如何使用Fragment进行数据绑定

我正在尝试从官方谷歌文档https://developer.android.com/tools/data-binding/guide.html关注数据绑定示例

除了我试图将数据绑定应用于片段,而不是活动.

编译时我目前得到的错误是

Error:(37, 27) No resource type specified (at 'text' with value '@{marsdata.martianSols}.

onCreate 对于片段看起来像这样:

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

onCreateView 对于片段看起来像这样:

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

我的片段布局文件的部分内容如下所示:

    
        
    
...

        

    

我怀疑是MartianDataBinding不知道它应该绑定哪个布局文件 - 因此错误.有什么建议？

1> 小智..：

---

数据绑定实现必须在片段的onCreateView方法中,删除OnCreate方法中存在的任何数据Binding,onCreateView应如下所示:

public View onCreateView(LayoutInflater inflater, 
                         @Nullable ViewGroup container, 
                         @Nullable Bundle savedInstanceState) {
    MartianDataBinding binding = DataBindingUtil.inflate(
            inflater, R.layout.martian_data, container, false);
    View view = binding.getRoot();
    //here data must be an instance of the class MarsDataProvider
    binding.setMarsdata(data);
    return view;
}

---

几个小时我一直在努力解决这个问题.问题是我回错了.+1

2> Till..：

---

实际上,我们鼓励您使用inflate生成的Binding方法,而不是DataBindingUtil:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    MainFragmentBinding binding = MainFragmentBinding.inflate(inflater, container, false);
    //set variables in Binding
    return binding.getRoot();
}

DataBindingUtil.inflate()的文档:

仅当layoutId事先未知时才使用此版本.否则,使用生成的Binding的膨胀方法来确保类型安全的膨胀.

---

在这个例子中你在哪里设置片段布局id(例如R.layout.fragment_)？

3> Khemraj..：

---

即使其他答案也可能运作良好,但我想告诉最佳方法.

Binding class's inflate按照Android文档中的建议使用.

一种选择是通过膨胀,DataBindingUtil 但只有你不知道生成了绑定类.

- 你有自动生成binding class,使用该类而不是使用DataBindingUtil.

在Java中

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    HomeFragmentBinding binding = HomeFragmentBinding.inflate(inflater, container, false);
    //set binding variables here
    return binding.getRoot();
}

在科特林

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

在DataBindingUtil类文档中,您可以看到.

膨胀

T inflate (LayoutInflater inflater, 
                int layoutId, 
                ViewGroup parent, 
                boolean attachToParent)

仅当layoutId事先未知时才使用此版本.否则,使用生成的Binding的膨胀方法来确保类型安全的膨胀.

如果未生成布局biniding类,请参阅此答案.

4> Saman Sattar..：

---

如果您使用的是ViewModel和LiveData，这是足够的语法

Kotlin语法：

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    return MartianDataBinding.inflate(
        inflater,
        container,
        false
    ).apply {
        setLifecycleOwner(this@MartianData)
        vm = viewModel    // Attach your view model here
    }.root
}

5> 小智..：

---

在Android DataBinding中试试这个

FragmentMainBinding binding;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        binding = DataBindingUtil.inflate(inflater, R.layout.fragment_main, container, false);
        View rootView = binding.getRoot();
        initInstances(savedInstanceState);
        return rootView;
}

6> Imran Solank..：

---

可以简单地检索视图对象,如下所述

public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

View view = DataBindingUtil.inflate(inflater, R.layout.layout_file, container, false).getRoot();

return view;

}

7> 小智..：

---

在我的代码中工作.

private FragmentSampleBinding dataBiding;
private SampleListAdapter mAdapter;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    super.onCreateView(inflater, container, savedInstanceState);
    dataBiding = DataBindingUtil.inflate(inflater, R.layout.fragment_sample, null, false);
    return mView = dataBiding.getRoot();
}

8> muneikh..：

---

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
}