如何使用 xml 中的视图引用将参数传递给使用数据绑定的函数？

Question

I am using data binding to call a function of my viewmodel but the function requires the values of the edittext. But I don't know how to pass the value of other views.

Here is the xml code. In this I want to pass the value of password edittext to viewmodel on click of the button. Suggest me a way to do this other than using onclickListeners in fragment and calling the function from there.

 <com.google.android.material.textfield.TextInputLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="@dimen/small_margin"
            android:hint="@string/password_hint">

            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/password_input"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="textPassword" />

        </com.google.android.material.textfield.TextInputLayout>

        <androidx.appcompat.widget.AppCompatButton
            android:id="@+id/login_button"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@drawable/big_action_button_red"
            android:text="@string/login_button_text"
            android:onClick="@{()->viewModel.validateUser(password_input.text)}"/>

Answer 1

Use Two-way data binding with the password TextView , that way you can have the current value of the field in a LiveData in your ViewModel . Then simply get that value inside your ViewModel when validate() is called.

<com.google.android.material.textfield.TextInputEditText
                android:id="@+id/password_input"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="@={viewmodel.passowrd}"
                android:inputType="textPassword" />

Answer 2

Just create string variable in your viewmodel for password field like this

  var password:String?=null

Now add this in password_input field just like this

 android:text="@={viewmodel.password}" // this directly assign value of password field to password variable

Now at last remove parameter in validateUser method and directly use password variable in this method.