Android Data Binding pass arguments to onClick method

Is it possible to pass custom arguments to onClick method using the Data Binding Library? I have my layout xml file where I need to use the onClickListener:

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


<data>
<variable
name="viewModel"
type="com.productivity.tiktak.ui.tracker.viewModel.CategoryViewModel"/>
<variable
name="callback"
type="com.productivity.tiktak.ui.tracker.TrackerAdapter"/>
</data>


<android.support.v7.widget.CardView
android:onClick="@{callback.onCategoryClick(viewModel)}"
...
android:layout_width="match_parent"
android:layout_height="wrap_content">


<!-- ... Some stuff -->


</android.support.v7.widget.CardView>
</layout>

and I a have my click handler code here:

public void onCategoryClick(View view, CategoryViewModel categoryViewModel)
{
//handler code...
}

Is it possible to pass my CategoryViewModel object from xml to click handler?

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最佳答案

You can use a lambda expressions and pass the view in as a parameter.

 android:onClick="@{() -> callback.onCategoryClick(viewModel)}"

If you need the view, you can pass that as well with:

 android:onClick="@{(view) -> callback.onCategoryClick(view, viewModel)}"
小开

Multiple Ways:

Solution 1 (When you have Presenter)

You have a presenter or handler class like below

public class Presenter {
public void onSaveClick(View view, Task task){}
}

Now take variable of type Presenter in your layout. and set click like below.

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable name="task" type="com.android.example.Task" />
<variable name="presenter" type="com.android.example.Presenter" />
</data>
<LinearLayout ...>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="@{(view) -> presenter.onSaveClick(view, task)}"
/>
</LinearLayout>
</layout>

You can add any more arguments in this.

Please note that, you have to set these data variables in the onCreate() method. Like below

ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
binding.setTask(task);
binding.setPresenter(presenter);

Solution 2 (When you don't have Presenter)

Create a variable type of your Activity / Fragment

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable name="task" type="com.android.example.Task" />
<variable name="activity" type="com.example.MainActivity" />
</data>
<LinearLayout ...>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="@{(view) -> activity.onSaveClick(view, task)}"
/>
</LinearLayout>
</layout>

and make method in your activity which you want to call from binding layout. and don't forget to call setActivity(YourActivity.this) from Activity.

public class MainActivity extends AppCompatActivity {
public void onSaveClick(View view, Task task) {
System.out.println("MainActivity.onSaveClick");
}


@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
binding.setActivity(this);
binding.setTask(task);
}
}

Further reading Android DataBinding documentation

There are many other ways to set click, check this answer.


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