[JAVA] (Android) Try to display static text using DataBinding

Introduction

Record it as a study of Data Binding. This time, it's just the beginning of displaying the text.

Introducing Data Binding

Add the following to app gradle

build.gradle

android {
    dataBinding {
        enabled = true
    }
}

Prepare a class (User) to bind

User.java

public class User {
  private String name;
  private String email;

  public User(String name, String email) {
    this.name = name;
    this.email = email;
  }

  public String getName() { return name; }
  public String getEmail() { return email; }
}

layout settings

point

• Enclose the root of the xml file with the layout tag. ⇒ A Binding class is automatically created according to the xml file name. Example: activity_main.xml => ActivityMainBinding
• Describe the object to be used in the data tag
• variable name is any name
• type = "com.example.project name (lowercase).class name to bind" (User this time)
• Enclose in @ {} to access the properties of the bind object from View
• Example: Access getName () of User.java with @ {user.name}
• The contents of @ {} are designed to allow null, and even if it is null, NullPointerException will not occur.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Binding Objects -->
    <data>
      <!--Named user(Any)Is tied to the User class object-->
      <variable name="user" type="com.example.databinding.User" />
    </data>

    <!-- View -->
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{user.name}" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{user.email}" />
    </LinearLayout>
</layout>

Bind the object

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private User user = new User("Taro", "[email protected]");

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //Get an instance of Binding
        ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
        //Associate xml user with MainActivity user
        binding.setUser(user);
    }

in conclusion

Next, I would like to implement a dynamic display. next: Dynamically change text using DataBinding (https://qiita.com/kilalabu/items/3cded5e7c560de2ed05c)

Reference site

https://qiita.com/Omoti/items/a83910a990e64f4dbdf1#step0-%E5%B0%8E%E5%85%A5 Thank you very much