragment"
tools:layout_editor_absoluteY="1dp">
<TextView
android:id="#+id/textView23"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
android:fontFamily="#font/roboto_bold"
android:gravity="center"
android:text="Why Choose China when you have the option for Indian?"
android:textSize="37sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="#+id/imageView"
android:layout_width="106dp"
android:layout_height="109dp"
android:layout_marginStart="24dp"
android:layout_marginLeft="24dp"
android:layout_marginTop="208dp"
android:layout_marginEnd="281dp"
android:layout_marginRight="281dp"
android:src="#drawable/tiktokl"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/textView22"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="12dp"
android:layout_marginLeft="12dp"
android:layout_marginTop="148dp"
android:layout_marginEnd="35dp"
android:layout_marginRight="35dp"
android:gravity="center"
android:text="Why Choose Chinese when you can choose an Indian Alternative."
android:textSize="16sp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.255"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="#+id/imageView3"
android:layout_width="114dp"
android:layout_height="114dp"
android:layout_marginStart="149dp"
android:layout_marginLeft="149dp"
android:layout_marginTop="192dp"
android:layout_marginEnd="148dp"
android:layout_marginRight="148dp"
android:src="#drawable/red_arrow"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageButton
android:id="#+id/buttonropo"
android:layout_width="132dp"
android:layout_height="118dp"
android:layout_marginStart="281dp"
android:layout_marginLeft="281dp"
android:layout_marginTop="183dp"
android:layout_marginEnd="24dp"
android:layout_marginRight="24dp"
android:layout_marginBottom="5dp"
android:adjustViewBounds="true"
android:background="#android:color/transparent"
android:baselineAlignBottom="false"
android:cropToPadding="true"
android:src="#drawable/roposoapplog"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/testview"
android:layout_width="88dp"
android:layout_height="19dp"
android:layout_marginStart="168dp"
android:layout_marginLeft="168dp"
android:layout_marginTop="336dp"
android:layout_marginEnd="155dp"
android:layout_marginRight="155dp"
android:textSize="25sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
</ScrollView>
My ThirdFragement Activity file is very empty.
package com.abhiandroid.tablayoutexample;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
public class FirstFragment extends Fragment {
public FirstFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_first, container, false);
}
}
Before inflating the layouts, I would get a null object error and after inflating them they no-longer seem to work. They don't do anything. As you can see in my MainActivity.java file I had made is so that when a user clicks a button it redirects them to a website. I even made a TextView that updates itself when the Button is clicked so that I know that the Button is working. I have spent days trying to fix this error and have made no progress. I suspect it is related to some code being wrong while making the fragments.

You should add the logic for your Fragment's views inside your Fragment class.
So, instead of doing the logic for the button in the Activity, do it under the Fragment onCreateView():
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_first, container, false);
imageRopo = (ImageButton) v.findViewById(R.id.buttonropo);
textView = (TextView) v.findViewById(R.id.testview);
imageRopo.setOnClickListener(new View.OnClickListener() { ...
// ... and so on
return v;
}

