如何使用Fragment进行数据绑定

我试图遵循官方谷歌文档https://developer.android.com/tools/data-binding/guide.html的数据绑定示例

除了我试图将数据投标应用到一个片段，而不是一个活动。

编译时我目前得到的错误是

错误:(37,27)没有指定资源类型(at 'text' with value '@{marsdata.martianSols})。

onCreate for fragment是这样的:

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    MartianDataBinding binding = MartianDataBinding.inflate(getActivity().getLayoutInflater());
    binding.setMarsdata(this);
}

onCreateView for fragment看起来像这样:

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    return inflater.inflate(R.layout.martian_data, container, false);
}

和部分我的布局文件片段看起来像这样:

<?xml version="1.0" encoding="utf-8"?>

<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <variable
            name="marsdata"
            type="uk.co.darkruby.app.myapp.MarsDataProvider" />
    </data>
...

        <TextView
            android:layout_height="wrap_content"
            android:layout_width="wrap_content"
            android:text="@{marsdata.martianSols}"
        />

    </RelativeLayout>
</layout>

我的怀疑是MartianDataBinding不知道它应该与哪个布局文件绑定-因此出现错误。有什么建议吗?

当前回答

Kotlin中的最短路径;

class HomeFragment : Fragment(R.layout.fragment_home) {


override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)
    val binding = FragmentHomeBinding.bind(view)
    // todo 
    }

2022-03-15 23:07:10

其他回答

Kotlin 语法：

lateinit var binding: MartianDataBinding
override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    binding = DataBindingUtil.inflate(inflater, R.layout.martian_data, container, false)
    return binding.root
}

2017-09-26 12:56:25

Kotlin中的另一个例子:

override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    val binding = DataBindingUtil
            .inflate< MartianDataBinding >(
                    inflater,
                    R.layout.bla,
                    container,
                    false
            )

    binding.modelName = // ..

    return binding.root
}

注意，“MartianDataBinding”的名称取决于布局文件的名称。如果文件命名为“marti_data”，那么正确的名称应该是MartianDataBinding。

2017-12-31 14:17:00

这是你在kotlin中可以做到的:

//Pass the layout as parameter to the fragment constructor    
class SecondFragment : Fragment(R.layout.fragment_second) {

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

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        _binding = FragmentSecondBinding.bind(view)  //if the view is already inflated then we can just bind it to view binding.

    }

    //Note: Fragments outlive their views. Make sure you clean up any references to the binding class
    // instance in the fragment's onDestroyView() method.
    override fun onDestroyView() {
        Toast.makeText(activity, "On destroy", Toast.LENGTH_SHORT).show()
        super.onDestroyView()
        _binding = null
    }
}

你可以像这样从你的布局中访问视图元素:

binding.tvName.text = "Messi"

其中tvName是视图元素的id。

2021-09-08 18:11:39

一个完整的数据绑定片段的例子

FragmentMyProgramsBinding是为res/layout/fragment_my_programs生成的绑定类

public class MyPrograms extends Fragment {
    FragmentMyProgramsBinding fragmentMyProgramsBinding;

    public MyPrograms() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
    FragmentMyProgramsBinding    fragmentMyProgramsBinding = DataBindingUtil.inflate(inflater, R
                .layout.fragment_my_programs, container, false);
        return fragmentMyProgramsBinding.getRoot();
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

    }
}

2018-09-19 12:39:53

科特林

         override fun onCreateView(
                 inflater: LayoutInflater, container: ViewGroup?,
                 savedInstanceState: Bundle?
            ): View? 
    { 
                 val binding = FragmentFirstBinding.inflate(inflater,container,false)      
               return  binding.root;
            

}

其中FragmentFirstBinding是由android studio使用视图绑定自动生成的。在我的代码片段名称是FirstFragment。

首先，您需要将这一行添加到构建中。Gradle(app模块)文件。

buildFeatures{
        viewBinding true
    }

2022-01-28 13:13:42

如何使用Fragment进行数据绑定

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