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
<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
<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
<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
<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>
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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