fragment控件

Question

问题遇到的现象和发生背景

自主学习Android Studio-App开发基础时按课件使用Fragment控件时出现问题

问题相关代码，请勿粘贴截图

activity_main.xml文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    tools:context=".MainActivity">
    <fragment
        android:name="com.example.fragment.Fragment_Menu"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        ></fragment>
    <fragment
        android:name="com.example.fragment.Fragment_info"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="2"
        ></fragment>
</LinearLayout>

MainActivity.java文件：

package com.example.fragment;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

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

Fragment_Menu.java文件：

package com.example.fragment;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;

//Fragment_Menu类将碎片和对应的布局产生关联
public class Fragment_Menu extends Fragment {
    @Nullable
    @Override
    //用于构建某个碎片和布局的关系
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v =inflater.inflate(R.layout.leftlayout,container,false);
        return v;
    }
}

Fragment_info.java文件：

package com.example.fragment;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

public class Fragment_info extends Fragment_Menu{
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v =inflater.inflate(R.layout.rightlayout,container,false);
        return v;
    }
}

运行结果及报错内容

运行结果：

报错内容：
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.fragment, PID: 20119
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.fragment/com.example.fragment.MainActivity}: android.view.InflateException: Binary XML file line #14 in com.example.fragment:layout/activity_main: Binary XML file line #14 in com.example.fragment:layout/activity_main: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3449)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
Caused by: android.view.InflateException: Binary XML file line #14 in com.example.fragment:layout/activity_main: Binary XML file line #14 in com.example.fragment:layout/activity_main: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #14 in com.example.fragment:layout/activity_main: Error inflating class fragment
Caused by: java.lang.IllegalArgumentException: Binary XML file line #14: Must specify unique android:id, android:tag, or have a parent with an id for com.example.fragment.Fragment_Menu
at androidx.fragment.app.FragmentManagerImpl.onCreateView(FragmentManagerImpl.java:3177)
at androidx.fragment.app.FragmentController.onCreateView(FragmentController.java:134)
at androidx.fragment.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:357)
at androidx.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:336)
at android.view.LayoutInflater.tryCreateView(LayoutInflater.java:1067)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:995)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:959)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:1121)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
at android.view.LayoutInflater.inflate(LayoutInflater.java:680)
at android.view.LayoutInflater.inflate(LayoutInflater.java:532)
at android.view.LayoutInflater.inflate(LayoutInflater.java:479)
at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696)
at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:170)
at com.example.fragment.MainActivity.onCreate(MainActivity.java:12)
at android.app.Activity.performCreate(Activity.java:8000)
at android.app.Activity.performCreate(Activity.java:7984)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3422)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

我的解答思路和尝试过的方法

无

我想要达到的结果

正常运行

Answer 1

哈哈哈，麻了，在fragment控件中加个id就行了，不知道什么原理