Android 带viewbinding的BaseFragment

要在android应用程序中使用

viewbinding

，我基本上是为

活动创建基类

&

片段

，以删除每次编写膨胀代码时的样板文件

活动：

BaseActivity

带有

viewbinding

：

abstract class BaseActivity<VB : ViewBinding> : AppCompatActivity() {
    
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = getViewBinding()
    }

    abstract fun getViewBinding(): VB

}

片段：

BaseFragment

：

abstract class BaseFragment<VB : ViewBinding> : Fragment() {

    var binding: VB? = null

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        binding = getViewBinding(view)
    }

    abstract fun getViewBinding(view: View): VB
}

class DemoFragment : BaseFragment<DemoFragmentBinding>() {

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        //problem is here
        binding.txtData.text="Something"
    }

    override fun getViewBinding(view: View): DemoFragmentBinding = DemoFragmentBinding.bind(view)

}

//Add this for the onCreateView implementation
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
        binding = DemoFragmentBinding.inflate(LayoutInflater.from(context), null, false)
        val view = binding!!.root
        return view
    }

demo_fragment.xml：

<FrameLayout 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=".ui.fragments.DemoFragment">

    <TextView
        android:id="@+id/txt_data"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="Hello" />

</FrameLayout>

---

我浏览了文档，不确定这是否会破坏

BaseFragment

中的抽象模式，但我用这个更改测试了您的代码，它成功了。只有

DemoFragment

中发生了更改：

abstract class BaseFragment<VB : ViewBinding> : Fragment() {

    var binding: VB? = null

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        binding = getViewBinding(view)
    }

    abstract fun getViewBinding(view: View): VB
}

class DemoFragment : BaseFragment<DemoFragmentBinding>() {

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        //problem is here
        binding.txtData.text="Something"
    }

    override fun getViewBinding(view: View): DemoFragmentBinding = DemoFragmentBinding.bind(view)

}

//Add this for the onCreateView implementation
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
        binding = DemoFragmentBinding.inflate(LayoutInflater.from(context), null, false)
        val view = binding!!.root
        return view
    }

然后我在

onViewCreated

中进行了测试：

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        //problem is here
        binding?.txtData?.text="Something"

    }

它成功了。我查看的文档是

---

我认为这样做仍然可以避免一些样板文件，但是由于视图绑定膨胀不同（例如，

DemoFragmentBinding.inflate等），每个片段都需要使用
onCreateView
覆盖
您需要重写BaseFragment中的
onCreateView
，并初始化viewbinding

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

那就换这一行

override fun getViewBinding(view: View): DemoFragmentBinding = DemoFragmentBinding.bind(view)

与

基本片段：

abstract class BaseFragment<VB : ViewBinding> : Fragment() {
    private var _binding: VB? = null
    val binding get() = _binding!!

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

    abstract fun getViewBinding(): VB
}

class DemoFragment : BaseFragment<DemoFragmentBinding>() {

    override fun getViewBinding() = DemoFragmentBinding.inflate(layoutInflater)

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        binding.apply {
            txtData.text = "Something"
        }
    }
}

抽象类BaseFragment:Fragment（）{
私有变量绑定：VB？=null
val binding get（）=\u binding！！
覆盖创建视图(
充气机，
容器：视图组？，
savedInstanceState:捆绑？
)：查看{
_binding=getViewBinding（）
返回binding.root
}
抽象趣味getViewBinding（）：VB
}

DemoFragment：

abstract class BaseFragment<VB : ViewBinding> : Fragment() {
    private var _binding: VB? = null
    val binding get() = _binding!!

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

    abstract fun getViewBinding(): VB
}

class DemoFragment : BaseFragment<DemoFragmentBinding>() {

    override fun getViewBinding() = DemoFragmentBinding.inflate(layoutInflater)

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        binding.apply {
            txtData.text = "Something"
        }
    }
}

class DemoFragment:BaseFragment（）{
override fun getViewBinding（）=DemoFragmentBinding.充气（LayoutFlater）
覆盖已创建的视图（视图：视图，保存状态：捆绑？）{
super.onViewCreated（视图，savedInstanceState）
应用{
txtData.text=“某物”
}
}
}
你能显示片段的xml文件吗？@Amin更新了这个问题。这能回答你的问题吗？不，它不适用于包含的布局！我可以直接使用
androidx.fragment:fragment ktx:1.2.0
在片段构造函数参数中传递
demo_fragment.xml
，而不重写onCreateView，但我不想这样做！虽然谢谢你的回答。你说可以传递layout_文件是什么意思？传递layout xml并不会给你viewbinding。您需要使用
DemoFragmentBinding.inflate（
method）专门充气。我已经更新了问题。