原因：android.view.InflateException：二进制XML文件行＃13：错误夸大了类片段

Question

I am trying to add fragments to the activity through code to swap between them but I keep getting 'Caused by: android.view.InflateException: Binary XML file line #13: Error inflating class fragment'

Here is the code for the main activity:

package com.example.user.timetable_test;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;


public class Set_Up extends FragmentActivity{

    //MiscData data = MiscData.getInstance();


    @Override
    protected void onCreate(Bundle savedInstanceState){

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_set__up);

        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction ft = fm.beginTransaction();

        Fragment wel = new frag_welcome();

        wel.setArguments(getIntent().getExtras());

        // Add the fragment to the 'fragment_container' FrameLayout
        ft.add(R.id.fragment_container, wel);


    }


}

XML file:

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_set_up"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.user.timetable_test.Set_Up">
    <fragment
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
    />
</RelativeLayout>

For the fragment

package com.example.user.timetable_test;

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


public class frag_welcome extends Fragment{

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

        View view = inflater.inflate(R.layout.frag_set_up_welcome, container, false);

        return view;
    }
}

XML file:

<?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">

    <TextView
        android:text="@string/welcome_to_the_timetable_app"
        android:layout_width="150dp"
        android:layout_height="wrap_content" android:id="@+id/textView2"
        android:layout_marginTop="100dp"
        android:textAppearance="@style/TextAppearance.AppCompat.Headline"
        android:textAlignment="center"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"/>
    <Button
        android:text="@string/start_set_up_butt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="69dp"
        android:id="@+id/startSetUp" style="@style/Widget.AppCompat.Button.Borderless"
        android:layout_below="@+id/textView3" android:layout_centerHorizontal="true"/>
    <TextView
        android:text="@string/press_start_set_up_to_start"
        android:layout_height="wrap_content"
        android:id="@+id/textView3"
        android:textAppearance="@style/TextAppearance.AppCompat.Headline"
        android:textAlignment="center"
        android:layout_marginTop="24dp"
        android:layout_width="170dp" android:layout_below="@+id/textView2"
        android:layout_centerHorizontal="true"/>
</RelativeLayout>

Answer 1

Reading your code...

// Add the fragment to the 'fragment_container' FrameLayout

You probably need to change

 <fragment
    android:id="@+id/fragment_container"

To

 <FrameLayout 
    android:id="@+id/fragment_container"

Or, not use the Java code to create the Fragment and simply add the class attribute to the XML fragment block. From the documentation...

The android:name attribute in the <fragment> specifies the Fragment class to instantiate in the layout.

Otherwise, you can show the Fragment like so

Fragment wel = new WelcomeFragment();  // correct naming schema 
wel.setArguments(getIntent().getExtras());
getSupportFragmentManager()
    .beginTransaction()
    .add(R.id.fragment_container, wel)
    .commit();

Answer 2

Declare your fragment_container like this,

   <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_set_up"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.user.timetable_test.Set_Up">

    <!-- Can be any child of ViewGroup: RelativeLayout/LinearLayout/... -->
    <FrameLayout
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
    />
</RelativeLayout>