效果图如下:

项目结构图如下:

Fragment1:

package com.demo.dongtaifragment;

import android.app.Fragment;

import android.os.Bundle;

import android.support.annotation.NonNull;

import android.support.annotation.Nullable;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

public class Fragment2 extends Fragment {

    //显示faragemnt1 自己要显示的内容

    @Nullable

    @Override

    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragemnt2, null);

        return view;

    }

}

Fragment2:

package com.demo.dongtaifragment;

import android.app.Fragment;

import android.os.Bundle;

import android.support.annotation.NonNull;

import android.support.annotation.Nullable;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

public class Fragment2 extends Fragment {

    //显示faragemnt1 自己要显示的内容

    @Nullable

    @Override

    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragemnt2, null);

        return view;

    }

}

MainActivity:

package com.demo.dongtaifragment;

import android.app.FragmentManager;

import android.app.FragmentTransaction;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.WindowManager;

public class MainActivity extends AppCompatActivity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        //[1]获取手机的分辨率

        WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);

        int width = wm.getDefaultDisplay().getWidth();

        int height = wm.getDefaultDisplay().getHeight();

        FragmentManager fragmentManager  = getFragmentManager();

        //开启事务

        FragmentTransaction beginTransaction = fragmentManager.beginTransaction();

        Fragment1 fragment1 = new Fragment1();

        //判断横竖

        if(height>width){

            //说明是竖屏  加载一个fragment

           beginTransaction.replace(android.R.id.content, new Fragment1());

        }else{

            //说明是横屏

            beginTransaction.replace(android.R.id.content, new Fragment2());

        }

        //最后一步 记得commit

        beginTransaction.commit();

    }

}

fragemnt1.xml:

<?xml version="1.0" encoding="utf-8"?>

<android.support.constraint.ConstraintLayout

    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"

    android:layout_height="match_parent">

    <TextView

        android:layout_width="wrap_content"

        android:layout_height="match_parent"

        android:text="我是fragment1竖屏的内容"

        android:textSize="20sp"

        />

</android.support.constraint.ConstraintLayout>

fragemnt2.xml:

<?xml version="1.0" encoding="utf-8"?>

<android.support.constraint.ConstraintLayout

    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"

    android:layout_height="match_parent">

    <TextView

        android:layout_width="wrap_content"

        android:layout_height="match_parent"

        android:text="我是fragment2横屏的内容"

        android:textSize="30sp"

        />

</android.support.constraint.ConstraintLayout>