fragment按键事件想不通

Question

第一行代码第三版，学习到Fragment的动态添加，由于button.setOn的插件方法已经废弃了，然后像往常一样

使用findViewById(R.id.button),
启动就闪退，不要button相关代码就能正常启动，试着在LeftFragent类里添加了viewbinding插件，
binding.button.setOnClickListener{}，binding显示红色没能正常引用.

MainActivity.kt

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        binding.button.setOnClickListener {
            replaceFragment(AnotherRightFragment())
        }
        replaceFragment(RightFragment())
    }

    private fun replaceFragment(fragment: Fragment) {

        val fragmentManager = supportFragmentManager
        val transaction = fragmentManager.beginTransaction()
        transaction.replace(R.id.rightLayout, fragment)
        transaction.commit()
    }
}

LeftFragment.kt

class LeftFragment : Fragment() {

    private var _binding: LeftFragmentBinding? = null
    private val binding get() = _binding!!

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {
        _binding = LeftFragmentBinding.inflate(inflater, container, false)
        return binding.root
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}

RightFragment.kt

class RightFragment: Fragment() {
    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.right_fragment, container, false)
    }
}

AnotherRightFragment.kt

class AnotherRightFragment: Fragment() {
    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.another_right_fragment, container, false)
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/leftFrag"
        android:name="android.example.fragmenttest.LeftFragment"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="match_parent" />

    <FrameLayout
        android:id="@+id/rightLayout"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="match_parent" >
    </FrameLayout>

</androidx.appcompat.widget.LinearLayoutCompat>

left_fragent.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:backgroundTint="#868686"
        android:text="@string/button"/>

</androidx.appcompat.widget.LinearLayoutCompat>

right_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#00ff00">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="@string/right_fragment"
        android:textSize="24sp"/>

</androidx.appcompat.widget.LinearLayoutCompat>

another_right_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#ffff00">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/another_right_fragment"
        android:textSize="24sp"
        android:layout_gravity="center_horizontal"/>

</androidx.appcompat.widget.LinearLayoutCompat>

请教各位，如果分别用findViewById和viewbinding两种方法，该如何实现呢。

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Answer 1

你这里用法不太对
1.button是leftFragment中的控件，你还没有吧LeftFragment添加到activity中的
2.button需要在LeftFragment中关联，而不是activity中