Создание фрагментов и использование вкладок для Android

android:layout_width="match_parent"
android:layout_height="match_parent"

android:layout_width="wrap_content"
android:layout_height="wrap_content"

//return PlaceholderFragment.newInstance(position + 1);

switch (position){
case 0:
BlankFragment1 bf1= new BlankFragment1();
return bf1;
case 1:
BlankFragment2 bf2= new BlankFragment2();
return bf2;
case 2:
BlankFragment3 bf3= new BlankFragment3();
return bf3;
default:
return null;
}

<!--?xml version="1.0" encoding="utf-8"?-->
<android.support.design.widget.coordinatorlayout 
xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:app="http://schemas.android.com/apk/res-auto" 
xmlns:tools="http://schemas.android.com/tools" 
android:id="@+id/main_content" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:fitssystemwindows="true" 
tools:context="ru.maxfad.myfragments.MainActivity">

    <android.support.design.widget.appbarlayout 
android:id="@+id/appbar" android:layout_width="match_parent" 
android:layout_height="wrap_content" 
android:paddingtop="@dimen/appbar_padding_top" 
android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.toolbar 
android:id="@+id/toolbar" 
android:layout_width="match_parent" 
android:layout_height="?attr/actionBarSize" 
android:layout_weight="1" 
android:background="?attr/colorPrimary" 
app:layout_scrollflags="scroll|enterAlways" 
app:popuptheme="@style/AppTheme.PopupOverlay" 
app:title="@string/app_name">

        </android.support.v7.widget.toolbar>

        <android.support.design.widget.tablayout 
android:id="@+id/tabs" 
android:layout_width="match_parent" 
android:layout_height="wrap_content">

            <android.support.design.widget.tabitem 
android:id="@+id/tabItem" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:text="@string/tab_text_1">

            <android.support.design.widget.tabitem 
android:id="@+id/tabItem2" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:text="@string/tab_text_2">

            <android.support.design.widget.tabitem 
android:id="@+id/tabItem3" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:text="@string/tab_text_3">

        </android.support.design.widget.tabitem>
</android.support.design.widget.tabitem>
</android.support.design.widget.tabitem>
</android.support.design.widget.tablayout>
    </android.support.design.widget.appbarlayout>

    <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">

    <android.support.design.widget.floatingactionbutton 
android:id="@+id/fab" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:layout_gravity="end|bottom" 
android:layout_margin="@dimen/fab_margin" 
app:srccompat="@android:drawable/ic_dialog_email">

</android.support.design.widget.floatingactionbutton>
</android.support.v4.view.viewpager>
</android.support.design.widget.coordinatorlayout>

<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="ru.maxfad.myfragments.BlankFragment3">

    <relativelayout 
android:layout_width="match_parent" 
android:layout_height="match_parent">

        <textview 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:layout_alignparenttop="true" 
android:layout_centerhorizontal="true" 
android:layout_margintop="220dp" 
android:text="@string/hello_blank_fragment" 
android:id="@+id/textView"></textview>

        <button android:id="@+id/button" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:layout_below="@+id/textView" 
android:layout_centerhorizontal="true" 
android:layout_margintop="55dp" 
android:text="Button"></button>
    </relativelayout>

</framelayout>

<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="ru.maxfad.myfragments.BlankFragment2">

    <relativelayout 
android:layout_width="match_parent" 
android:layout_height="match_parent">

        <textview 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:layout_alignparenttop="true" 
android:layout_centerhorizontal="true" 
android:layout_margintop="181dp" 
android:text="@string/hello_blank_fragment"></textview>
    </relativelayout>

</framelayout>

<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="ru.maxfad.myfragments.BlankFragment1">

    <relativelayout 
android:layout_width="match_parent" 
android:layout_height="match_parent">

        <textview 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:layout_alignparentstart="true" 
android:layout_alignparenttop="true" 
android:layout_marginstart="114dp" 
android:layout_margintop="113dp" 
android:text="@string/hello_blank_fragment"></textview>
    </relativelayout>
</framelayout>

package ru.maxfad.myfragments;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
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 android.view.Menu;
import android.view.MenuItem;
import android.view.View;

public class MainActivity extends AppCompatActivity {

    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link FragmentPagerAdapter} derivative, which will keep every
     * loaded fragment in memory. If this becomes too memory intensive, it
     * may be best to switch to a
     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    private SectionsPagerAdapter mSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    private ViewPager mViewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);

        mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */


    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {

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

        @Override
        public Fragment getItem(int position) {
            // getItem is called to instantiate the fragment for the given page.
            // Return a PlaceholderFragment (defined as a static inner class below).
            //return PlaceholderFragment.newInstance(position + 1);

        switch (position){

            case 0:
                BlankFragment1 bf1 = new BlankFragment1();
                return  bf1;
            case 1:
                BlankFragment2 bf2 = new BlankFragment2();
                return bf2;
            case 2:
                BlankFragment3 bf3 = new BlankFragment3();
                return bf3;
                default:
                    return null;
        }




        }

        @Override
        public int getCount() {
            // Show 3 total pages.
            return 3;
        }
    }
}

package ru.maxfad.myfragments;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


public class BlankFragment1 extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_blank_fragment1, container, false);
    }


}

package ru.maxfad.myfragments;

import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;



public class BlankFragment2 extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_blank_fragment2, container, false);
    }


}

package ru.maxfad.myfragments;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;



public class BlankFragment3 extends Fragment {


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_blank_fragment3, container, false);
    }


}