Fragment Does Not Appear In Android

I recently learned about Fragments in Android and was building a notepad application to practice them.
Idea: The idea behind the app is simple. I press the button to add a new note. A CardView Viewgroup turns visible. The fragment will be housed within this CardView.
Problem: When I press the button to add a new note, the fragment does not pop up.
MainActivity.java
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import androidx.cardview.widget.CardView;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import java.util.Objects;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private CardView fragmentCardView;
private Button newNoteButton;
private FragmentManager fragmentManager = getSupportFragmentManager();
private FragmentTransaction fragmentTransaction;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setActionBar();
newNoteButton = findViewById(R.id.new_note_button);
fragmentCardView = findViewById(R.id.fragment_cardView);
}
void setActionBar(){
Objects.requireNonNull(getSupportActionBar()).setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
getSupportActionBar().setDisplayShowCustomEnabled(true);
getSupportActionBar().setCustomView(R.layout.layout_custom_action_bar);
}
void showCreateNoteFragment(){
CreateNoteFragment createNoteFragment = CreateNoteFragment.newInstance();
fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.fragment_cardView, createNoteFragment);
fragmentTransaction.commit();
fragmentCardView.setVisibility(View.VISIBLE);
}
#Override
public void onClick(View v) {
if (v == newNoteButton)
showCreateNoteFragment();
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#F2F2F2"
tools:context=".MainActivity">
<ListView
android:id="#+id/notes_listView"
android:layout_width="match_parent"
android:layout_height="667dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"/>
<Button
android:id="#+id/new_note_button"
android:layout_width="350dp"
android:layout_height="50dp"
android:layout_marginTop="27dp"
android:fontFamily="#font/nunito_bold"
android:text="#string/new_note_button_string"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/notes_listView"/>
<androidx.cardview.widget.CardView
android:id="#+id/fragment_cardView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="100dp"
android:layout_marginBottom="100dp"
android:layout_marginStart="25dp"
android:layout_marginEnd="25dp"
android:visibility="invisible"/>
</androidx.constraintlayout.widget.ConstraintLayout>
CreateNoteFragment.java
package com.example.notepadapplication;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
public class CreateNoteFragment extends Fragment implements View.OnClickListener {
private EditText inputEditText;
public CreateNoteFragment() {
// Required empty public constructor
}
static CreateNoteFragment newInstance(){
return new CreateNoteFragment();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_create_note, container, false);
inputEditText = rootView.findViewById(R.id.input_editText);
Button saveButton = rootView.findViewById(R.id.save_button);
saveButton.setOnClickListener(this);
return rootView;
}
#Override
public void onClick(View v) {
String saveButtonText = inputEditText.getText().toString();
}
}
fragment_create_note.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
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"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_marginTop="100dp"
android:layout_marginBottom="100dp"
android:layout_marginStart="25dp"
android:layout_marginEnd="25dp"
android:background="#F2F2F2"
tools:context=".CreateNoteFragment">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/header_textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="#string/display_fragment_header_string"
android:layout_marginTop="10dp"
android:textAlignment="center"
android:textSize="20sp"
android:fontFamily="#font/nunito_bold"/>
<View
android:id="#+id/divider_view"
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_marginTop="5dp"
android:layout_marginStart="15dp"
android:layout_marginEnd="15dp"
android:layout_below="#id/header_textView"
android:background="#000000" />
<EditText
android:id="#+id/input_editText"
android:layout_width="match_parent"
android:layout_height="475dp"
android:layout_below="#id/divider_view"
android:layout_alignParentStart="true"
android:layout_alignParentEnd="true"
android:layout_marginTop="20dp"
android:layout_marginStart="5dp"
android:layout_marginEnd="5dp"
android:padding="10dp"
android:inputType="textMultiLine"
android:gravity="top"
android:background="#FFFFFF"
tools:ignore="Autofill,LabelFor,TextFields" />
<Button
android:id="#+id/save_button"
android:layout_width="250dp"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="10dp"
android:text="#string/save_button_string"
android:fontFamily="#font/nunito_bold"/>
</RelativeLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
Could anyone check why the fragment isn't popping up? Thanks for the help, guys.
P.S.: I think that the application might become a little bloated because of all the ViewGroups that I'm using. If you guys have a better way to design this, by all means, I would love any input.

When I press the button to add a new note, the fragment does not pop up.
This is expected since your button doesn't know what to do when pressed.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setActionBar();
newNoteButton = findViewById(R.id.new_note_button);
// Button will call activity's onClick whenever it's clicked
newNoteButton.setOnClickListener(this);
fragmentCardView = findViewById(R.id.fragment_cardView);
}

Android Tablayout,why tabs not moving?

