A : How to use DataBinding?
B : such as read this circle.
Open setting
First , open your file which is in app/build.gradle , and you can see the android' field , you need to write the code like this to open the dataBinding' Setting.
android {
...
dataBinding {
enabled = true
}
}
Create a bean
Second , create a bean which is named User in your package , and create two variable as well as generate their constroctor. Two variable , name and age , were String variable and int variable . you must use the public to decorate two variable ,otherwise it wiil catch the Exception such as like this :
Could not find accessor package.User.name
here are the full code
public class User {
public String name;
public String age;
public User(String name, String age) {
this.name = name;
this.age = age;
}
}
Modify the xml
Thrid , add the <layout> label to root in your xml . by the way ,you need to write the android nameSpace in the layout element. create the <data> label which in the <layout> label . create the <import> label to import the User class which created juts now . create the <variable> label next to the <import> with two property which is called name and type. you can write the name which just like user, and type must be call User .
Now , you can give the text to TextView by Using anroid:text="@{user.name}"
here are the full code:
<?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"ja>
<data>
<import type="com.ppjun.android.databinding.User"/>
<variable
name="user"
type="User"/>
</data>
<RelativeLayout
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_below="@+id/toolbar"
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@{user.name}"
/>
<TextView
android:id="@+id/age"
android:layout_below="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@{user.age}"/>
</RelativeLayout>
</layout>
Connect to the data
Final , gradle sync to generate the AcrivityMainBingding .
In the MainActivity 'onCreate method , create the AcrivityMainBingding binding by Using the method DataBindingUtil.setCotnentView(this,R.layout.activity_main);
new the User variable by it's constroctor.
user binding.setUser(user); to binding the xml.
here are the full code:
ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
User user = new User("ppjun", "23");
binding.setUser(user);
run the application you will see the TextView text like ppjun and 23.
Summary
- DataBinding is easy for us to set the text without findviewbyid.
- The next article will show you more things about DataBinding.
Thanks for your watching.
:)
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