前提：
有一个 ViewModel 类，有一个 xml，xml 绑定了 ViewModel .

1. @{click}

    //xml:
    <Button
         android:layout_width="match_parent"
         android:layout_height="48dp"
         android:onClick="@{click}"
    />

    //ViewModel:
    public void click(View view){
        //do
    }

​

2. 不带参数：@{() -> viewModel.click()}

    //xml:
    <Button
         android:layout_width="match_parent"
         android:layout_height="48dp"
         android:onClick="@{() -> viewModel.click()}"
    />

    //ViewModel:
    public void click(){
         //do   
    }

3. @{viewModel::click}

    /xml:
    <Button
         android:layout_width="match_parent"
         android:layout_height="48dp"
         android:onClick="@{viewModel::click}"
    />
     
    /ViewModel:
    public void click(View view){
        //do
    }

tip: 如果是在其它类中设置点击方法，如 EventHandlers.java, 其实与上面一致

    //xml:
    <variable
        name="handler"
        type="com.xx.xxx.EventHandlers" />
    
    <Button
         android:layout_width="match_parent"
         android:layout_height="48dp"
         android:onClick="@{handler::click}" />        

//类：绑定handler,如同绑定ViewModel那样

    EventHandlers handler = new EventHandlers();
    binding.setHandler(handler);

    //EventHandlers
    public void click(View view){
        //do
    }

4. 带参数：@{() -> viewModel.click(obj.id)}

    /xml:
    <variable
        name="viewModel"
        type="com.xx.xxx.ViewModel" />
    
    <variable
        name="obj"
        type="com.xx.xxx.User" />

    <Button
         android:layout_width="match_parent"
         android:layout_height="48dp"
         android:onClick="@{() -> viewModel.click(obj.id)}"
    />

    /ViewModel:
    public void click(long id){
         //do   
    }

5. 自定义View中

    /xml:
    <variable
       name="iconView"
       type="com.adsale.ChinaPlas.ui.view.IconView" />
       
    <RelativeLayout
        android:id="@+id/rl_icon_view"
        android:layout_width="match_parent"
        android:layout_height="55dp"
        android:onClick="@{iconView.clickListener}"
    >    
        

    /IconView:
    public final ObservableField<OnClickListener> clickListener=new ObservableField<>();


    /xml所在的Activity类：
    binding.iconView.clickListener.set(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
              Toast.makeText(getApplicationContext(),"iconView",Toast.LENGTH_SHORT).show();
     }
    });

6. 带参数

     android:onClick="@{()->loadingModel.chooseLang(2)}"
     public void chooseLang(int language) {
            LogUtil.i(TAG, "language=" + language);
     }