Android FragmentTabHost界面切换

主布局:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    tools:context=".MainActivity">

    <!--标题-->
    <android.support.v4.app.FragmentTabHost
        android:layout_width="match_parent"
        android:id="@+id/fragmentTabHost"
        android:layout_height="wrap_content">

    </android.support.v4.app.FragmentTabHost>

    <!--占位-->
    <FrameLayout
        android:id="@+id/frameLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

    </FrameLayout>

</android.support.constraint.ConstraintLayout>

主类:

package com.example.fragmenttabhost;

import android.support.v4.app.FragmentTabHost;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

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

        fragmentTabHost=findViewById(R.id.fragmentTabHost);

        //第一个参数:上下文环境  第二个参数:getSupportFragmentManager() 第三个参数:布局占位id
        fragmentTabHost.setup(this,getSupportFragmentManager(),R.id.frameLayout);

        //第一个参数:id.标题内容 第二个参数:单个界面类  第三个参数:bundle发送信息(一般为null)
        fragmentTabHost.addTab(fragmentTabHost.newTabSpec("tab1").setIndicator("标题1"),Fragment01.class,null);
        fragmentTabHost.addTab(fragmentTabHost.newTabSpec("tab2").setIndicator("标题2"),Fragment02.class,null);
        fragmentTabHost.addTab(fragmentTabHost.newTabSpec("tab3").setIndicator("标题3"),Fragment03.class,null);
    }
}

如何创建Fragement类:

然后Fragment01的xml可以自定义布局界面,很方便