How to Save Fragment State in Fragment

Question

MainActivity

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import com.astuetz.PagerSlidingTabStrip;

public class MainActivity extends AppCompatActivity {

    Fragment f = new Fragment();
    LoginFragment f1=new LoginFragment();
    SignupFragment f2=new SignupFragment();
    public static PagerSlidingTabStrip tabs;
    public static ViewPager pager;
    private MyPagerAdapter adapter;
    @Override
 protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tabs = (PagerSlidingTabStrip) findViewById(R.id.tabs);
        pager = (ViewPager) findViewById(R.id.viewpager);
        adapter = new MyPagerAdapter(getSupportFragmentManager());
        pager.setAdapter(adapter);
        tabs.setViewPager(pager);
    }

    public class MyPagerAdapter extends FragmentPagerAdapter {

        private final String[] TITLES = {"Login","SignUp"};

        public MyPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
 public CharSequence getPageTitle(int position) {
            return TITLES[position];
        }

        @Override
 public int getCount() {
            return TITLES.length;
        }

        @SuppressWarnings("unused")
        private Fragment frag(Fragment f) {
            FragmentManager manager = getSupportFragmentManager();
            FragmentTransaction transaction = manager.beginTransaction();
            transaction.add(R.id.viewpager, f);
            transaction.commit();
            return f;
        }
        @Override
 public Fragment getItem(int position) {
            if(position==0)
                f = f1;//Home
 else if(position==1)
                f = f2;//DesiIndian
 return f;
        }

    }
}

LoginActivity

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;


/**
 * A simple {@link Fragment} subclass.
 */
public class LoginFragment extends Fragment
{
    Button co;
    TextView tv_count;
    int count=0;
    private Bundle savedState = null;
    @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
        // Inflate the layout for this fragment
 View view= inflater.inflate(R.layout.fragment_login, container, false);
        tv_count=(TextView)view.findViewById(R.id.tv_count);
        co=(Button)view.findViewById(R.id.button);

        co.setOnClickListener(new View.OnClickListener() {
            @Override
 public void onClick(View v) {
                count++;
                tv_count.setText(""+count);
            }
        });
        return view;
    }

    @Override
 public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        if(savedInstanceState!=null) {
            count = savedInstanceState.getInt("someVarA");
            tv_count.setText("" + count);
        }
    }

    @Override
 public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("someVarA", count);
    }
}

SignupFragment

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;


/**
 * A simple {@link Fragment} subclass.
 */
public class LoginFragment extends Fragment
{
    Button co;
    TextView tv_count;
    int count=0;
    private Bundle savedState = null;
    @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
        // Inflate the layout for this fragment
 View view= inflater.inflate(R.layout.fragment_login, container, false);
        tv_count=(TextView)view.findViewById(R.id.tv_count);
        co=(Button)view.findViewById(R.id.button);

        co.setOnClickListener(new View.OnClickListener() {
            @Override
 public void onClick(View v) {
                count++;
                tv_count.setText(""+count);
            }
        });
        return view;
    }

    @Override
 public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        if(savedInstanceState!=null) {
            count = savedInstanceState.getInt("someVarA");
            tv_count.setText("" + count);
        }
    }

    @Override
 public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("someVarA", count);
    }
}

activity_main

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:orientation="vertical"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 android:id="@+id/activity_main"
 android:layout_width="match_parent"
 android:layout_height="match_parent">

    <com.astuetz.PagerSlidingTabStrip
 android:id="@+id/tabs"
 app:pstsShouldExpand="true"
 app:pstsTextAllCaps="true"
 android:layout_width="match_parent"
 android:layout_height="48dp" />

    <android.support.v4.view.ViewPager
 android:id="@+id/viewpager"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:background="@android:color/white" />

</LinearLayout>

fragment_login

<LinearLayout 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:orientation="vertical"
 tools:context="com.social.chaudhary.fragmentstatesaved.LoginFragment">

    <Button
 android:id="@+id/button"
 android:text="Count"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content" />

    <!-- TODO: Update blank fragment layout -->
 <TextView
 android:id="@+id/tv_count"
 android:layout_marginTop="10dp"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:text="Count" />

</LinearLayout>

signup_fragment

<LinearLayout 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:orientation="vertical"
 tools:context="com.social.chaudhary.fragmentstatesaved.SignupFragment">

    <EditText
 android:id="@+id/et"
 android:hint="User"
 android:focusable="true"
 android:inputType="text"
 android:focusableInTouchMode="true"
 android:layout_width="match_parent"
 android:layout_height="wrap_content" />

</LinearLayout>

gradel

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
 buildToolsVersion "25.0.2"
 defaultConfig {
        applicationId "com.social.chaudhary.fragmentstatesaved"
 minSdkVersion 17
 targetSdkVersion 25
 versionCode 1
 versionName "1.0"
 testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
 }
    buildTypes {
        release {
            minifyEnabled false
 proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
 }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
 })
    compile 'com.android.support:appcompat-v7:25.3.1'
 testCompile 'junit:junit:4.12'
 compile 'com.astuetz:pagerslidingtabstrip:1.0.1'
}

Attachment: FragmentStateSaved.rar

Nikunj Satasiya · Answer

To correctly save the instance state of Fragment you must do the following: 1. within the fragment save instance state by paramount onSaveInstanceState() and restore in onActivityCreated() : @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); ... if (savedInstanceState != null ) { //Restore the fragment's state here } } ... @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); //Save the fragment's state here } 2. And necessary purpose within the activity you have got to save lots of the fragment's instance in onSaveInstanceState() and restore in onCreate() . public void onCreate(Bundle savedInstanceState) { ... if (savedInstanceState != null ) { //Restore the fragment's instance mContent = getSupportFragmentManager().getFragment(savedInstanceState myFragmentName ); ... } ... } @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); //Save the fragment's instance getSupportFragmentManager().putFragment(outState myFragmentName  mContent); }