[移动开发]Android viewbinding视图绑定 使用

方便自己后面的深入学习记录一下使用，viewbinding 使用必须在Androidstudio3.6版本上支持。官网：https://developer.android.google.cn/topic/libraries/view-binding#kotlin

1.启用视图绑定，在项目添加：

android {
        ...
        viewBinding {
            enabled = true
        }
    }
    

注意：如果您希望在生成绑定类时忽略某个布局文件，请将?tools:viewBindingIgnore="true"?属性添加到相应布局文件的根视图中，为某个模块启用视图绑定功能后，系统会为该模块中包含的每个 XML 布局文件生成一个绑定类。每个绑定类均包含对根视图以及具有 ID 的所有视图的引用。系统会通过以下方式生成绑定类的名称：将 XML 文件的名称转换为驼峰式大小写，并在末尾添加“Binding”一词。每个绑定类还包含一个?getRoot()?方法，用于为相应布局文件的根视图提供直接引用

2.在各个引用布局添加绑定（当xml布局 使用了<include />控件，比较添加id,来调用）：

Activity（onCreate()方法使用）:

    private lateinit var binding: ResultProfileBinding

    override fun onCreate(savedInstanceState: Bundle) {
        super.onCreate(savedInstanceState)
        binding = ResultProfileBinding.inflate(layoutInflater)
        val view = binding.root
        setContentView(view)
    }
    

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fragment ( onCreateView() 方法使用 )

    private var _binding: ResultProfileBinding? = null
    // This property is only valid between onCreateView and
    // onDestroyView.
    private val binding get() = _binding!!

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

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

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另一种写法（onViewCreated()）

/**
 * View Binding example with a fragment that uses the alternate constructor for inflation and
 * [onViewCreated] for binding.
 */
class BindFragment : Fragment(R.layout.fragment_blank) {

    // Scoped to the lifecycle of the fragment's view (between onCreateView and onDestroyView)
    private var fragmentBlankBinding: FragmentBlankBinding? = null

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        val binding = FragmentBlankBinding.bind(view)
        fragmentBlankBinding = binding
         //使用
        binding.textViewFragment.text = getString(string.hello_from_vb_bindfragment)
    }

    override fun onDestroyView() {
        // Consider not storing the binding instance in a field, if not needed.
        fragmentBlankBinding = null
        super.onDestroyView()
    }
}

dialog(参考):

mBinding = DialogDemoBinding.inflate(layoutInflater);
setContentView(mBinding.getRoot());

adapter?（参考）:

public class DemoAdapter extends RecyclerView.Adapter<DemoAdapter.ViewHolder> {
    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new ViewHolder(ItemDemoBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
    }
    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        holder.binding.textView2.setText("demo");

    }
    @Override
    public int getItemCount() {
        return 0;
    }
    public static class ViewHolder extends RecyclerView.ViewHolder {
        ItemDemoBinding binding;
        public ViewHolder(@NonNull ItemDemoBinding itemDemoBinding) {
            super(itemDemoBinding.getRoot());
            this.binding = itemDemoBinding;
        }
    }
}

这里感谢这位大佬的文章分享，引用参考

https://www.jianshu.com/p/66728b95baaa

还有activity和fragment的封装?参考：

public class BaseActivity<T extends ViewBinding> extends AppCompatActivity {
  protected T viewBinding;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      ParameterizedType type = (ParameterizedType) getClass().getGenericSuperclass();
      Class cls = (Class) type.getActualTypeArguments()[0];
      try {
          Method inflate = cls.getDeclaredMethod("inflate", LayoutInflater.class);
          viewBinding = (T) inflate.invoke(null, getLayoutInflater());
          setContentView(viewBinding.getRoot());
      } catch (NoSuchMethodException | IllegalAccessException| InvocationTargetException e) {
          e.printStackTrace();
      }
  }
}

//使用

public class MainActivity extends BaseActivity<ActivityMainBinding> {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        viewBinding.button.setText("这是 MainActivity ViewBinding");
        viewBinding.button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.d("MainView","点击按钮");
            }
        });
    }
}

public class BaseFragment<T extends ViewBinding> extends Fragment {
    protected T viewBinding;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        ParameterizedType type = (ParameterizedType) getClass().getGenericSuperclass();
        Class cls = (Class) type.getActualTypeArguments()[0];
        try {
            Method inflate = cls.getDeclaredMethod("inflate", LayoutInflater.class, ViewGroup.class, boolean.class);
            viewBinding = (T) inflate.invoke(null, inflater, container, false);
        }  catch (NoSuchMethodException | IllegalAccessException| InvocationTargetException e) {
            e.printStackTrace();
        }
        return viewBinding.getRoot();
    }
}

//使用
public class MainFragment extends BaseFragment<FragmentMainBinding>{
    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        viewBinding.button.setText("这是 MainFragment ViewBinding");
        viewBinding.button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.d("MainView","点击按钮");
            }
        });
    }
}

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