I was following this tutorial https://www.youtube.com/watch?v=zcnT-3F-9JA I've used his code from github, but output is wrong. I've put 3 tabs on the top, and when I press on tab, activity supposed to change, but in reality, nothing happens, I still have only my main_activity on the screen. Hope someone will help. Here is my codes
PS - Yes I have also 3 xml files for every fragment (even I have also main_activity, but I have to find out what's wrong, and then will asign 1tab with main activity). I have also 3 java files for this 3 tabs.
XML
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FFFFFF"
android:orientation="vertical"
tools:context=".MainActivity">
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<android.support.v4.view.ViewPager
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
<TextView
android:id="#+id/lvltext"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/expa"
android:layout_centerInParent="true"
android:fontFamily="#font/futuracondensed"
android:text="#string/leveltext"
android:textColor="#color/black"
android:textSize="30sp" />
<TextView
android:id="#+id/lvlnum"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/lvltext"
android:layout_centerInParent="true"
android:fontFamily="#font/futuracondensed"
android:text="#string/levelnum"
android:textColor="#color/black"
android:textSize="30sp" />
<ImageView
android:id="#+id/girl"
android:layout_width="wrap_content"
android:layout_height="262dp"
android:layout_below="#id/lvlnum"
android:src="#drawable/girl" />
<Button
android:id="#+id/button"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#id/girl"
android:fontFamily="#font/futuracondensed"
android:text="#string/button"
android:textColor="#color/black" />
<ImageView
android:id="#+id/girl2"
android:layout_width="match_parent"
android:layout_height="258dp"
android:layout_below="#id/button"
android:src="#drawable/fitnessmodel" />
<Button
android:id="#+id/button2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#id/girl2"
android:fontFamily="#font/futuracondensed"
android:text="#string/button2"
android:textColor="#color/black" />
<LinearLayout
android:layout_below="#id/tabs"
android:id="#+id/expa"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical">
<TextView
android:id="#+id/team_a_score"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fontFamily="#font/futuracondensed"
android:gravity="center"
android:paddingBottom="5dp"
android:text="0"
android:textColor="#color/black"
android:textSize="60sp" />
</LinearLayout>
<View
android:layout_width="1dp"
android:layout_height="match_parent"
android:layout_marginTop="0dp"
android:background="#color/black" />
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical">
<TextView
android:id="#+id/team_b_score"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="#font/futuracondensed"
android:gravity="center"
android:paddingBottom="5dp"
android:text="100"
android:textColor="#color/black"
android:textSize="60sp" />
</LinearLayout>
</LinearLayout>
</RelativeLayout>
</android.support.v4.widget.NestedScrollView>
Java
public class MainActivity extends AppCompatActivity {
private SectionsPageAdapter mSectionsPageAdapter;
private ViewPager mViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mSectionsPageAdapter = new SectionsPageAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = findViewById(R.id.container);
setupViewPager(mViewPager);
TabLayout tabLayout = findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
}
private void setupViewPager(ViewPager viewPager) {
SectionsPageAdapter adapter = new SectionsPageAdapter(getSupportFragmentManager());
adapter.addFragment(new Tab1Fragment(), "TAB1");
adapter.addFragment(new Tab2Fragment(), "TAB2");
adapter.addFragment(new Tab3Fragment(), "TAB3");
viewPager.setAdapter(adapter);
}
#Override
public void onResume() {
super.onResume();
}
}
public class SectionsPageAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
public SectionsPageAdapter(FragmentManager fm) {
super(fm);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
}

use this XML as given in the library u have followed then whatever design u want to add them to the fragment layouts u have taken.things will work fine
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.chirag.slidingtabsusingviewpager.MainActivity">
<android.support.v7.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/toolbar"
android:background="#color/colorPrimary"
android:minHeight="?attr/actionBarSize"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="SlidingTabsUsingViewPager"
android:textSize="20dp"/>
</android.support.v7.widget.Toolbar>
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/tablayout"
android:background="#color/colorPrimary"
android:minHeight="?attr/actionBarSize"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
</android.support.design.widget.TabLayout>
<android.support.v4.view.ViewPager
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:id="#+id/pager">
</android.support.v4.view.ViewPager>
</LinearLayout>

On your getItem() method. Use Switch and return fragments their instead of adding all the fragments in addFragment method.
public Fragment getItem(int position){
switch(position){
case 0 : return new Tab1Fragment();
case 1 : return new Tab2Fragment();
case 2 : return new Tab3Fragment();
}
}

