dataBinding

DataBinding

DataBinding

DataBinding是谷歌发布的一种数据绑定的框架，能够省去findviewbyid()的使用，大量减少Activity的代码。

启用DataBinding

dataBinding {
    enabled = true
}

xml转换

在xml布局中的根布局中，使用Alt + Enter，点击Convert to data binding layout，就可以转换为DataBinding需要的布局。

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">

    <data>
        <variable
            name="user"
            type="com.wumeng.jetpackproject.databinding.User" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".databinding.DataBindingActivity">

        <TextView
            android:id="@+id/tv_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="16dp"
            android:layout_marginTop="8dp"
            android:text="@{user.name}"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/tv_password"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="16dp"
            android:text="@{user.password}"
            app:layout_constraintStart_toStartOf="@+id/tv_name"
            app:layout_constraintTop_toBottomOf="@+id/tv_name" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

1. 使用layout作为根布局。
2. data标签用于声明使用的数据。

####### 定义数据

class User {

    private String name;

    private String password;

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

在Activity中使用

public class DataBindingActivity extends AppCompatActivity {

    private ActivityDataBindingBinding dataBindingBinding;

    private User user;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        dataBindingBinding = DataBindingUtil.setContentView(this, R.layout.activity_data_binding);

        user = new User("WM","123456");
        dataBindingBinding.setUser(user);
    }

}