try this code:
OneFragment.java
OneFragment.java
package info.androidhive.materialtabs.fragments;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import info.androidhive.materialtabs.R;
public class OneFragment extends Fragment{
public OneFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_one, container, false);
}
}
fragment_one.xml
fragment_one.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"
tools:context="info.androidhive.materialtabs.fragments.OneFragment">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/one"
android:textSize="40dp"
android:textStyle="bold"
android:layout_centerInParent="true"/>
</RelativeLayout>
activity_main.xml
<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:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light" />
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="fixed"
app:tabGravity="fill"/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
MainActivity.java
package info.androidhive.materialtabs.activity;
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import java.util.ArrayList;
import java.util.List;
import info.androidhive.materialtabs.R;
import info.androidhive.materialtabs.fragments.OneFragment;
import info.androidhive.materialtabs.fragments.ThreeFragment;
import info.androidhive.materialtabs.fragments.TwoFragment;
[![enter image description here][1]][1]public class MainActivity extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new
ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new OneFragment(), "ONE");
adapter.addFragment(new TwoFragment(), "TWO");
adapter.addFragment(new ThreeFragment(), "THREE");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
and add the main activity calling 3 tabs
private class MyPagerAdapter extends FragmentPagerAdapter {
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int pos) {
switch(pos) {
case 0: return SimpleFragment.newInstance("FirstFragment, Instance 1");
case 1: return PieView.newInstance("SecondFragment, Instance 1");
case 2: return PieView1.newInstance("ThirdFragment, Instance 1");
case 3: return DataSaveDetails.newInstance("ThirdFragment, Instance 1");
default:
}
return null;
}
it works please try this

Button click force closes the activity

My problem is when I click bSA button I encounter error and the activity closes.
java.lang.runtimeexception unable to start activity componentinfo ...
here is my code
Data.java :
package com.example.myapp;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Data extends Activity implements View.OnClickListener {
Button start, startFor;
EditText sendET;
TextView gotAnswer;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.get);
initialize();
}
private void initialize() {
start = (Button) findViewById(R.id.bSA);
startFor = (Button) findViewById(R.id.bSAFR);
sendET = (EditText) findViewById(R.id.etSend);
gotAnswer = (TextView) findViewById(R.id.tvGot);
start.setOnClickListener(this);
startFor.setOnClickListener(this);
}
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.bSA:
String bread = sendET.getText().toString();
Bundle basket = new Bundle();
basket.putString("key", bread);
Intent a = new Intent(getApplicationContext(), OpenedClass.class);
a.putExtras(a);
startActivity(a);
break;
case R.id.bSAFR:
break;
}
}
}
get.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/etSend" android:layout_gravity="center_horizontal"/>
<Button
android:layout_below="#+id/etSend"
android:layout_alignParentRight="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Start Activity"
android:id="#+id/bSA"/>
<Button
android:layout_toLeftOf="#+id/bSA"
android:layout_alignTop="#+id/bSA"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Start Activity for Results"
android:id="#+id/bSAFR"/>
<TextView
android:layout_below="#+id/bSAFR"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
android:id="#+id/tvGot"/>
</RelativeLayout>
=============================================================
OpenedClass.java
package com.example.myapp;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioGroup;
import android.widget.TextView;
public class OpenedClass extends Activity implements View.OnClickListener, RadioGroup.OnCheckedChangeListener {
TextView question, test;
Button returnData;
RadioGroup selectionList;
String gotBread;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.send);
initialize();
Bundle gotBasket = getIntent().getExtras();
gotBread = gotBasket.getString("key");
question.setText(gotBread);
}
private void initialize() {
question = (TextView) findViewById(R.id.tvQuestion);
test = (TextView) findViewById(R.id.tvText);
returnData = (Button) findViewById(R.id.bReturn);
returnData.setOnClickListener(this);
selectionList = (RadioGroup) findViewById(R.id.rgAnswers);
selectionList.setOnCheckedChangeListener(this);
}
#Override
public void onClick(View view) {
}
#Override
public void onCheckedChanged(RadioGroup arg0, int arg1) {
// TODO Auto-generated method stub
switch (arg1) {
case R.id.rCrazy:
break;
case R.id.rFun:
break;
case R.id.rBoth:
break;
}
}
}
send.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Hosein is ..."
android:id="#+id/tvQuestion"/>
<RadioGroup
android:id="#+id/rgAnswers"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Crazy"
android:id="#+id/rCrazy"
/>
<RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Super Fun"
android:id="#+id/rFun"/>
<RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Both"
android:id="#+id/rBoth"/>
</RadioGroup>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Return"
android:id="#+id/bReturn"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Text"
android:id="#+id/tvText"/>
</LinearLayout>

Intent a = new Intent(getApplicationContext(), OpenedClass.class);
a.putExtras(a);
You cannot put a inside itself. This causes infinite recursion and stack overflow.
You probably wanted
a.putExtras(basket);